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Developing highly selective sensors for lipopolysaccharide (LPS) in plasma is vital for diagnosing sepsis since LPS is a significant cause of this condition. In this study, dansulfonyl derivatives were introduced as functional monomers in molecularly imprinted polymerization creatively, broadening the choice of functional monomers. The designed hydrophilic and hydrophobic functional monomers, tailored for polysaccharides and lipids of LPS, exhibited high selectivity, sensitivity, and biocompatibility with superior stability and reusability. The fluorescent sensor's limit of detection (LOD) was 0.46 µg/L with a linear response of 1–100 µg/L. The material's performance was compared to commercially available LPS detection kits. This study presents a viable method to fabricate molecularly imprinted fluorescent sensors that are highly responsive to LPS and can detect sepsis-inducing agents. Moreover, the designed sensors can potentially replace animal-derived reagents in LPS detection and can be applied to many solution systems. [Display omitted] • FLMIM based on hydrophilic-hydrophobic bifunctional monomers recognize LPS. • FLMIM can effectively replace the use of animal reagents in commercial kits. • Dansulfonyl derivatives were introduced as functional monomers creatively. • FLMIM measures LPS in human serum and milk. [ABSTRACT FROM AUTHOR]

The widely accepted method for detecting trace odor compounds such as 2-methylisoborneol (2-MIB) requires high-cost solid-phase microextraction coupled with gas chromatography-tandem mass spectrometry (SPME-GC/MS). As for now, cases that directly used SPME-GC/MS in the field are unseen, and most detection activities are still carried out in rigorous laboratory conditions. However, lengthy logistics and storage issues can compromise sample conditions, underscoring the significance of on-site detection methods. Here, we reported molecularly imprinted polymers-enabled headspace extracting and electrochemical sensing (MHEES) with the core feature of using the same piece of MIP for both headspace extracting and electrochemical sensing, allowing rapid on-site detection of trace 2-MIB in natural water bodies with a total cost of less than $2.10 per test. MHEES demonstrated exceptional sensitivity during extensively repeated laboratory experiments, achieving a detection limit of 3.7 ng∙L−1 and a standard deviation of 4.58 %. The practicality of MHEES was confirmed by conducting two rounds of on-site analyses on different reservoirs with fluctuating seasonal concentrations of 2-MIB. The developing flow of MHEES, from molecules docking to on-site application, was rigorous and could be cross-referenced to related research. The proposed MHEES design can potentially revolutionize the field of analytical chemistry by providing a versatile and affordable platform for on-site volatile compounds detection. It can readily adapt to various organic compounds and effectively address real-world challenges such as monitoring emerging pollutants, tracing disease biomarkers in body fluids, inspecting food safety, identifying chemical reaction intermediates, and supporting healthcare applications. [Display omitted] • MHEES can achieve the parts per trillion level on-site detection of 2-MIB. • MIP serves dual roles as 2-MIB headspace collector and sensing receptor. • MHEES can be developed cost-effectively, with less than $2.10 per test. • MHEES can be readily transferred to other analyte detections and applications. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymers (MIPs)-photoelectrochemical (PEC) strategy usually has only one photoactive material as the photocurrent signal. However, ratiometric technique commonly requires two selective signals, the detecting signal and reference signal. Therefore, ratiometric MIPs-PEC sensor has been rarely reported. This work presents a dual-wavelength ratiometric and differential MIPs-PEC platform with a digital multimeter readout, which designed for highly sensitive and selective detection of 2,4-dichlorophenoxyacetic acid (2,4-D). Gold nanoparticles modified porous silicon (Au NPs/PS) and the target (2,4-D) were employed as the light-active species, which can produce photocurrent at two different wavelengths (560 and 280 nm). Furthermore, the improved differential strategy was explored to enhance the anti-interference capability of sensors, by using the response difference between MIPs and non-imprinted polymers (NIPs) as the analytical signals. Benefiting from the sensitivity of ratiometric differential strategy and selectivity of differential MIPs method, this MIPs-PEC sensor affords a linear range of 1.0×10−11 to 8.0×10−8 M for detecting 2,4-D, with a detection limit of 8.9×10−13 M. As an important extension, this ratiometric differential MIPs-PEC technique could be used as an innovative and versatile approach for detecting other MIPs targets with similar properties, such as atrazine (AT) and triphenyl phosphate (TPhP). [Display omitted] • Ratiometric molecularly imprinted photoelectrochemical sensor was reported. • Gold nanoparticles/porous silicon was employed as the photoactive transducer. • The dual-wavelength photocurrent response for detecting 2,4-D was investigated. • The differential strategy remarkably improved the sensitivity of this sensor. • A portable photoelectrochemical sensor is built with a digital multimeter readout. [ABSTRACT FROM AUTHOR]

An ultrasensitive molecularly imprinted polymer-photoelectrochemical (MIP-PEC) sensing platform has been successfully fabricated for the detection of diflubenzuron (DBZ) under visible-light irradiation. The noval photoactive material was a ternary Bi 2 S 3 /BiVO 4 /TiO 2 nanotube arrays (BVT) heterojunction, grown in-situ on a Ti substrate. The distinct architecture of BVT featured BiVO 4 nanoparticles anchored onto TiO 2 nanotube arrays and wrapped by Bi 2 S 3 nanofibers. This innovative design, coupled with the aligned energy bands of BVT, significantly boosted visible-light absorption, and photo-induced charge separation and transfer, leading to an enhanced photocurrent response surpassing that of binary and single-component systems. The sensing platform displayed remarkable sensitivity and a broad detection range for DBZ with a linear range of 0.01–1000 ng mL−1 and a limit of detection of 1.25 pg mL−1. Its selectivity was further validated by comparable photocurrent responses in the presence of interfering substances, highlighting its accuracy in detecting DBZ in complex matrices. Additionally, the sensing platform demonstrated excellent stability and reproducibility, ensuring reliable results over multiple measurements. Evaluation of the sensing platform in real samples, including tap water and apples, has confirmed its high accuracy with recovery rates between 94.4 % and 103.4 %. Therefore, this visible-light-driven MIP-PEC sensing platform exhibits considerable potential for application in ultrasensitive detection of DBZ. This work offers novel insights into the in-situ preparation of high-performance sensors for applications in food safety and environmental monitoring. • An ultrasensitive MIP-PEC sensing platform has been developed for detection of diflubenzuron under visible light irradiation. • A novel Bi2S3/BiVO4/TiO2 nanotube arrays (BVT) heterojunction has been successfully constructed in situ on the electrode. • BVT exhibits an enhanced photocurrent response due to synergistic effects of structural coupling and energy band alignment. • The sensing platform shows remarkable selectivity, stability, reproducibility, and high accuracy in real samples. [ABSTRACT FROM AUTHOR]

The hybrid ratiometric fluorescence sensors (GKHMIPs & RKHMIPs) encompass luminescent substances incorporated within a core-shell architecture. These sensors manifest a diverse array of hues in response to variations in the concentration of alpha-fetoprotein, accomplished through disparities in the quantum dots (QDs)-protein response. This study is devoted to comprehending the principles governing the alteration of fluorescence during the recognition process of the ratiometric fluorescence sensor. A compensation mechanism, rooted in the correlation between fluorescence and protein response, is postulated through a fluorescence interaction model (multi-FRET model). Multi-FRET model can be divided into FRET process and Fluorescence compensate process (FCP), FCP occurs when electron orbits are filled, hindering the fluorescence resonance energy transfer process and leading to the return of excited state electrons to the ground state by alternative pathways. Based on the multi-FRET model we demonstrate the Sherpa formular to calculating the fluorescence-target relation. To assess the visual impact, the CIE-Lab model is introduced to validate the rationale behind the multi-color colorimetric model. The influence of different mixing ratios on the visualization effect is elucidated using the concentration fluorescence response model, and the optimal relationship between wavelength combinations in the tricolor mixing model is proposed. [Display omitted] • Use dual-fluorescence colorimetric particles for visual detection of AFP. • Propose a confinement fluorescence effect fluorescence increment model. • Propose multi-FRET process in the dual-fluorescence detection process. • Combined with CIE-LAB to verify the rationality of multi-FRET process. [ABSTRACT FROM AUTHOR]

Developing a simple, specific, and sensitive method for the detection of diuron is of utmost importance. Herein, a novel dual-quenching molecular imprinting polymers electrochemiluminescence (MIP-ECL) sensor, which effectively combined the "blocking effect" of MIPs and the competitive reaction between diuron and coreactant, was fabricated for high-performance analysis of diuron. Specifically, gold nanoclusters (AuNCs) were immobilized on the electrode interface to generate a robust ECL signal in the presence of triethylamine (TEA) as coreactant. The MIP was subsequently introduced employing thiophene as functional monomer and diuron as template molecule, with the cavities within the MIP utilized for diuron capture after elution. Upon the recombination of diuron, on the one hand, the electron transfer between the electrochemical oxidation product of AuNCs (AuNCs•+) and reactive radicals of TEA (TEA•) was hindered by diuron. On the other hand, a portion of TEA• was consumed by diuron to generate 3-(hydroxychlorophenyl)-1,1-dimethylurea (HCPDMU), a phenyl hydroxyl compound that could also potentially accept electron from TEA•, leading to a subsequent decline in TEA•. Both the mechanisms in turn weaken the generation of the excited-state AuNCs (AuNCs*) and reduce the ECL intensity, leading to the MIP-ECL sensor demonstrating excellent analytical performance for diuron detection. Innovatively, the interaction between diuron and TEA offered a novel research avenue for detecting diuron using the ECL system with TEA as coreactant. • It was found that diuron could quench the ECL signal of AuNCs/TEA system. • Based on the foundation, a MIP-ECL sensing platform was developed. • "Blocking effect" of MIPs and consumption of TEA by diuron were the quenched mechanisms. • The developed MIP-ECL sensor exhibited excellent performances for diuron detection. [ABSTRACT FROM AUTHOR]

Phenolic acids with extensive pharmacological activity often coexist with harmful impurities in traditional Chinese medicine (TCM). Therefore, it is imperative to meticulously scrutinize the presence of harmful components while assessing the efficacy of TCM. Here, we present a dual-template molecularly imprinted double emission ratio fluorescence sensor to selectively and sensitively detect methyl eugenol (ME) and aristolochic acid A (AAs). The sensor consists of CsPbBr 3 and CsPb(Br/I) 3 perovskite quantum dots molecularly imprinted polymer with dual emission peaks at 515 nm and 650 nm. Surprisingly, ME can only quench the emission peak at 650 nm, while AAs can quench both the two emission peaks. When ME and AAs coexist, their effect on the peak at 515 nm is similar to that of AAs, but the peak at 650 nm is quenched more. Therefore, it is possible to qualitatively identified whether the presence of ME, AAs or both of them based on the different colors of the sensors. In addition, the ratio of fluorescence intensity at 650 nm and 515 nm exhibits good linear relationships with both the concentrations of ME and AAs with the limit of detection of 8.3 nM for ME and 9.6 nM for AAs. Meanwhile, different concentrations of target molecules cause significant color changes, making it possible to visually semi-quantitatively detect AAs, ME and both of them. Moreover, the quenching mechanisms induced by ME and AAs are also investigated. Finally, the sensors have been successfully used to the determination of ME and AAs in Asarum of TCM. [Display omitted] • Preparation of dual-template molecularly imprinted double emission proportional fluorescence sensor. • Different colors of the sensor can be used to qualitatively identified ME, AAs or both of them. • Proportional fluorescence and visual determination of ME, AAs and both of them. • Dual-template molecularly imprinted improve the selective for the detection of ME and AAs in Chinese medicine Asarum. [ABSTRACT FROM AUTHOR]

This study integrates dopamine (DA) electropolymerization, epitope imprinting, and nanomaterials (i.e., gold nanoparticles (AuNP) and graphene quantum dots (GQD)) to develop three distinct electrochemical sensors (DA-AuNP-MIP, DA-GQD-MIP, and DA-AuNP-GQD-MIP) for detecting cardiac troponin I (cTnI) with assessing their sensitivity, selectivity, and specificity profiles. The sensors exhibited high affinity for the target biomarker, enabling detection within a concentration range of 0.01–20 ng mL−1, with dissociation constants ranging from 2.7 to 69 pM. The successful fabrication of sensors was also confirmed through atomic force microscopy (AFM), scanning electron microscopy (SEM), fluorescence microscopy, contact angle measurements, cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). The cTnI selectivity assessment of imprinted nanosensors compared to their non-imprinted counterparts at 0.01–2.5 ng mL−1 showed that the DA-AuNP-GQD-MIP sensor yielded a maximum imprinting factor of 5.9. A negligible cross-reactivity for DA-AuNP-MIP and DA-AuNP-GQD-MIP sensors was found against glucose, adenovirus epitope, another cTnI epitope, bovine serum albumin (BSA), transferrin, and neuron-specific enolase (NSE). Epitope specificity at various concentrations (10–60 nM), concentration-dependent cTnI detection in human serum (0.01–10 ng mL−1) and sensor recovery rates (0.1–10 ng mL−1) in human serum were determined with the best-performing sensor (i.e., DA-AuNP-GQD-MIP). The sensor demonstrated very high epitope specificity in comparison to another cTnI epitope as well as excellent detection performances in human serum studies. The newly engineered epitope-mediated electrochemical sensing platform showcases considerable potential for precise and straightforward diagnosis of coronary artery diseases, aiming to materialize a cost-effective Point-of-Care Testing (POCT) system. • Synthesis of novel cTnI-responsive nanocomposite materials with excellent epitope specificity. • Fabrication of first dopamine-based epitope-mediated electrochemical nanosensors for cTnI. • High specificity, sensitivity and affinity were achieved with fully synthetic receptors. • Successful application of the nanocomposite sensor was shown in serum samples analysis. • The established POCT platform can be used for detecting clinically important biomolecules. [ABSTRACT FROM AUTHOR]

Due to its common use as an insecticide during agricultural production, residual lambda-cyhalothrin (LC) in food and the environment presents a significant human health risk. Developing an accurate LC detection method that does not require pretreatment remains a challenge. This study developed a novel yellow carbon dots molecularly imprinted (YCDs@MIPs) polyvinylidene fluoride (PVDF) composite (YCDs@MIPs@PVDF) fluorescent membrane for rapid visual LC detection. This method required no pretreatments during analysis since the LC could be specifically adsorbed when the samples passed through the YCDs@MIPs@PVDF membrane, causing fluorescence quenching, while matrix-interfering components could be removed for the porous structure of the membrane. A smartphone was used for rapid visual LC detection based on membrane fluorescence color changes in a dark-box ultraviolet analyzer. In food with a 15 % PVDF content and 6 mL added YCDs@MIPs, LC was quantitatively detected in a broad concentration range (5–500 μg/L) with a limit of detection (LOD) of 0.039 μg/L to 0.16 μg/L, which was lower than the strictest EU2019/92 limit of 10 μg/L. The analysis time was reduced from over 8 h when using the GB 23200.121–2021 and GB/T20769–2008 national standard methods to 30 min, while the analytical procedure decreased from six steps to two. The visual detection strategy combining the YCDs@MIPs@PVDF composite fluorescent membrane with a smartphone provided a new rapid detection technique for composite membrane purification and fluorescence signal output function. • YCDs@MIPs@PVDF membrane combined with smartphone was developed for rapid detection of LC residue without pretreatment. • LC can be specifically adsorbed by YCDs@MIPs while interfering components be removed by the membrane. • Concentration of LC was shown visually and automatically in smartphone with color analysis app. • The method can be applied to detect LC content in foods and determine whether exceeds residual limit requirements. [ABSTRACT FROM AUTHOR]

An electrochemical and colorimetric dual-mode sensor is developed for the detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein (S protein). Pt nanoclusters (PtNCs) are successively decorated with 4-mercaptophenylboric acid (4-MPBA), S protein templates and poly(ionic liquids), and the surface molecularly imprinted PtNCs are obtained after the S protein templates are removed in acidic media. The rebinding of S protein can cause distinct changes in the electrochemical impedance spectroscopy (EIS) of the PtNCs, achieving sensitive electrochemical detection of S protein. In addition, the peroxidase-like activity of the PtNCs nanozyme is shielded after the rebinding of S protein, resulting in distinct changes in the color/visible spectra of 3,3',5,5'-tetramethylbenzidine (TMB) + hydrogen peroxide (H 2 O 2), and thus colorimetric detection of S protein is achieved. The linear range for S protein detecting is 1 pg mL−1 ∼ 1 μg mL−1, and the limits of detection for electrochemical and colorimetric method are 0.36 pg mL−1 and 0.57 pg mL−1, respectively. The developed dual-mode sensor shows high specificity and stability for S protein, and its reliability is also demonstrated by the detection of S protein in clinical serum sample. [Display omitted] • A dual-mode sensor is facilely designed for the detection of S protein. • The PtNCs nanozymes are introduced to surface molecular imprinting. • The rebinding of S protein can cause distinct changes in the EIS of MI-PtNCs. • The peroxidase-like activity of PtNCs is shielded after the rebinding of S protein. • The MI-PtNCs based dual-mode sensor has high specificity, stability, and reliability. [ABSTRACT FROM AUTHOR]

Here, we developed a self-powered bipolar electrode (SP-BPE) based dual-mode sensor with electrochromic (EC) and photoelectrochemical (PEC) techniques for the visualized and sensitive detection of bisphenol A (BPA). An open BPE with the molecularly imprinted polymers (MIPs) modified electron injection area and the Prussian blue (PB) coated electrochromic area was fabricated on an indium tin oxide (ITO) glass. A kind of Zr-based metal-organic framework (UiO-66) coated TiO 2 heterojunction (TiO 2 @UiO-66) was used for aptamer (Apt) immobilization and electron generation. BPA was selectively accumulated by MIPs, and subsequently recognized TiO 2 @UiO-66-Apt quantitatively, resulting in the formation of MIPs/BPA/Apt-TiO 2 @UiO-66 "sandwich" structure. Under UV-light, electrons were generated from the captured TiO 2 @UiO-66. For EC visualization measurements, electrons were injected into the PB film, causing a color change without an external power source. The extent of color change was proportional to the number of generated electrons, which correlated with the amount of captured BPA within a concentration range of 10−6–10−11 M. This allowed for the semi-quantification of BPA by naked eyes. For PEC detection, the BPE was used as the working electrode in a three-electrode system. The generated photocurrents signals could be digitally output for BPA with the concentrations ranging from 10−5 to 10−11 M. The SP-BPE sensors showed low background signal, improved selectivity and anti-interference abilities, and have demonstrated excellent performance in quantitative BPA analysis in water samples. They are particularly useful in scenarios where traditional power sources are limited or unavailable, and they offer opportunities for sustainable and environmentally friendly target detection. • An autonomous and sustainable sensing devices was developed based on self-powered open bipolar electrode. • Sandwich-type recognition model based on the dual-recognition of MIP and aptamer. • The visual and digital dual-mode enhanced flexibility, reliability, and user-friendliness. [ABSTRACT FROM AUTHOR]

Herein, borazine (B 3 N 3) assisted-oriented surface imprinted electrochemical sensor was designed for umifenovir (UMI) detection in serum and urine samples. An imprinted electrochemical sensor was developed via photopolymerization whereas butyl methacrylate monomer (BuMA) was selected as the functional monomer for coordinating the template molecules, UMI in the presence of B 3 N 3 as orientating UMI molecules between polymeric phase and the electrode surface. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to verify the electrochemical characterizations of the alterations at each step of the MIP production process. The created sensor was also characterized via contact angle, Fourier transform infrared spectrophotometry attenuated total reflection (FTIR-ATR), atomic force spectroscopy (AFM), and scanning electron microscopy (SEM) measurements. Furthermore, the electronic and molecular alterations on the electrode surface were assessed using quantum chemical calculations. Using differential pulse voltammetry (DPV) and EIS methods in standard solution and biological fluid samples, UMI was determined separately. The dynamic linear range of the designed sensor under optimized experimental conditions was found to be 0.50–7.50 pM and 0.25–5.00 pM for DPV and EIS methods, respectively. The developed sensor exhibited good recognition ability towards UMI molecules in the presence of its analogues as well as other interferents. As a result, the proposed sensors demonstrated excellent selectivity, high sensitivity, repeatability, and reproducibility performance for UMI analysis in commercial serum and urine samples. [Display omitted] • Borazine-assisted oriented surface imprinted developed for selective detection of UMI. • The analytical performance of MIP sensor was analyzed using DPV and EIS techniques. • The proposed sensor was applied to commercial serum and urine samples. • The sensor accuracy was evaluated using comprehensive computational design. [ABSTRACT FROM AUTHOR]

The development of point-of-use sensors capable of rapidly detecting per- and polyfluoroalkyl substances (PFAS) is crucial for real-time monitoring and effective management of PFAS contamination in the aquatic environment. Addressing current limitations in existing techniques for sensitive in-field analysis, this work employs a multifaceted approach to develop a rapid, ultra-sensitive, and single-step sensing platform for perfluorooctanesulfonic acid (PFOS). The approach integrates self-referencing interfacial capacitance sensing with microfluidic enrichment by AC electrothermal (ACET) effect. A molecular imprinted polymer (MIP) on gold interdigitated microelectrode chip is employed as a robust recognition element for the affinity-based capture of PFOS. A predetermined AC signal applied to the sensor will not only accelerate PFOS molecules towards the sensing surface for binding, but also track the interfacial capacitance change during binding, enabling real-time detection with extremely high sensitivity. The resulting single-step and rapid assay demonstrates detection as low as 0.5 fg/L (5×10−7 ppt) in 10 s, a linear range of 0.5–500 fg/L (5×10−7–5×10−4 ppt), and high selectivity (105:1) in Phosphate-buffered saline (PBS) media against other PFAS compounds including perfluorooctanoic acid (PFOA). The success of this work will potentially provide a routine PFOS monitoring test for drinking water. [Display omitted] • MIP and ACEK capacitive sensing combined for the first time. • A low detection limit of 0.5 fg/L in 10 s. • High selectivity with a ratio of 10⁵:1 against other PFAS compounds. • Field-deployment ready, one step operation, no external redox probe needed. • High potential for routine PFOS monitoring in drinking water. [ABSTRACT FROM AUTHOR]

A magnetically fixed bifunctional monomer molecularly imprinted electrochemiluminescence (ECL) sensor (MIP/MMOF@g-C 3 N 4 /L-Aas/MGCE) was constructed to selective detection thiabendazole (TBZ). Fe 3 O 4 modified by sulfonic acid group (–SO 3 H) acted as magnetic core to attract Co2+ to initiate the growth of ZIF-67 (MMOF). Graphitic carbon nitride nanosheets (g-C 3 N 4) were doped into MMOF by inherent amino groups to prepare integrated magnetic ECL luminophore (MMOF@g-C 3 N 4). MMOF@g-C 3 N 4 was immobilized on the surface of magnetic glassy carbon electrode (MGCE) by using the superparamagnetism of Fe 3 O 4 , which enhanced the stability and reusability of ECL system. Sodium ascorbate (L-Aas) acted as co-reactant accelerators to further enhance ECL intensity. MIP prepared with TBZ as template molecule and o-phenylenediamine (oPD)/resorcinol (RS) as bifunctional monomers contained more imprinting sites, which can enhance the adsorption performance. The luminescence mechanism of magnetic ECL system was investigated, and the specific recognition mechanism of MIP recognition system was deeply explored. The linear range of the method was 1 × 10−9–5 × 10−5 mol L−1, and the detection limit was 3.77 × 10−10 mol L−1. A good recovery rate (80.08%–96.82%) was obtained in the actual sample detection, which was basically consistent with the detection results of High Performance Liquid Chromatography. [Display omitted] • A novel magnetically fixed electrochemiluminescence sensor was constructed. • Sodium ascorbate was used as a co-reactant accelerator. • Bifunctional monomers molecular imprinting polymer was prepared. • The method for selective detection of thiabendazole was established. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymer (MIP-QDs) with fluorescence quenching ability toward propazine was synthesized for propazine detection. b(Blue)-MIP-QDs were prepared using ZnCdS/ZnS QDs via reverse micro-emulsion, whereas r(red)-MIP-QDs were synthesized using CdSe/ZnS QDs. By utilizing graphene quantum dots (GQDs) as a stable fluorescence intensity reference, the wide-gamut fluorescence test paper was constructed on the basis of mixing b-MIP-QDs, r-MIP-QDs, and GQDs under the optimal ratio. When analyzing spiked propazine in fish and seawater samples using a test paper, satisfactory recoveries of 104.0 %–114.6 % and 92.0 %–96.4 % were obtained, with corresponding limits of detection of 5.0 μg/kg and 1.0 μg/L, respectively. The RGB extractor was utilized to extract the actual fluorescence color and construct a dataset consisting of R, G, and B values, as well as concentration data from 400 samples. The SVR model of Python 3.9.7 was used to obtain and analyze the concentration and feature data. After optimization, the constructed model achieved a correlation coefficient of 0.98 and an RMSE of only 1.81, indicating high prediction accuracy and excellent generalization ability that meet quenching prediction requirements. As an intelligent and rapid detection method, this model holds significant practical significance. [Display omitted] • A wide-gamut fluorescence visual test paper was fabricated. • The visual test paper demonstrates excellent linearity, accuracy, precision, and sensitivity for promazine detect. • An RGB model by support vector machine were constructed. • The model exhibits high accuracy and strong generalization ability. [ABSTRACT FROM AUTHOR]

It is of great significance to explore a low cost and high sensitivity sialic acid (SA) detection method for early diagnosis and prognosis of cancer. Electrochemiluminescence (ECL) has aroused many scholars' interest in the accurate analysis of multi-domain analytes for its excellent performance. In order to improve the ECL signal strength and the corresponding detection sensitivity, it is effective to develop new ECL reagents. Copper nanowires (CuNWs) as luminophor has always been a blank in the field of ECL sensors. In this study, a glycosyl imprinted electrochemiluminescence sensor (GIP-ECLS) for SA specificity detection in serum was developed using CuNWs as luminophor. CuNWs can not only form quasi-three-dimensional (3D) conductive network, but also realize self-enhancement of ECL signal through Cu2+ and Cu+ conversion. In addition, the excellent conductivity and wrapping properties of Ti 3 C 2 provide a large electroactive area for electrode modification. More importantly, 3-aminobenzenoboric acid (3-ABA) specifically binds to SA to form B-N or B-O, which lays the foundation for selective recognition of SA. Under optimal conditions, the signal response of GIP-ECLS showed a good linear relationship with SA concentration at 5 × 10−12–1 × 10−8 mol L−1 (R 2 = 0.997), and the limit of detection (LOD) was 1.17× 10−12 mol L−1. The results showed that in the actual sample analysis, the recovery rate of SA detected by GIP/Ti 3 C 2 /CuNWs/GCE was good, and it had good selectivity and stability, which provided ideas for designing minimally invasive and highly sensitive detection of SA in serum samples. [Display omitted] • An ECL sensor system with high selectivity was constructed for the detection of SA. • CuNWs has been reported for the first time to achieve self-enhancing ECL signals. • Ti 3 C 2 provided an effective specific surface area for the loading of CuNWs. • Glycosyl imprinting based on borate bond improved the selective detection of SA. [ABSTRACT FROM AUTHOR]

A novel covalent organic framework and molecularly imprinted polymer (COF-MIP) composite, incorporating 1,1′-bis(allylcarbamoyl)ferrocene (AC-Fc) as a cross-linker, was synthesized through free radical polymerization for the ratiometric electrochemical detection of 5-hydroxytryptamine (5-HT). The AC-Fc cross-linker was synthesized using 1,1′-ferrocenedicarboxylic acid as a reactant. Subsequently, the COF-MIP was prepared using surface imprinting technique, employing AC-Fc as the cross-linker, COF as the supporter, and 5-HT as the template. The COF-MIP was employed in the development of a ratiometric electrochemical sensor for 5-HT. Upon 5-HT introduction, the peak current of 5-HT exhibited a concentration-dependent increase, while that for ferrocene (Fc) remained nearly constant. By utilizing Fc and 5-HT peak currents as reference and indicator signals, respectively, 5-HT was quantitatively determined. The ratio of I 5-HT /I Fc for the COF-MIP sensor was 4.69, 3.69, and 1.98 times higher than those of non-imprinted polymer (NIP), traditional MIP, and COF-NIP sensors, respectively. The ratiometric sensor with COF-MIP demonstrated a linear ratiometric signal (I 5-HT /I Fc) in response to 5-HT concentrations within the range of 0.2–10 µM, with a detection limit of 0.03 µM. The relative standard deviation of the non-ratiometric and ratiometric sensors was 8.7% and 2.7%, respectively. This methodology was successfully employed for the detection of 5-HT in human serum. [Display omitted] ● AC-Fc as an alkenyl ferrocene was synthesized with 1,1′-ferrocenedicarboxylic acid as a reactant. ● COF-MIP was synthesized with AC-Fc as cross-linker by free radical polymerization. ● COF-MIP was applied for ratiometric electrochemical detection of 5-hydroxytryptamine. ● Both the I 5-HT /I Fc and I 5-HT for COF-MIP/GCE were the highest among electrodes. ● The ratiometric strategy greatly improved the reproducibility of the COF-MIP sensor. [ABSTRACT FROM AUTHOR]

Rapid and sensitive determination of foodborne pathogenic bacteria at a low cost is crucial for ensuring food safety monitoring and diagnosing bacterial infections. In this protocol, we propose an electrochemical sandwich-type biosensor for highly sensitive detection of bacteria based on a bacterial imprinted polymer film (BIF) and metal-organic frameworks (MOF)-assisted redox recycling amplification. The BIF is formed in-situ through electropolymerization (EP) and template removal on the electrode surface, while aptamers are assembled on nanogold-modified MOF to create signal nanoprobes with target recognition ability. The BIF-modified electrode effectively captures the target bacteria and subsequently forms a sandwich structure through conjugation with signal nanoprobes, enabling efficient adsorption of methylene blue (MB). This facilitates the redox recycling of Fe(II) from the electroactive [Fe(CN) 6 ]3-/4- in testing buffer assisted by MB, thereby generating a significantly amplified anodic current of [Fe(CN) 6 ]3-/4- for precise quantitation. By utilizing the selective BIF interface and MOF-assisted redox recycling amplification, our method demonstrates excellent analytical performance with a low limit of detection (LOD) of 1 CFU mL−1, a broad detection range spanning from 10 to 108 CFU mL−1, and high selectivity. The feasibility of applying this approach for detecting bacteria in complex samples highlights its significant potential in areas related to food safety and public health. • A signal-on sandwich bacterial biosensor based on molecularly imprinted polymer was developed. • This study represented the initial report on enhancing the characteristic peak current of [Fe(CN) 6 ]3−/4− assisted by MB. • This method offers an economical and sensitive sensing platform without the need for complicated sample pretreatment. [ABSTRACT FROM AUTHOR]

Developing portable sensing platform with robust signal intensity is essential for on-site detection. Here, a bifunctional poly(o -phenylenediamine) (PoPD)-involved portable photoelectrochemical (PEC) sensor is proposed for detecting erythromycin (Ery). Firstly, the PoPD polymer-semiconductor acts as a molecularly imprinted polymer for specific recognition of Ery and simultaneously serves as a key PEC-active component for constructing WSe 2−x nanosheets/PoPD p–n heterojunction to enhance the PEC response. Secondly, a greatly simplified PEC sensing platform is developed utilizing a household flashlight and a lightweight U-disk workstation that connects to a smartphone via Bluetooth. The portable PEC sensor achieves high sensitivity with an excellent linear relationship in the range of 0.01–200 μM. It has a low detection limit of 3.9×10−3 μM (S/N = 3) and exhibits great stability, selectivity, and reproducibility. This work not only highlights the use of photoactive polymer semiconductors in the design of novel signal-enhancement PEC sensors, but also showcases an efficient portable sensing platform for potential on-site and real-time detection. [Display omitted] • PoPD serves as molecularly imprinted support and photoactive component of p-n heterojunction. • Proposing a portable PEC sensor utilizing household flashlight and U-disk workstation. • Achieveing a high sensitivity and potentials of on-site and real-time detection. [ABSTRACT FROM AUTHOR]

A novel imprinted material for glycoprotein detection was prepared based on metal-organic framework (MOF)/covalent-organic framework (COF) hybrid composite (MOF@COF-B(OH) 2) with fluorescent properties and boric component that facilitated glycoprotein imprinting. The MOF@COF-B(OH) 2 exhibited improved fluorescence emission from MOF due to efficient excited-state intramolecular proton transfer (ESIPT). Transferrin (TrF), an important transporting glycoprotein, was selected as the target. MOF@COF-B(OH) 2 effectively captured TrF through boronated affinity. The imprinted material (MOF@COF-B(OH) 2 @MIP) showed obvious fluorescence quenching after incubation with TrF at 430 nm via the photo-induced electron transfer (PET). A good linear relationship was demonstrated in the range of 0.1–40 µM with an associated limit of detection (LOD) of 57.6 nM under optimal conditions. An electrochemical platform for TrF detection was constructed by combining MOF@COF-B(OH) 2 @MIP with a disposable screen-printed carbon electrode (SPCE). The differential pulse voltammetry signal generated by MOF@COF-B(OH) 2 @MIP/SPCE served as a secondary signal to monitor TrF. The MOF@COF-B(OH) 2 @MIP/SPCE exhibited satisfactory linearity with a LOD of 2.7 nM. Moreover, the imprinted sensor showed good recovery rates for detection in actual samples using fluorescencent and electrochemical modes. This study offered a promising strategy for the application of boric acid-functionalized MOF@COF in glycoprotein sensing. [Display omitted] • A novel imprinted strategy based on MOF@COF-B(OH) 2 @MIP for glycoprotein was designed. • MOF@COF-B(OH) 2 was served as imprinted supporter and provided ideal imprinting environment. • Dual-mode sensing platform was constructed for sensitive and accurate detection of glycoprotein. • Boric acid-functionalized MOF@COF provided a new application in glycoprotein imprinting. [ABSTRACT FROM AUTHOR]

Deltamethrin (DEL), a synthetic pyrethroid insecticide, may have long-term adverse effects on the aquatic environment. Extreme Gradient Boosting (XGBoost) is a classic ensemble boosting algorithm framework known for its high training efficiency, strong prediction performance, and versatile applications. In this study, we successfully developed a highly sensitive molecularly imprinted fluorescence nanosensor (MF-sensor) for DEL determination, enhanced by the XGBoost algorithm. The MF-sensor was fabricated by grafting blue and red CdSe/ZnS quantum dots onto a molecularly imprinted silica layer. The MF-sensor consisted of blue-molecularly imprinted polymer (MIP)-quantum dots (QDs) and r-MIP-QDs, which selectively detected DEL, and unmodified green CdSe QDs, which were not selective for DEL. Under optimized conditions, we observed an excellent linear relationship between the I 526 /(I 450 + I 630) ratio and DEL concentration ranging from 0.01 mg/L to 40.0 mg/L (R2 = 0.9944). The limit of detection was determined to be 1.34 µg/L. The recoveries in actual samples ranged from 98.5% to 109.0%, with a relative standard deviation (RSD) below 7.5%. Additionally, we utilized the XGBoost algorithm to establish a DEL prediction model, achieving an accuracy of 95.7%. The recoveries ranged from 96.0% to 102.4%, with a RSD below 5.5%. Overall, the proposed MF-sensor, enhanced by the XGBoost algorithm, was successfully utilized for the detection of DEL in environmental and aquatic products. [Display omitted] • A tricolor MF-sensor with self-correction capability was fabricated. • MF-sensor can realize the visual detection of deltamethrin in complex samples. • XGBoost algorithm improves the detection accuracy of MF-sensor. • Rapid deltamethrin detection can be achieved by using smart phones. [ABSTRACT FROM AUTHOR]

Interleukin-6 (IL-6) is an important cytokine involved in immune responses and maintaining body homeostasis. Elevated IL-6 levels, exceeding ∼ 40 pg/mL in bodily fluids, are associated with inflammation and diseases such as COVID-19, cardiovascular disorders, and Alzheimer's, necessitating real-time health monitoring for personalized healthcare. In this study, we developed a highly sensitive and selective IL-6 sensing platform by depositing a poly(o -phenylenediamine) (P(o -PD))-based molecularly imprinted polymer (MIP) onto an oxygen-functionalized screen-printed carbon electrode with gold nanoparticles, 3-aminopropyltriethoxysilane (APTES), and glutaraldehyde (GA). While APTES enhanced the peak current due to redox probe adsorption, GA reduced it due to non-conductive aldehyde groups. This functionalized surface improved hydrophilicity due to the presence of amino and carbonyl groups. We identified that a 120-minute NaCl treatment effectively removed IL-6 templates, ensuring the successful embedding of IL-6 in the P(o -PD) matrix. We calculated an imprinting factor of 11.2, indicating the effective imprinting of IL-6 by P(o -PD) and the presence of IL-6 specific binding sites within the MIP, resulting in a robust current response to IL-6. After optimizing the MIP deposition through five cycles, we detected IL-6 concentrations ranging from 2 to 400 pg/mL, with a sensitivity of 3.48 μA/log(pg/mL) and a limit of detection of 1.74 pg/mL. When tested in real human serum, the sensor encountered challenges due to P(o -PD) matrix adsorbing other active molecules. Despite this challenge, our platform demonstrates high selectivity and long-term stability in IL-6 detection. These qualities position our sensor well-suited for point-of-care diagnostics, emphasizing its potential as a reliable tool for real-world applications. [Display omitted] • The sensor enables real-time IL-6 monitoring in serum, aiding early intervention in COVID-19, heart diseases, and Alzheimer's. • A stable electrochemical MIP sensor using P(o -PD) shows exceptional sensitivity for IL-6. • Electro-imprinting and Au nanoparticle integration enhances IL-6 binding, ensuring reliable sensing performance. • The MIP IL-6 sensor has high specificity and minimizes interference from BSA, HRP, AA, L-GA, and L-Cys. [ABSTRACT FROM AUTHOR]

In this paper, a turn-on fluorescence sensor (COF TPDD @ILMIPs) was prepared for the detection and removal of the α–dicarbonyl compound 3-deoxyglucosone (3-DG) in milk. The sensor uses ultra-high quantum yield green fluorescent covalent organic frameworks (COFs) as the fluorescence center, and introduces ionic liquids to improve its fluorescence performance and mass transfer rate, and the selectivity and anti-interference ability of the sensor were improved by molecular imprinted technique. In addition, the sensor was combined with a smartphone sensing platform to achieve real-time quantitative detection of 3-DG in the field. The quantitative detection of 3-DG in a good linear range (0.5–100 μg/L) was observed, and the low limit of detection was 0.31 μg/L. The spiked recoveries of 3-DG in milk samples ranged from 81.96–117.39 %, which provided an effective strategy for the accurate and rapid detection of hazardous substances in milk. [Display omitted] • A turn-on fluorescence sensor (COF TPDD @ILMIPs) was prepared for 3-DG on-site detection. • COF TPDD with ultra-high quantum yield was used as the fluorescence center. • Introducing ionic liquids to improve the fluorescence performance and mass transfer rate. • A COF TPDD @ILMIPs-based smartphone real-time quantitative platform was established. [ABSTRACT FROM AUTHOR]

Cholesterol is a crucial cellular molecule in the human body, and a neutral lipid necessary for maintaining the integrity and fluidity of cell membranes. Additionally, it acts as a precursor for the synthesis of essential substances for living organisms, including steroid hormones, bile acids and vitamins. Nonetheless, cholesterol is not always advantageous, and both excess and deficiency of cholesterol can result in serious diseases. Therefore, maintaining cholesterol at a normal level is of paramount importance for the maintenance of normal cellular activity. In this study, an amino-functionalized metal-organic framework (UiO-66-NH 2 , abbreviated as U6NH 2) was used as a carrier, on the surface of which gold nanoparticles (AuNPs) was embedded and cholesterol oxidase (ChOx) was immobilized, and then cholesterol was employed as a template molecule, followed by the synthesis of molecularly imprinted polymers (MIPs). Remarkably, the obtained U6NH 2 @AuNPs-ChOx@MIPs can be used to facilitate efficacious and selective detection of blood cholesterol through a facile colorimetric method over a range of 2.9 mM - 6.7 mM with a limit of detection (LOD) = 2.4 mM, while the normal level of blood cholesterol should be less than 5.18 mM. Moreover, the sensing system demonstrates excellent stability and satisfactory selectivity. The constructed cholesterol selective detection system reported in this paper is anticipated to have a crucial impact on bioanalysis. • The sensing system combining MIPs with the enzyme cascade catalytic system is successfully synthesized. • The combination of MOFs and MIPs overcomes the drawbacks of MIPs, which tend to deform and aggregate into dense clusters. • The sensing system could achieve a sensitive detection of cholesterol in the range of 2.9 mM - 6.7 mM with LOD = 2.4 mM. • The sensing system has excellent recyclability and stability, as well as excellent long-term storage stability. [ABSTRACT FROM AUTHOR]

Flavonoids benefits have rendered them interesting molecules in the realm of sensing. However, a significant challenge lies in their selective and sensitive detection in complex matrices. One of the most relevant flavonoids is rutin (RU), a flavonoid glycoside. In this work, a novel, straightforward, and green approach is proposed to prepare a selective molecularly imprinted membrane (MIM) for RU based on sodium alginate and polyvinylpyrrolidone, following a central composite design for the optimization of the MIM preparation. The developed membrane was characterized by Fourier transform infrared spectroscopy, thermo-gravimetric analysis, and scanning electron microscopy to assess the functional, thermal, and morphological properties of the membrane, respectively. The developed MIM was successfully applied for the selective and sensitive solid spectro-fluorescence sensing of RU within a concentration range of 0.01–10 µg/mL and a limit of detection (LOD) of 3.6 ng/mL. Furthermore, a new 3D-printed smartphone accessory was designed and applied in smartphone-based solid fluorescence assays. This innovation enabled portable, label-free, rapid, cheap, and green detection of RU across a concentration interval of 0.05–10 µg/mL, with a LOD of 20 ng/mL. Moreover, MIM showed important long-term stability and good reusability (10 regeneration cycles). Finally, the proposed methodology was validated using an accuracy statistical approach. Overall, this study didn't only demonstrate an innovative and straightforward approach to imprinting technology but also highlighted the promise of the proposed smartphone-based sensing method as a versatile tool with a broad range of applications to automatize the analysis and to enhance portable diagnosis technology. [Display omitted] • Green and straightforward preparation of an imprinted alginate membrane. • Relevant and rapid extraction of the template by the metal complexation. • Rapid, green, accurate, and direct fluorescence detection of rutin in foods. • Relevant selectivity, reusability, and applicability were achieved by the membrane. • On-site fluorescence sensing of rutin using a 3D-printed smartphone accessory. [ABSTRACT FROM AUTHOR]

Nanoplastics are widespread and pose a potential threat to human health. In this work, we designed a flexible multiscale cavity structured (MCS) surface-enhanced Raman scattering (SERS) substrate decorating Ni 3 S 2 nanocavity on a modified polyvinylidene fluoride (PVDF) microcavity. The dense two-dimensional Ni 3 S 2 nanosheets can provide a large surface area for the deposition of plasmonic silver nanoparticles (Ag NPs), increasing the density and strength of the "hotspots". Additionally, the nanocavity (width ∼500 nm), formed by the nanosheet surroundings, offers not only electromagnetic enhancement of the cavity mode for SERS but also a crucial detection site for nanoplastics attachment. This effectively addresses the challenge of SERS detection due to the scale mismatch between nanoplastics (>50 nm) and conventional "hotspots" (<10 nm). Moreover, the flexible imprinted PVDF microcavity endows the proposed substrate with omnidirectional "hotspots" enhancement, ensuring the signal stability and the feasibility of in-site detection of the actual sample. As a result, we achieved the successful in-site detection of polystyrene (PS) spheres of different sizes on the surface of oysters, with a detection limit of 10-3 mg/mL for 50 nm diameter. The flexible multiscale cavity SERS substrate is expected to show great potential in food safety and environmental monitoring. ● The substrate is excellent for both molecular and particulate detection. ● The substrate has excellent signal stability and abrasion resistance. ● MCS substrates show excellent results in the field detection of nanoplastics. [ABSTRACT FROM AUTHOR]

Herein, a spectrum-resolved differential strategy was proposed to enhance further the selectivity of photoelectrochemical (PEC) sensors, demonstrated by the simultaneous determinations of ascorbic acid (AA) and uric acid (UA). Molecularly imprinted polymer (MIP) membranes for AA (MIP AA) and UA (MIP UA) were fabricated on the surface of TiO 2 nanotubes via electropolymerization, using pyrrole as functional monomer, AA and UA as templates, respectively. It was shown that the increase in absorbance from AA or UA within the MIP membranes resulted in an intense decrease in the photocurrent of the PEC sensors. In the spectrum-resolved differential mode, Δ RI AA = (I AA / I AA0 − I UA / I UA0) 310 and Δ RI UA = (I UA0 / I UA − I AA0 / I AA) 275 were used in the simultaneous determinations of AA and UA, respectively. Where I AA , I AA0 , I UA and I UA0 are the photocurrents of MIP AA and MIP UA in sample and blank, the subscripts of 275 and 310 stand for the excitation wavelength (nm), respectively. The interference levels in the differential mode were reduced by one order of magnitude compared with the normal MIP mode. The spectrum-resolved differential PEC MIP sensors were used in the simultaneous determination of AA and UA in serum and urine samples, with the detection limits of 0.019 and 0.036 μM, respectively. [Display omitted] • Spectrum-resolved molecularly imprinted photoelectrochemical sensors were reported. • The wavelength-dependent photocurrent response was investigated. • Photocurrents at 275 and 310 nm were used to determine uric acid and ascorbic acid. • Interference to sensor A was corrected from sensor B at its insensitive wavelength. • The anti-interference ability of the sensor was much enhanced in differential mode. [ABSTRACT FROM AUTHOR]

The early detection of prostate cancer (CaP), one of the most common cancers in males, improves treatment efficacy. However, current methods to detect CaP are limited by specificity and sensitivity or require an invasive and unpleasant procedure. Therefore, there is a need for a novel, fast, and noninvasive CaP detection method. This proof-of-concept study aimed to diagnose CaP from urine samples by detecting the UV-induced fluorescent clusters formed in situ that reflect a urine composition specific to CaP patients using fluorescence spectroscopy. The UV-induced clusters formed upon irradiation by UV light with a wavelength of 254 nm were detected at excitation and emission wavelengths of 400 nm and 460 nm. Fifteen patients with CaP were correctly distinguished from 5 controls. The different stages of CaP could be further determined using molecular imprinting technology. Additionally, a paper-based analytical device was developed that enabled the correct identification of stage I cancer patients by fluorescent spectroscopy detection and the naked eye. In conclusion, this novel, easy-to-operate, point-of-care assay can enable early diagnosis of CaP with high accuracy and judgement of the disease stage. The simplicity, as well as versatility of the proposed method, will enable its application also to other diseases and disorders. • Easy-to-operate, point-of-care assay for diagnosis of prostate cancer from urine samples. • Prostate cancer detection with high accuracy and judgement of the disease stage. • UV-Induced fingerprint spectroscopy was combined with molecularly imprinted polymers. • Simple diagnostic by a paper-based analytical device was enabled. [ABSTRACT FROM AUTHOR]

Monitoring and quantifying organic chemicals in the environment play a vital role in understanding their behavior and ensuring environmental safety. MCPA (2-methyl-4-chlorophenoxyacetic acid) is a commonly used phenoxy herbicide that poses potential risks to aquatic life. In this study, we present an innovative analytical approach for MCPA quantification, employing molecularly imprinted polymers (MIPs) for selective extraction and ambient plasma mass spectrometry for direct on-line analysis. To synthesize functional MIPs, we employed a post-polymerization strategy based on a thiol-ene click reaction conducted on a short-chain poly[2-(3-butenyl)-2-oxazoline] (poly(ButenOx)) that allowed attachment of 3-mercaptopropionic acid (MPA) to polymer side chains. The incorporation of MPA groups into polymer structure enabled the attainment of elevated maximum adsorption capacities and enhanced selectivity towards MCPA. Utilizing a specially designed ambient plasma mass spectrometry setup, we successfully quantified MCPA in water samples, achieving significantly improved detection limits compared to conventional solution-based analysis, whereas the quantification of MCPA in real-life river water samples demonstrated excellent recoveries. In conclusion, this novel analytical method employing MIPs and ambient plasma mass spectrometry provides an effective and sensitive approach for accurate MCPA detection in environmental water samples. The technique holds promise for facilitating reliable monitoring and management of MCPA levels in aquatic ecosystems. [Display omitted] • Poly(ButenOx) was functionalized with 3-mercaptopropionic acid with click reaction. • The obtained materials were cross-linked to obtain MIPs imprinted with MCPA. • MIPs with the highest modification degrees showed the highest adsorption properties. • Ambient mass spectrometry was used to quantify the analate adsorbed by MIPs. • Real-life sample analysis proved applicability of the proposed analytical procedure. [ABSTRACT FROM AUTHOR]

The increasing abuse of various food additives has promoted concerns about food safety, necessitating accurate monitoring of their contents to ensure the standardized production of desserts. To address this issue, a molecularly imprinted gel (MIG) has been developed as an artificial antibody using the optimization of computational chemistry for the selective recognition of vanillin in desserts through an electrochemical strategy. Specifically, the food additive of vanillin is used as the template to connect with the optimal functional monomer methyl acrylamide and then MIG is obtained by the surface polymerization which is anchored on the surface of sea urchin-shaped biomimetic enzyme Co 2 NiO 4 @PtCu. This hydrophilic MIG has an unprecedented ability to selectively recognize vanillin in virtue of the optimization of density functional theory. The as-prepared Co 2 NiO 4 @PtCu-MIG serves as an artificial antibody and can be used to construct an electrochemical sensor for the selective detecting vanillin with a wide linear detection range of 50 nM to 500 μM and a low limit of detection of 3.45 nM. More importantly, this MIG-type artificial antibody could effectively monitor food safety by selectively recognizing vanillin in six desserts including wafers, biscuits, chocolate, puffs, and ice cream. [Display omitted] • First report on the selective recognition of vanillin by theoretically optimized MIT. • MIG is served as a vanillin molecule specific recognizer with enhanced selectivity. • DFT is used to screen functional monomers for the optimal specific recognition effect. • Sea urchin-like biomimetic enzymes Co 2 NiO 4 @PtCu offer much more active sites. • The selective recognition of vanillin in desserts is achieved by this sensor in food safety. [ABSTRACT FROM AUTHOR]

Developing new optoelectronic materials is the eternal pursuit and key strategy for building high-performance photoelectrochemical sensors. In this work, a novel organic polymer film containing D-A unit was firstly in-situ electro-synthesized on ZnS/rGO surface by using 9,9′-(9,9′-spirobi[fluorene]−2,7-diyl)-bis-9 H-carbazole (SFC) and carbazole as functional monomers. The micromorphology, element composition, structure, photoelectric efficiency and recognition ability of the key component and/or the sensing composite were investigated by SEM, XPS, XRD and transient photocurrent spectra, and the possible mechanism of charge carrier separation and transmission was proposed. Owing to the good light absorption ability, excellent film formation and imprinting ability, effective electrons-holes separation path, and satisfactory application stability, the prepared photoelectrochemical sensor exhibited good sensing performance for luteolin. Under the optimized conditions, the photocurrent intensity of the sensor showed a good linear relationship with the logarithmic concentration of luteolin from 0.001 μmol L−1 to 2 μmol L−1, with a detection limit of 0.35 nmol L−1 (S/N = 3). When applied in actual samples including carrot, peanut shells and chrysanthemum tea, highly consistent results with classical HPLC method were obtained. This work provided a new photoelectrochemical approach for the highly selective and sensitive detection of small molecules besides luteolin. • Commercial donor-acceptor molecule was firstly used in photoelectrochemical sensor. • Intramolecular electron-transfer path enhanced photoelectric conversion efficiency. • The MIP film possessed both recognition and photoelectric conversion capability. [ABSTRACT FROM AUTHOR]

Designing a polarity-switchable photoelectrochemical (PEC) sensor is important, but there are significant challenges due to the difficulty in adjusting the polarization of photoelectric or photoactive materials. In this manuscript, we established a simple and polarity-switchable molecularly imprinted polymer (MIP)-PEC sensor based on a "Z-scheme" strategy for detecting acrylamide (AM). First, we prepared a composite material of MoS 2 /rGO/Au (MGA) with a large specific surface area and good electrical conductivity that was sensitive to visible light. Second, the photoactive material MGA was used as the substrate material and polypyrrole (PPy) was acted as the functional monomer associated with the template molecule AM to construct the MIP working electrodes. PPy not only dressed up as a functional monomer but also as a polarity switcher, creating an in-situ-grown PPy/MGA heterojunction with a charge-carrier transport path similar to the letter "Z." The design of the Z-scheme strategy not only increased the signal intensity of the photocurrent but also switched the photocurrent polarity from the anode to the cathode, avoiding the interference of a false positive or a false negative. When using this PEC-MIP sensor for the quantitative detection of AM, the detection limit was 1.7 pmol for the linear range of 0.25–10000 nmol. The proposed sensor exhibited satisfactory sensitivity and selectivity, and it has great potential for monitoring emerging food safety risks. [Display omitted] • a polarity-switchable photoelectrochemical molecularly imprinted sensor was put forward. • Polypyrrole not only dressed up as a functional monomer but also as a polarity switcher. • The design of the Z-scheme strategy enhanced the photo-to-current conversion efficiency. • This photoelectrochemical sensor can prevent interference from false positives or false negatives. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) posed substantial safety risks in industrial settings due to its odorless and toxic nature and necessitated vigilant detection. With the burgeoning importance of H 2 S gas sensing applications, this study focused on the synthesis and utilization of a novel biomimetic material aimed at advancing gas sensing capabilities. Biomimetic polyaniline (Bio-PANI) with an artificial hierarchical surface structure was fabricated through the innovative nanocasting technique. This technique involved the replication of the surface pattern of a natural Xanthosoma sagittifolium leaf (XSL) onto a PANI coating, achieved using a negative template. In comparison to PANI, Bio-PANI showcased higher specific surface area (160 m2/g versus 41 m2/g of PANI) and exhibited significantly amplified reversible redox and doping–dedoping capacities. The application of Bio-PANI and PANI coatings on interdigitated electrodes (IDEs) allowed for gas-sensing assessments. These evaluations encompassed as-prepared IDE sensor's responsivity, selectivity, repeatability, and stability. Notably, the Bio-PANI-coated IDE sensor showed larger response (185% versus 27% of PANI toward a 10 ppm concentration of H 2 S), a consequence of their substantially larger specific surface area and greater electrochemical performances when contrasted with PANI-coated IDE sensor. In addition, Bio-PANI-coated IDE sensor exhibited better selectivity, repeatability, long-term stability, and moisture resistance. [Display omitted] • Surface of natural XSL was transferred onto PANI and first applied in gas sensor. • Bio-PANI-coated IDE sensor showed quicker and higher response compared to PANI. • Bio-PANI improved its redox ability and conductivity than PANI. [ABSTRACT FROM AUTHOR]

The combination of electrochemiluminescence (ECL) and molecularly imprinted polymer (MIP) techniques offers distinct for detecting organophosphorus pesticides (OPs). Herein, a novel flake-like nanocomposites Au@Cu:ZIF-8 was successfully synthesized, as to design a molecularly imprinted electrochemiluminescence (MIP-ECL) sensor for the detection of malathion (MAL). The doped Cu2+ as a co-reaction promoter facilitated the generation of the active intermediate SO 4 •− for the cathodic reaction system with K 2 S 2 O 8 as the co-reactant, while AuNPs were used as an excellent catalyst, further enhancing the ECL strength of the overall reaction system. Subsequently, MIP film was formed by the electropolymerization of Benzo[1,2-b:4,5-b′]dithiophene-4,8-dione as a functional monomer and MAL as a template molecule on the electrode surface. Confirmation of this process was achieved through molecular docking technique, which indicated that template molecule and functional monomer were tightly bound through non covalent bonds. The ECL signal was controlled by the elution and incubation of MAL by the MIP, thus establishing a novel method for MAL detection. The sensor showed a good linear relationship in the range of 10 pg/mL to 0.1 μg/mL with a detection limit of 0.18 pg/mL (S/N = 3). Furthermore, the recoveries of MAL detection in apple, cabbage and tomato samples ranged from 91.94% to 104.50%, indicating that the sensor offers potential applications for trace analysis of OPs in food and agricultural products. [Display omitted] • A molecularly imprinted electrochemiluminescence sensor for the detection of malathion was developed. • Co-reaction promoter and noble metal nanoparticles increased sensitivity of sensor. • Interactions between template molecules and functional monomers were verified by molecular docking technique. • Molecularly imprinted polymer exhibited excellent selectivity for malathion. • The linear detection range was 10 pg/mL to 0.1 μg/mL with a detection limit of 0.18 pg/mL. [ABSTRACT FROM AUTHOR]

In this study, a new electrochemical sensing strategy is presented for amitriptyline (AMT) by a molecularly imprinted polymer/NiCo 2 O 4 (MIP/NCO) as an electrode modifier on a carbon cloth (CC). The AMT/imprinted polymer ratio was first optimized by means of the density functional theory (DFT) model. The successful formation of the electrode materials was assessed via several characterizations such as X-ray diffraction and Fourier transform infrared spectroscopy. The findings confirmed the nearly complete extraction of the template from the polymer network. The electrochemical properties of the eluted MIP/NCO/CC (EMIP/NCO/CC) were also appraised using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The constructed sensor demonstrated the superior detection efficiency towards the oxidation of AMT in phosphate buffer solution (PB, pH =7) with a broad linear range from 0.01 μM to 1 μM, a high sensitivity of 58 µA/µM cm2, and a low limit of detection of 2.39 nM. The interfering agents had no significant influence on the detection of AMT. The analysis of AMT in real samples yielded satisfactory results as well. This electrode was particularly well-suited for prospective applications in drug determination owing to its great sensitivity, easy regeneration, and modification with EMIP/NCO. • Improvement of an electrochemical assay based on molecularly imprinted polymers (MIPs). • A novel eluted MIP/NiCo 2 O 4 /carbon cloth (EMIP/NCO/CC) is fabricated for the selective detection of AMT. • AMT-MIP fabrication was optimized by the density functional theory (DFT) model. • The sensor indicates a detection ranging from 0.01 μM to 1 μM with a LOD of 2.39 nM. • The proposed route was applied in human serum satisfactorily. [ABSTRACT FROM AUTHOR]

Neurodegenerative disorders necessitate early detection for timely diagnosis and treatment. Here, we present an electrochemical sensor comprising a robust biomimetic receptor, a molecularly imprinted polymer (MIP), integrated with a system of thin film metal electrodes for rapid detection of brain-derived neurotrophic factor (BDNF) as a potential neurodegenerative disorder biomarker. The MIP-based sensor utilizes the surface imprinting approach, where controlled polymer growth around the protein template creates geometrically-fit imprinted sites on the receptor surface. Following thorough characterization, the performance of the sensor was studied by differential pulse voltammetry. Under optimal conditions, the sensor exhibits an impressive limit of detection of 9 pg/mL for BDNF, showing over 5-fold selectivity against closely related neurotrophic factor proteins (CDNF and MANF) and 30-fold selectivity against proteins with similar pI values (e.g., CD48). Competitive binding assays further confirmed the sensor's selectivity, with BDNF inhibiting the binding of interfering proteins. Successful validation of BDNF detection in complex biological samples, specifically fetal bovine serum, highlighted the sensor's potential for real sample analysis. Compared to conventional biosensors, the presented strategy could unlock a new route to develop a highly desirable, robust sensing platform with strong affinity, specificity, and cost-effectiveness for diagnosing neurodegenerative disorders. [Display omitted] • An electrochemical sensor for brain-derived neurotrophic factor (BDNF) was developed. • Molecularly imprinted polymer endowed selectivity to BDNF was used as a robust recognition element of the sensor. • Sensor selectivity to BDNF was confirmed by carefully designed competitive and non-competitive binding assays. • The feasibility of the sensor to detect BDNF was established in complex real-world biological media. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence (ECL) sensing by virtue of its low background interference and great controllability, has emerged as a significant method in analysis. However, how to gain well-performed ECL sensors in a facile effective way remains a challenge. Herein, we synthesized [Ru(bpy) 3 ]2+ doped mesoporous carbon nanospheres (RMCNs) as an enhanced ECL luminophore via a one-step approach, which present great ECL emission and stability. The synergistic effects of [Ru(bpy) 3 ]2+ doping level, Zeta potential, pore size and particle size of RMCNs on the ECL intensity were systematically studied, and the ECL efficiency of individual [Ru(bpy) 3 ]2+ cation in RMCNs was clearly clarified through approximate calculation. Combined with molecularly imprinted polymer (MIP), an ECL sensor featuring good selectivity and wide detection range was developed for the detection of β -hydroxybutyric acid (0.1 nM∼10 mM). This work puts forward an effective solution for the design of nanoluminophores with excellent and stable ECL property. • RMCNs were synthesized by one-step approach, ensuring stability and high intensity. • The synergistic effects of [Ru(bpy)3]2+ doping level, Zeta potential, pore size and particle size of RMCNs on the ECL intensity were illustrated. • The developed sensor can detect β -HB in a wide range, which can fully cover the range of human β -HB physiological concentration. [ABSTRACT FROM AUTHOR]

For glycoprotein detection that is both specific and sensitive in clinical diagnosis and treatment, it is necessary to develop artificial bionic recognition materials. By integrating boronate affinity controllable oriented surface imprinting with carbon nanofibers (CNF) as self-supported electrodes, a simple and cost-effective method for preparing glycoprotein-imprinted self-supported electrochemical biosensors was presented in this paper. The molecular imprinted polymers (MIPs) electrode based on Co, Mo 2 C-CNF was prepared in the presence of horseradish peroxidase (HRP) as a model glycoprotein by cyclic voltammetry. The CNF mats, composed of Co and Mo 2 C nanoparticles encapsulated in carbon nanofibers (Co, Mo 2 C-CNF) via electrospinning, could offer more electrical conductivity and active sites for the detection process. The results demonstrated that the hybrid structure of Co, Mo 2 C-CNF and MIPs exhibited high specificity and excellent selective recognition efficiency for HRP. The detection limit was obtained as 7.4 fg mL−1. The developed biosensor was applied to detect HRP in human serum with a recovery ranging from 89.21 % to 116.68 %. The developed MIPs electrochemical sensor has great potential for developing highly sensitive and specific glycoprotein imprinting biosensors. [Display omitted] • Co, Mo 2 C-CNF via electrospinning had excellent electrochemical performance. • Co, Mo 2 C-CNF had been utilized to develop a glycoprotein imprinted self-supported biosensor. • MIPs were fabricated by an in-situ electrochemical polymerization strategy. • The developed self-supported biosensor exhibited high selectivity towards the templates. [ABSTRACT FROM AUTHOR]

• An electrochemical sensors for detection of condensed lignin is developed. • The sensor is based on a molecularly imprinted conducting polymer (MICP). • The MICP is prepared by electropolymerization in presence of a template molecule representing condensed lignin. • Binding of the template molecule was verified by molecular modeling. • The MICP responds to the template molecule at micromolar concentration. Condensed lignin is an undesired byproduct that has detrimental effects in cellulose pulping processes, increasing the consumption of bleaching chemicals and altering the properties of main products. A simple method for quantification of condensed lignin could greatly improve the performance and economy of pulping mills. In this work, a chemical sensing material based on a molecularly imprinted conducting polymer was synthesized by using a marker of condensed lignin as template molecule. Molecular modeling was used as an essential tool to understand and optimize the complexation of the functional monomers with the template in order to improve the synthesis strategy. The imprinted polymer was synthesized by co-electropolymerization of 3,4-ethylenedioxythiophene (EDOT) and 3-acetic acid thiophene (AAT) in presence of 2,2'-methylenebis(2-methoxy-4-methylphenol) as template, and studied by cyclic voltammetry and electrochemical impedance spectroscopy. The anodic peak current at +0.88 V (vs. Ag/AgCl/KCl 3 M) in the cyclic voltammograms of the imprinted polymer sensor was used to detect the lignin marker dissolved in pure solvents at concentrations ranging from 1 × 10−6 to 1 × 10−2 M. [ABSTRACT FROM AUTHOR]

• Molecularly imprinted polymer based biosensing device was developed for localized detection of cytokines. • The device can detect IL-1β with low detection limit of 10.2 pg mL−1, and a linear detection range of 25–400 pg mL−1. • The stainless steel based sensing device is reusable and universal for detection of a spectrum of analytes. A molecularly imprinted polymer (MIP) based biosensing device on stainless steel (SS) for detection of locally variable concentration of cytokine interleukin-1β (IL-1β) was successfully developed using a sandwich assay scheme. The SS surface was firstly modified with a layer of polydopamine (PDA) followed by the attachment of a layer of poly(ethyleneimine) (PEI) by electrostatic adsorption. Subsequently, the template protein IL-1β was adsorbed on the PEI terminated SS surface due to electrostatic adsorption. A PDA imprinting film was then in-situ synthesized on the surface of the modified SS substrate with incorporated template cytokine. Finally, the template was washed off the SS substrate leaving behind cavities with specific shape and capable of capturing cytokines thus forming a MIP biosensing interface. After exposure to the analyte IL-1β, the MIP biosensing device was incubated with IL-1β detection antibody-modified fluorescent polystyrene beads allowing to determine the amount of captured IL-1β based on fluorescence intensity. The device has been demonstrated to detect IL-1β with low detection limit of 10.2 pg mL−1, and a linear detection range of 25–400 pg mL−1. This MIP biosensing device can be regenerated more than three times with coefficient of variation 2.08%. The device was applied for the detection of IL-1β secreted by rat macrophages, where the good specificity and selectivity were achieved. MIP serves in this device as a superior substitute of antibody with exceptional stability and reusability. The MIP based biosensing technology presented in our work paves a new way for developing a universal and robust sensing platform for the detection of spatially localised small proteins with low physical concentration. [ABSTRACT FROM AUTHOR]

A molecularly imprinted polymer (MIP) was electropolymerized on carbon nanoparticles modified electrode using aloe-emodin (AE) as template to fabricate a novel electrochemical sensor. The added thionine (TH) in solution played smart double roles for AE selective and sensitive detection. As an analogue of AE, TH can be adsorbed into imprinted cavities to arouse itself reduction peak current (i TH) due to the very similar structures between thionine (TH) and AE. The adsorbed TH can be further replaced by AE to decrease the current of TH and increase the current of AE (i AE). Thus, a current ratio of i AE / i TH was employed for AE sensitive detection with good selectivity. • Double roles of analogue and electroactive probe were played by the adsorbed TH during the replacement process. • As an analogue, adsorbed TH was replaced by AE in imprinted cavities, demonstrating the good selectivity of the sensor toward AE. • As an electroactive probe, decreased TH current and increased AE current were combined as a ratiometric signal for AE sensitive detection. • The feasibility of replacement was predicted by the computational simulation. • The electroactive probe with double roles may provide a new avenue for electroactive species ratiomentric detection. Molecular imprinted polymer (MIP) has been employed for electrochemical sensor preparation with good selectivity. However, to restrict the non-specific adsorption, the conductivity of MIP is usually unsatisfying, which limits its sensitivity for template detection. To achieve both of selectivity and sensitivity, a MIP electrochemical sensor was designed and fabricated by the electropolymerization of pyrrole in the presence of aloe-emodin (AE, template molecule) on carbon nanoparticles modified electrode in this work. Thionine (TH), being added in solution in advance, played double roles for AE recognition and detection. As an analogue of AE, TH was adsorbed into imprinted cavities and then was replaced by AE, indicating the good selectivity of the sensor. This replacement of TH by AE was also demonstrated by the result of computational simulation. As an electro-active probe, the peak current of TH decreased and peak current of AE increased based on the replacement of TH by AE. A current ratiometric signal defined as |Δ i AE |/|Δ i TH | was used for AE sensitive detection. Thus, the replacements of TH by AE demonstrated that the sensor possessed high sensitivity and good selectivity. A linear range of 1.0 × 10−7 -1.0 × 10-4 mol/L for AE detection was obtained with a limit of detection of 7.5 × 10-8 mol/L. And the sensor has been applied to analyze AE in real samples with satisfactory results. The simple, smart, and effective strategy presented in this work can be further used to prepare electrochemical sensors for other compounds selective recognition and sensitive detection. [ABSTRACT FROM AUTHOR]

• A QCM sensor based on AuNPs doped molecularly imprinted layer and COFs-AuNPs composite was developed. • The sensitive and selective detection was attributed to the employment of COFs-AuNPs and crosslinked imprinting recognition sites. • The COFs-AuNPs composite and three-dimensional structure of imprinted matrix provided more recognition sites for sensing. In this study, for the first time a quartz crystal microbalance (QCM) sensor based on gold nanoparticles (AuNPs) doped molecularly imprinted layer and covalent organic frameworks composite (COFs-AuNPs) was developed for the detection of aflatoxin B1. The AuNPs doped molecularly imprinted layer involved in the crosslinking of o- aminothiophenol functionalized AuNPs (o- ATP@AuNPs) in the present of the templates on electrode surface. The imprinting recognition sites obtained by eluting the templates from imprinted polymer of poly(o- ATP) with AuNPs formed the specific three-dimensional imprinted contours toward the targets. A kind of porous lightweight material–CTpBD COFs and AuNPs were employed jointly to yield the COFs-AuNPs composite which provided large surface area for o- ATP@AuNPs crosslinking. The introduction of COFs-AuNPs substrate and three-dimensional structure of imprinted matrix endowed the sensor with more recognition sites. The sensitive and selective detection was attributed to the loading capacity of the COFs-AuNPs composite and the specific recognition effect of molecularly imprinted polymer of poly(o- ATP) with AuNPs. Under optimal conditions, the proposed sensor showed a wide linear range from 0.05 to 75 ng mL−1, low limit of detection (LOD = 2.8 pg mL−1) and the acceptable recoveries (87.0%−101.7%) in real samples analysis. [ABSTRACT FROM AUTHOR]

• A novel MIP/perovskite CsPbBr 3 QDs fluorescence sensor for phoxim detection. • A siloxane functional monomer with two kinds of functional groups has been synthesized. • The MIP/QDs were synthesized by slowly hydrolyzing the organosilicon monomers in situ. • The QDs were encapsulated in an imprinted silica matrix, which improved the stability of the QDs. In spite of the high-brightness of perovskite quantum dots (QDs), their instability and sensitive to oxygen and moisture are still major challenges that obstruct their analytical applications. This work demonstrates the fabrication and application of perovskite CsPbBr 3 QDs embedded in a molecularly imprinted polymer (MIP) for specific and sensitive detection of phoxim in real samples. CsPbBr3 QDs were obtained via a simple and convenient hot injection method. Based on the chemical structure of phoxim, we designed and synthesized a siloxane functional monomer with multiple functional groups to allow various types of interactions with phoxim. Next, the MIP/QDs composites were synthesized by slowly hydrolyzing the organosilicon monomers in situ. The obtained MIP/QDs composites possessed excellent selectivity for phoxim, and the imprinting factor of the optimized MIP/QDs was 3.27. Compared with previous studies regarding the detection of organophosphorus pesticides, the MIP/QDs fluorescence sensor exhibited high sensitivity and specificity. Under optimal conditions, the fluorescence quenching of the MIP/QDs had a good linear correlation for phoxim in the concentration range of 5–100 ng/mL, and with a limit of detection of 1.45 ng/mL. Finally, the method was used for the detection of phoxim in potato and soil samples, achieving recoveries of 86.8–98.2%. [ABSTRACT FROM AUTHOR]

• The MIPs and hydrophobic materials were prepared and combined via a simple way. • Hexanal detection in the range of 1–80 ppm was achieved. • Hexanal amounts in real samples were detected by the as-prepared gas sensor and validated by GCMS. Hexanal is a specific volatile organic compound (VOC) for monitoring the quality of various agricultural products and a biomarker for diagnosing lung cancer of human beings. However there is no existing hexanal gas sensor with high sensitivity and selectivity for hexanal detection in the presence of water vapor. Addressing this challenge, a quartz crystal microbalance (QCM) gas sensor modified with a hydrophobic molecularly imprinted polymers (MIPs) composite for hexanal detection was reported. Hexanal could selectively bind with the MIPs through hydrogen bonding while the hydrophobic silica nanoparticles could give the electrode resistant to water vapor. The QCM gas sensor showed the highest response to hexanal among the other tested vapors, and had little responses towards TMA, NH 3 , ethanol, acetone, acetic acid and diethyl ether. Octanal reached the second place followed by nonanal, but they two caused much less frequency shifts than that of hexanal. The QCM gas sensor was reliable for hexanal detection in the range of 1–80 ppm and able to detect hexanal amount from about 14.1 ppm–27.3 ppm in grass carp fillets with about 80% relative humidity in 7 days. The results displayed positive correlation with the solid phase micro extraction-gas chromatography mass spectrometer (SPME-GCMS) analysis of the same grass carp fillets samples, and the correlation coefficient was 0.98. It may offer some new ideas for gas sensors development with high sensitivity and selectivity in areas of quality evaluation of agricultural products and health evaluation of human beings. [ABSTRACT FROM AUTHOR]

• Electroanalysis of ecstasy (MDMA) using screen-printed carbon electrodes (SPCEs). • Molecularly imprinted polymers (MIPs) were developed for MDMA. • The polymerization of o -phenylenediamine (o -PD) and its interaction with MDMA was simulated by DFT methods. • The SPCE-MIP selectively analysed MDMA by square-wave voltammetry (SWV). • First time a SPCE-MIP sensor was developed for MDMA. This study demonstrates the ability of an electrochemical sensor based on molecularly imprinted polymers (MIPs) to selectively quantify 3,4-methylenedioxymethamphetamine (MDMA), also known as ecstasy, in biological samples. The device was constructed using ortho -phenylenediamine (o -PD) as the MIP's building monomer at the surface of a screen-printed carbon electrode (SPCE). The step-by-step construction of the SPCE-MIP sensor was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Density functional theory (DFT) calculations and modelling were performed not only to understand template-monomer interaction but also to comprehend which possible polymer structure - linear or ramified poly(o -PD) – indeed interacts with the analyte. The prepared sensor worked by directly measuring the MDMA oxidation signal through square-wave voltammetry (SWV) after an incubation period of 10 min. Several parameters were optimized, such as the monomer/template ratio, the number of electropolymerization scanning cycles, and the incubation period, to obtain the best sensing efficiency. Optimized sensors exhibited suitable selectivity, repeatability (2.6%), reproducibility (7.7%) and up to one month of stable response. A linear range up to 0.2 mmol L−1 was found with an r2 of 0.9990 and a limit of detection (LOD) and quantification (LOQ) of 0.79 and 2.6 μmol L−1 (0.15 and 0.51 μg mL−1), respectively. The proposed sensor was successfully applied to human blood serum and urine samples, showing its potential for application in medicine and in forensic sciences. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Surface-initiated PAA nano film grown on Ni-rGO-polymer by electro-polymerization. • PAA was used for the selective measurements of glucose for the first time. • Exhibited high sensitivity (1724.58 μA mM−1 cm-2) and LDL (0.0126 mg dL−1). • Successfully tested in the clinical samples. Abstract In this study, we have developed a non-enzymatic electrochemical biosensor for glucose, which shows fast response, reproducibility, high selectivity and sensitivity. Reduced graphene oxide (rGO) and Ni-nanoparticles were in situ dispersed in melamine-novolac polymer. The prepared novel Ni-rGO/P composite was used as the working electrode. Polyacrylamide (PAA) nano film was grown for the first time on the Ni-rGO/P substrate via electro-polymerization and used for the selective recognition of glucose. Melamine served as the source of the electro-conductive N heteroatom in the material. Tested using differential pulse voltammetry, PAA-Ni-rGO/P showed remarkable linearity (R2 = 0.99; S/N ratio = 3) over 0.03–250 mg dL−1 of glucose concentrations, with high sensitivity (1724.58 μA mM−1 cm-2) and low detection limit (0.0126 mg dL−1). The sensor also exhibited high reproducibility (up to ˜500 consecutive tests, RSD < 5%) and a good recovery. With negligible effects of the interfering bio-molecules (uric acid, ascorbic acid, cholesterol, etc.) on the sensor response, applicability of the present sensor was successfully tested (RSD < 6%) in a clinical setting. The approach described in this study can be used to electrochemically grow similar macromolecules as the recognition elements for different biomarkers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A MIPs based biosensor was designed to perform the determination of HSA. • PTH-MB and AuNPs were utilized to improve the sensitivity of the biosensor. • The biosensor possesses favorable selectivity, reproducibility and stability. • The strategy was applied for the determination of HSA in the actual urine sample. Abstract The detection of albumin in urine is of great significance for the early diagnosis and treatment of diseases. Herein, a molecularly imprinted electrochemical biosensor was designed for the detection of human serum albumin (HSA) in urine based on dual-signal strategy. The gold electrode (GE) was orderly modified by Au nanoparticles (AuNPs), polythionine-methylene blue (PTH-MB) and molecularly imprinted polymers (MIPs). The MIPs were synthesized through electro-polymerization, which utilized HSA as the template, and employed o -phenylenediamine (o -PD) and hydroquinone (HQ) as the functional monomers. The biosensor showed dual-signals at 0.20 V and −0.22 V corresponding to Fe(CN) 6 3−/4− and PTH-MB, respectively. When HSA was captured on the MIPs, the dual-signal simultaneously decreased. Both of the current signals of the substrate probe PTH-MB (ΔI substrate) and the solution probe [Fe(CN) 6 ]3-/4-(ΔI probe) were converted before and after the incubation of target HSA. The sum of the signal conversions ΔI D (ΔI substrate +ΔI probe) was utilized to quantify the target amount. Under the optimal conditions, the proposed biosensor exhibited a linear regression equation in the concentration range from 1.0×10-10 to 1.0×10-4 g L-1, with a low detection limit of 3.0×10-11 g L-1 (S/N=3). Furthermore, the prepared biosensor was employed for the determination of albumin in urine with satisfied selectivity and reproducibility. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Molecular imprinting approach used for simultaneous determination of RIF and INZ. • Fabrication of a dual template MIP sensor based on Cu-MOF/MC/GCE. • Highly sensitive determination of RIF and INZ with LODs in nanomolar range. • Successful determination of RIF and INZ in complex real samples. Abstract A highly sensitive and selective doubly imprinted polymer modified electrochemical sensor based on copper metal organic framework/mesoporous carbon (Cu-MOF/MC) composite was developed for simultaneous determination of Rifampicin (RIF) and Isoniazid (INZ). The molecularly imprinted polymer (MIP) film was formed on the surface of Cu-MOF/MC modified glassy carbon electrode (GCE) by incorporating RIF and INZ as template molecules during electropolymerization of pyrrole, followed by removal of both the template molecules. During this process of sensor fabrication, large numbers of complementary binding sites for template molecules are created on the surface of MIP sensor due to high surface area offered by Cu-MOF/MC composite. Various parameters influencing the performance of MIP sensor such as number of electropolymerization cycles and template: monomer ratio were optimized during the study. Based on the optimized parameters, the electrochemical response of Cu-MOF/MC/MIP/GCE towards determination of RIF and INZ was studied in a wide linear working range of 0.08 μM to 85 μM employing adsorptive stripping differential pulse voltammetry in aqueous as well as real samples. The limit of detection was found to be 0.28 nM and 0.37 nM for RIF and INZ respectively. In addition, the MIP sensor showed good stability, acceptable reproducibility and high selectivity for RIF and INZ over other common interferents. Moreover, the developed sensor was successfully applied for simultaneous determination of RIF and INZ in pharmaceutical formulations, blood serum and urine samples with satisfactory recoveries. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Application of suspension polymerization method for preparing MIP-MWCNTs nanocomposite for the first time. • The first electrochemical sensor based on MIP-MWCNTs nanocomposite for chlorpromazine (CPZ) drug. • The handmade screen printed carbon electrodes (SPCEs) with desired properties. • Long-term stability, high selectivity, good repeatability, low cost, and fairly fast response time of proposed sensor. • Successful application of the proposed sensor for CPZ determination in tablet and Human urine samples. Abstract In this research, the suspension polymerization method was used for synthesis of the nano-composite between Molecularly Imprinted Polymers (MIP) and Multiwall Carbon Nanotubes (MWCNT) for the first time. The chlorpromazine (CPZ) drug was applied as template molecule. The MIP-MWCNT nanocomposite and the non-imprinted polymer (NIP-MWCNT) were used for modification of screen printed carbon electrodes (SPCEs) which were designed and manufactured by hand. The modified SPCEs were used for CPZ determination via a three-step procedure includes: CPZ extraction from sample solution, electrode washing and electrochemical measurement. After ensuring the appropriate response of MIP based sensors to CPZ, the factors affecting the performance of sensor were examined and the calibration curve was constructed under optimized conditions. The peak current showed a linear relationship with CPZ concentration in the range of 7.50 × 10−10–2.50 × 10−7 M (R2 = 0.9956) and the detection limit was calculated 2.96 × 10−10 M. The relative standard deviations for investigation of sensor's repeatability and reproducibility were obtained 3.76 and 4.13% (n = 5) respectively. Finally, in order to evaluate the sensor's ability to determination of chlorpromazine in samples with complex matrices, it used for assay of CPZ in tablet and spiked human urine samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Molecularly imprinted polymer decorated 3D-framework of f MWCNTs was synthesis. • Fabricated electrochemical sensors were applied for Norfloxacin determination in pharmaceutical formulations and rat plasma. • The sensors show low detection-limit, wide linear-range and high selectivity for Norfloxacin detection. Abstract In this work, a 3D-framework of functionalized multi-walled carbon nanotubes (f MWCNTs) decorated with molecularly imprinted polymer (MIP), has been fabricated to achieve fast and ultrasensitive electrochemical molecular sensing. The cavity networks of MIP layer from Norfloxacin (NFX) molecules offers simultaneous identification and quantification of NFX; and thus, ensures its high selectivity. The porous structure of f MWCNT 3D-framwork effectively increases the specific surface area, and the copolymer of f MWCNTs and MIP shows synergistic effect for electrocatalytic reaction of NFX at the modified sensor. Under optimized conditions, the fabricated sensors show wide linear detection ranges of 0.003-0.391 μM and 0.391–3.125 μM, low limit of determination (LOD) of 1.58 nM, and excellent selectivity in discriminating NFX according to its structural analogues and possible interferences. Precise and fast quantification of NFX in pharmaceutical formulations (Yunnan Baiyao and Ouyi Pharmaceutical) and rat plasma samples (N = 4) suggests its simplicity and reliability. The recoveries from pharmaceutical formulations ranged from 97.36 to 109.58% with the precisions (relative standard deviations, RSD, n = 3) of 1.74–3.41%; and the recoveries from rat plasma samples ranged from 83.00 to 115.67% with RSDs (n = 3) of 0.45–10.30%. Considering the advantages of easy fabrication, and selective and sensitive detection, such sensors with different types of MIPs would be widely applied in the fields of pharmaceutical analysis, and environmental and clinical therapeutic drug monitoring. [ABSTRACT FROM AUTHOR]