Search

Glycoproteins play vital roles in living organisms and often serve as biomarkers for some disease. However, due to the low content of glycoprotein in biological fluids, selective detection of glycoproteins is still a challenging issue that needs to be addressed. In this study, molecularly imprinted colloidal array with multi-boronic acid sites for glycoprotein detection under physiological pH was proposed. Monodispersed glycoprotein imprinted particles (SiO2@PEI/MIPs) was first prepared based on surface imprinting strategy using horseradish peroxidase (HRP) as template, and polyethyleneimine (PEI) was used to increase the number of boronic acid groups. The binding experiment indicated that the SiO2@PEI/MIPs hold satisfactory adsorption capacity (1.41 μmol/g), rapid adsorption rate (40 min) and preferable selectivity toward HRP. Then the SiO2@PEI/MIPs was assembled into close-packed colloidal array to construct a label free optical sensor (denoted as GICA). Benefiting from the high ordered photonic crystal structure, binding of HRP onto the GICA could be directly readout from the changes in structure color and diffracted wavelength. The structure color of the GICA changed from bright blue to yellow with the diffraction wavelength red shifted 59 nm when the HRP concentration increased from 2.5 to 15 μmol/L. Importantly, the GICA was capable of detecting HRP from human serum samples. All those results indicated the potential of the GICA for naked-eye detection of glycoprotein.

Here, the graphene oxide (GO)/SiO2-loaded dual-imprinted membranes (GS-DIMs) were constructed based on the self-polymerization imprinting technique of dopamine, in which a twice polydopamine (PDA)-based imprinting strategy had been successfully developed to obtain the three-dimensional nanocomposite membrane-based separation system. Meanwhile, the pollution-intensive antibiotics of tetracycline (TC) was used as template molecule throughout the GS-DIMs synthesis, and the dopamine molecules were simultaneously used as functional monomer and cross-linking agent during the twice polydopamine (PDA)-based imprinting processes. Therefore, dual-TC-imprinted sites had been prepared based on the as-designed dual imprinting processes, the as-prepared GS-DIMs-based separation system with dual-TC-imprinted structures could not only allow for the largely enhanced rebinding result of 65.61 mg/g and faster adsorption equilibrium rate within 20 min, but also facilitate the permselectivity performance from TC-based complex separation system and mimetic water sample. Importantly, we demonstrated the applications and effects of the dual-imprinted membrane-based separation materials to selective rebinding and separation of TC from complex solution systems and mimetic water samples. The as-obtained permselectivity factors (β) around 4.0 strongly illustrated the efficiently selective separation ability and high-intensitive recognizability of TC than any other non-template molecules based on our GS-DIMs-based separation system. Overall, the as-designed GS-DIMs had great potential for selective separation applications and provided critical comparisons based on the as-achieved excellent rebinding and permselectivity performance, which encompassed innovative GO/SiO2-loaded nanocomposite and PDA-based dual-TC-imprinted system.

Inspired by the easy intercalation of quinoxaline heterocyclic aromatic amines (HAAs) in double-stranded DNA (dsDNA), we synthesized a nucleobase-functionalized molecularly imprinted polymer (MIP) as the recognition unit of an impedimetric chemosensor for the selective determination of a 2-amino-3,7,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) HAA. HAAs are generated in meat and fish processed at high temperatures. They are considered to be potent hazardous carcinogens. The MIP film was prepared by potentiodynamic electropolymerization of a pre-polymerization complex of two adenine- and one thymine-substituted bis(2,2′-bithien-5-yl)methane functional monomer molecules with one 7,8-DiMeIQx template molecule, in the presence of the 2,4,5,2′,4′,5′-hexa(thiophene-2-yl)-3,3′-bithiophene cross-linking monomer, in solution. The as-formed MIP chemosensor allowed for the selective impedimetric determination of 7,8-DiMeIQx in the 47 to 400 μM linear dynamic concentration range with a limit of detection of 15.5 μM. The chemosensor was successfully applied for 7,8-DiMeIQx determination in the pork meat extract as a proof of concept.

Chiral resolution of binaphthylamine is often a toilful conundrum in the field of analytical chemistry and biomedicine. The work puts forward a selective, sensitive, and miniaturized analytical method based on molecularly imprinted polymers (MIPs) as adsorbent for miniaturized tip solid-phase extraction (MTSPE) in the separation of binaphthylamine enantiomer. This method combines the advantages of MIPs (high selectivity), MTSPE (low consumption), and high-performance liquid chromatography (HPLC, high sensitivity). A simple synthesis methodology of MIP (P2) was conducted through bulk polymerization with (S)-(-)-1,1'-binaphthyl-2,2'-diamine (S-DABN) as template together with methacrylic acid monomer, and ethylene glycol dimethacrylate as cross-linker in proper porogen, realizing a selective recognition and efficient enrichment for S-DABN. The method exhibited appreciable linearity (0.06-1.00 mg ml-1 ), low quantification limit (0.056 mg ml-1 ), good absolute recoveries (45.70%-69.29%), and high precision (relative standard deviations ≤ 3.54%), along with low consumption (0.50 ml sample solution and 25.0 mg adsorbent). Based on the density functional theory, computational simulation was used to make a preliminary prediction for rational design of MIPs and gave a reasonable elaboration involving the potential mechanism of templates interacting with functional monomers. The adsorption kinetics and thermodynamics were investigated to evaluate the recombination process of substrates. In addition, the selectivity of MIPs for S-DABN was obtained by MIP-MTSPE coupled with HPLC, which supports the feasibility of this convenient design process. The proposed method was employed for selective extraction of S-DABN and exhibited promising potential in the application of chiral analysis.

Using biocompatible polymer nanofibrous conduits with a controlled drug delivery have attracted much attention for peripheral nerve regeneration. This work was aimed at preparing electrospun poly ( l -lactide-co- D , l -lactide) (PLDLLA) containing multi-walled carbon nanotubes (MWCNTs) and 4-aminopyridine (4-AP)-loaded molecularly imprinted nanoparticles (MIP4-AP) as well as evaluating their performance in in vitro and in vivo assessments. After synthesis of MIP4-AP based on poly (methacrylic acid) with imprinting factor of 1.78, it was incorporated into the PLDLLA/MWCNTs nanofibers to optimize. By adjusting the process variables, the average diameter and electrical conductivity of the nanofibrous sample were 92 nm and 2870 × 10−7 S cm−1, respectively. Afterward, 4-AP release of the optimum sample showed the presence of MIP4-AP leading to initial burst release decrease and plateau level postpone up to 96 h. Moreover, the culture results of PC12 as neuroblastoma cell line on optimal PLDLLA/MWCNTs/MIP4-AP nanofibrous sample revealed the highest cell proliferation without cytotoxicity compared to neat nanofibers. Eventually, the animal model experiment exhibited that the conductive conduit based on the optimum sample was able to repair the rat's sciatic nerve after four weeks in accordance with sciatic function index and histological studies.

Iron (Fe) is an essential mineral, but iron overload can reason in multiple organ failures and cell injury. Iron overload syndromes can be widely classified as hereditary hemochromatosis. The development of iron overload is seen in hereditary hemochromatosis, a common inherited disorder that may lead to progressive organ dysfunction including cirrhosis, arthritis, hypogonadism, diabetes mellitus, and cardiomyopathy. If patients with iron overload are not treated, their life expectancy will be shortened. Nanochelators are usually utilized to remove overload iron. Many novel nanochelator have been formulated for effective methods. The ion molecular imprinting is a technique to form recognition sites in the highly cross-linked polymer using a template ion. In this research, effective ion-imprinted polymer-based nanoparticles were synthesized and evaluated for selective removal of iron(III). The iron-imprinted nanoparticles were prepared by using functional monomer N-methacryloyl-l-glutamic acid (MAGA) and comonomer 2-hydroxyethyl methacrylate by mini-emulsion polymerization techniques. The template analyte was desorbed with 0.01 M EDTA desorption agent. The iron-imprinted nanoparticles were selective for Fe(III) toward other analogs (Zn(II), Cr(III) and Al(III)). The adsorption isotherm model fitted the Langmuir isotherm with 0.995 of R2 value and the 83.33 mg/g of Qmax value for the Fe(III)-imprinted nanoparticles. The values of separation factor (RL) were found to be 0.016 for Fe(III). The maximum binding capacity for the ion-imprinted nanoparticles was found to be 77.80 mg/g dry nanoparticles, which is 8.9 times higher than the non-imprinted nanoparticles under the same conditions. Synthetic gastric fluid experiments were also performed for Fe(III) removal.

Zearalenone is a fungal contaminant that is widely present in grains. Here, a novel molecularly imprinted membrane based on SOM-ZIF-8 was developed for the rapid and highly selective identification of zearalenone in grain samples. The molecularly imprinted membrane was prepared using polyvinylidene fluoride, cyclododecyl 2,4-dihydroxybenzoate as a template and SOM-ZIF-8 as a carrier. The factors influencing the extraction of zearalenone using this membrane, including the solution pH, extraction time, elution solvent, elution time and elution volume were studied in detail. The optimized conditions were 5 mL of sample solution at pH 6, extraction time of 45 min, 4 mL of acetonitrile:methanol=9:1 as elution solvent, and elution time of 20 min. This method displayed a good linear range of 12∼120 ng·g-1 (R2 =0.998) with the limits of detection and quantification of this method are 1.7 ng·g-1 and 5.5 ng·g-1 , respectively. In addition, the membrane was used to selectively identify zearalenone in grain samples with percent recoveries ranging from 87.9% to 101.0% and relative standard deviation of less than 6.6 %. Overall, this study presents a simple and effective chromatographic pretreatment method for detecting zearalenone in food samples. This article is protected by copyright. All rights reserved.

In this study, it presents a novel surface-enhanced Raman scattering (SERS) imprinted membrane to be applied into the detection of trace-level antibiotic in aqueous samples. Graphene oxide- argentum (GO/Ag) composites are chosen as the SERS substrates to fabricate on poly(vinylidene fluoride) (PVDF) membrane surface, increasing the hydrophilia and promoting the sensitivity. The amount of GO is investigated to confirm the optimal concentration. Whereafter, in order to effectively apply into practical sample detection, the technique of molecular imprinting is also introduced to improve the selectivity of SERS membrane. The SERS imprinted membrane (AGP-MIM) is synthesized by the process of two-step precipitation polymerization and applied into the detection of enrofloxacin hydrochloride. The characteristics are adequately investigated and proved that the AGP-MIM can be applied into practical samples detection.

An improved and alternative method for the metal-free synthesis of 5,7-dimethylcyclopentenon[2,3- c]coumarin as a possible useful aflatoxin template in the production of molecular imprinting polymers with affinity toward natural aflatoxin molecules is reported. A synthesis of 5,7-dimethylcyclopentenon[2,3- c]coumarin from 3,5-dimethoxyphenol via a Pechmann condensation involved five steps and represents an alternative commercially viable approach over existing synthetic protocols in the literature. Operational simplicity, inexpensive key raw materials, short reaction times, and excellent yields are remarkable features of this approach. The aflatoxin template was provided in 55%–67% overall yield from 3,5-dimethoxyphenol with >99% purity, evaluated by high-performance liquid chromatography, 1H NMR, 13C NMR, high-resolution mass spectrometry, and liquid chromatography–mass spectrometry.

Selective photocatalysis is a very promising direction to improve the activities of photocatalysts. Combining the technique of molecular imprinting (MIP) with heterogeneous photocatalysis can be an appealing approach to achieve our aim. Herein, using the MIP technique, the monoclinic MIP-BiVO4 was successfully synthesized by the presence of rhodamine B (RhB) during the hydrothermal synthesis. The synthesized MIP-BiVO4 possessed better adsorptive and photocatalytic activities than pristine BiVO4. RhB added in the synthesis process worked as a template and served a crucial role in the formation of the MIP-BiVO4 morphology. The photoelectrochemical analysis verified the superiority of MIP-BiVO4 sample in the transfer and separation of the electron–hole pairs. Holes played the most crucial role in the degradation of the pollutants. The effective approach combining MIP technique in the synthesis of photocatalysts would provide some guidance to selective photocatalysis field for designing and synthesizing highly efficient photocatalysts.

This study determined isomeric molecules by employing molecular imprinting technology (MIP) and electrochemical impedance spectroscopy (EIS). In order to increase surface area to obtain more sensitive sensor technology, ex situ precipitation polymerization was carried out to produce microspheres. These microspheres were placed on pyrrole-modified carbon electrodes. Acrylamide, as monomer, was polymerized by cross-linker trimethylolpropane trimethacrylate (TRIM) and Azobisisobutyronitrile (AIBN) as initiator and as template molecules; chondroitin sulfate (CS) and dermatane sulfate (DS) were used. Performances of the electrodes were determined as follows, CS and DS sensor, respectively; calibration curves were calculated between 50 to 500 ng/mL and 50 to 600 ng, R-2 = 0.9942 +/- 0.0029 and R-2 = 0.9824 +/- 0.0083, LOD and LOQ were 15.19 ng/mL, 46.03 ng/mL, and 32.56 ng/mL, 102.82 ng/mL, respectively. The characterization of polymers was carried out by X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared (FTIR), and Scanning Electron Microscopy (SEM). The applicability of the optimized sensor systems to real samples was examined in urine samples and the systems were tested by LC-MS/MS method. Sensors showed a good correlation with tandem mass spectrometry.

A large number of pesticides left in the crops and water affect the environment and human health. The combination of surface-enhanced Raman scattering (SERS) technology and molecular imprinting technology (MIT) was presented to apply to the detection of target molecules in water. However, the thickness of the imprinted layer and the inhomogeneity of the shell package have a great influence on SERS detection. To overcome the above problems, a new method is proposed to control the imprinted layer within 5 nm by taking the large-scale Ag as the core, reducing the amount of reagent, increase the oscillation time of polymerization, and so on. The obtained Ag@molecular imprinted polymers (Ag@MIPs) were applied for rapid detection of carbendazim. Besides, the SERS intensity of Ag@MIPs for carbendazim was higher than that of Ag, exhibiting limit detection as low as 1 × 10−9 M. Also, Ag@MIPs is used as SERS substrate achieved high selectively and satisfactory reusability. Based on the above, the experiment results proved that the Ag@MIPs with a thin imprinted layer provided a reliable approach for carbendazim detection.

Glycoproteins play crucial roles in many biological events such as protein folding, information transmission, nerve conduction, and molecular recognition. Some glycoproteins serve as disease biomarkers in clinical settings. However, selective detection of glycoprotein often faces great challenges, owing to its low abundance in complex biological samples. In this case, develop a highly sensitive and selective approach for glycoprotein detection is urgently needed. Molecularly imprinted polymers (MIPs) have proved to be an ideal absorbent material in detection and separation science. Herein, a novel biomass activated carbon–derived imprinted polymer (BAC@PEI/PBA/MIPs) was fabricated for selective recognition of glycoprotein. The as-prepared BAC@PEI/PBA/MIPs was synthesized using waste tea derived carbon as matrix, albumin chicken egg (OVA) as template, and dopamine as functional monomer. Branched polyethyleneimine (PEI) was covalently bonded on the BAC surface to increase the number of boronic acid moieties. Benefiting from the self-polymerization of dopamine and multi-boronic acid sites, a great number of recognition sites were presented under mild conditions. The static adsorption experiment showed that the BAC@PEI/PBA/MIPs exhibited a high binding capacity of 196.2 mg/g, rapid adsorption dynamics of 40 min, excellent selectivity and satisfactory reusability for OVA. Furthermore, the practicability of BAC@PEI/PBA/MIPs was verified by isolation of OVA from egg white. The good binding performance and facile preparation process make BAC@PEI/PBA/MIPs attractive for glycoprotein recognition, indicating its potential applications in biomedical research and clinical diagnostics.

A limitation of conventional MIP in thermal and mechanical stabilities condition, improper porosity and low adsorption capacity, give a reason to introduce a sol-gel method in molecular imprinting process recently. In this study, a synthesis of new sol-gel molecularly imprinted polymer (SG-MIP) was studied for crystal violet (CV) selective recognition. The control non-molecularly imprinted polymer (SG-NIP) was also synthesized as reference. The preparation of SG-MIP was introduced by a combination of the organic and inorganic mixture. The organic solution included the methacrylic acid, trimethylolpropane trimethacrylate, and benzoyl peroxide which are monomer, crosslinker, and initiator, respectively. The inorganic solution involved the ratio of tetraethyl orthosilicate: ethanol (1:1 v/v). The functional group analysis proved the successful synthesized SG-MIP and SG-NIP. The thermal analysis indicated high thermal stability for SG-MIP and SG-NIP, respectively. The morphology and surface analyses showed the respective different structures, surface, and porosity values between SG-MIP and SG-NIP, which influence the selectivity study and adsorption behaviour of SG-MIP toward CV adsorption. The result verified that the SG-MIP (4.900 mgg-1) has higher adsorption and higher selectivity characteristics compared to SG-NIP (4.432 mgg-1). The equilibrium data of kinetic and isotherm studies for SG-MIP and SG-NIP were well-fitted to the pseudo-second order model (R2 = 0.9997 and R2 = 0.9996) and Freundlich isotherm model (R2 = 0.9500 and R2 = 0.9764), respectively. The Freundlich isotherm was supported by the Scatchard plot instead of the Langmuir isotherm model.

Two novel Ag(I) complexes containing synergistic pyridine and amidoxime ligands (Ag-DPAAO and Ag-PAAO) were first designed as complex monomers. Taking advantage of the molecular imprinting technique and solvothermal method, molecular imprinted porous cross-linked polymers (MIPCPs) were developed as a robust platform for the first time to incorporate Ag-PAAO into a polymer material as a recyclable catalyst. Advantageously, the observed pseudo first-order rate constant (kobs) of MIPCP-Ag-PAAO-20% for ethyl-parathion (EP) hydrolysis is about 1.2 × 104-fold higher than that of self-hydrolysis (30 °C, pH = 9). Furthermore, the reaction mechanism of the MIPCP-containing Ag-PAAO-catalyzed organothiophosphate was analyzed in detail using density functional theory and experimental spectra, indicating that the amidoxime can display dual roles for both the key coordination with the silver ion and nucleophilic attack to weaken the P-OAr bond in the catalytic active site.

In this study, a novel kind of imprinted polymers based on metal–organic frameworks (MOF@DES-MIPs) was prepared, using bovine hemoglobin (BHb) as template molecules and deep eutectic solvents (DES) as functional monomers for selective recognition and adsorption of BHb. MOF were used as the substrates to improve the accessibility of imprinted sites and DES as the functional monomers to produce different forces for BHb to help the formation of imprinted sites. Imprinted polymer films were taken to provide analyte selectivity. The MOF@DES-MIPs prepared were characterized and evaluated by scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectrometer. We also investigated the influences of BHb concentration and adsorption time on the performance of MOF@DES-MIPs. The maximal adsorption capacity of MOF@DES-MIPs to BHb reached 151.28 mg g−1, and the MOF@DES-MIPs showed good selectivity and fast adsorption equilibrium, which might offer a novel method for the preparation and research of molecularly imprinted polymers of biomacromolecules. In addition, MOF@DES-MIPs were successfully applied in the selective recognition of BHb from a real bovine blood sample.

Bu çalışmada, yaygın olarak kullanılan doğal bir antioksidan olan gallik asidin (GA) moleküler baskılama yöntemi kullanılarak hazırlanan polimerlerle (MIP) bitki örneklerinden seçici ayrılması gerçekleştirilmiştir. Emülsiyon polimerizasyonu ile hazırlanan polimerler çeşitli yöntemlerle karakterize edilmiştir. GA adsorpsiyonunun optimizasyon çalışmaları, pH 3,5 ortamında 25°C’de 1,2 mg GA-MIP kullanılarak 60 dk sürenin GA adsorpsiyonu için en uygun koşullar olduğunu göstermiş ve GA adsorpsiyonu adsorpsiyon kinetikleri ve izotermleri ile incelenmiştir. Çalışılan tüm derişimler için IF değerinin 1’den büyük olması GA-MIP’lerin baskılanmamış polimerlere (GA-NIP) kıyasla daha fazla GA adsorpladığını kanıtlamaktadır. Ayrıca, IF değerinin GA derişimiyle ters orantılı olarak azalması spesifik olmayan etkileşimlerden kaynaklanmaktadır. MIP’lerin seçiciliğini belirlemek amacıyla GA analogları kullanılarak yarışmalı adsorpsiyon çalışmaları yapılmış ve GA ve analoglarının miktarları yüksek performanslı sıvı kromatografisi ile analiz edilmiştir. Tüm bağıl seçicilik katsayılarının 1’den büyük olması GA-MIP’lerin baskılanmamış polimerlere kıyasla GA’yı tüm analoglarından daha fazla adsorpladığını göstermektedir. Yeşil çay, siyah çay ve karanfil örnekleri ile yapılan gerçek örnek çalışmaları sonucunda en etkin GA adsorpsiyonu ve geri alımının karanfil örnekleriyle elde edildiği belirlenmiştir. HPLC kromatogramları incelendiğinde, GA’nın etkin ve seçici olarak MIP’lerden geri alındığı belirlenmiştir.

The design and synthesis of artificial receptors based on molecular imprinting (MI) technology for the development of a new MIP-based biosensor for detection of the stress biomarker α-amylase in human saliva in point-of-care (PoC) applications is described in this work. The portable electrochemical devices for monitoring α-amylase consists of cost-effective and disposable gold screen-printed electrodes (AuSPEs). To build the electrochemical device, the template biomolecule was firstly immobilized directly over the working area of the gold chip previously activated with a self-assembled monolayer (SAM) of cysteamine (CA). Then, pyrrole (Py) monomer was selected as building block of a polymeric network prepared by CV electropolymerization. After the electropolymerization process, the enzyme was removed from the polymer film in order to build the specific recognition sites for the target enzyme. The MIP biosensor showed a very wide linear concentration range (between 3.0 × 10−4 to 0.60 mg mL−1 in buffer solution and between 3.0 × 10−4 to 3.0 × 10−2 mg mL−1 in human saliva) and low detection levels were achieved (LOD &lt, 3.0 × 10−4 mg mL−1) using square wave voltammetry (SWV) as the electroanalytical technique.

An imprinted electrospun fiber membrane was developed for the detection of volatile organic acids, which are key components of human body odor. In this study, hexanoic acid (HA) was selected as the target, polymethyl methacrylate (PMMA) was used as the substrate, and colorimetric detection of HA was achieved by a bromocresol purple (BCP) chromogenic agent. The results showed that the morphology of the fiber membrane was uniform and continuous, and it showed excellent selectivity and specificity to HA. Photographs of the color changes before and after fiber membrane adsorption were recorded by a camera and quantified by ImageJ software by the difference in gray value (ΔGray). This method is simple, intuitive, and low cost and has great potential for application in human odor analysis.

Biological recognition sites are very useful for biomedical purposes and, more specifically, for polymeric scaffolds. However, synthetic polymers are not capable of providing specific biological recognition sites. To solve this inconvenience, functionalization of biological moieties is typically performed, oftentimes via peptide binding. In this sense, the main task is capturing the biological complexity of a protein. This study proposes a possible alternative solution to this challenge. Our approach is based on the combination of molecular imprinting (MI) and electrospinning processes. We propose here an alternative MI approach with polymeric structures, instead of using cross-linkers and monomers as conventionally performed. Different PCL–protein scaffolds were produced via electrospinning before performing MI. Gelatin, collagen, and elastin were used as proteins. Results evidenced that the MI process conducted with PCL electrospun membranes was carried out with ionic interactions between the desired molecules and the recognition sites formed. In addition, it has been proved that MI was more efficient when using gelatin as a template. This approach opens a new stage in the development of recognition sites in scaffolds obtained with synthetic polymers and their application for biomedical purposes. Ministerio de Economía y Competitividad (MINECO/ FEDER, EU) CTQ2015-71164-P

An electrochemical sensor with high sensitivity and selectivity and excellent stability was developed for the determination of sofosbuvir (SOF), based on molecular imprinting strategy. The imprinted polymer was fabricated using acrylamide and methacrylic acid as monomers, 2, 2′-azobisisobutyronitrile (initiator), SOF as a template and ethylene glycol dimethacrylate (cross-linker). Fourier transform infrared spectroscopy, energy-dispersive X-ray and scanning electron microscopy were used for the characterization of the morphology and composition of the synthesized polymer. The proposed sensor was designed layer-by-layer assembled graphene oxide and imprinted polymer film on the surface of glassy carbon electrode. Cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy were utilized to investigate the electrochemical behavior of the modified sensor toward SOF. Under the optimum experimental condition, the relative current intensity of the sensor is directly proportional to the concentration of SOF in the range from 1 nM to 0.83 mM with lower detection limit of 0.013 nM. Moreover, the proposed sensor exhibited high selectivity (imprinting factor = 5.2), temporal stability (5 weeks), good reproducibility (RSD = 2.1%) and excellent sensitivity. Finally, the imprinted sensor was successfully applied for detection of SOF tracing in human blood of pre-treated patients and in sovaldi tablets with good recovery (98.5–100.7%).

A microcrystalline cellulose-based temperature sensitivity paclitaxel molecular imprinted hydrogel (MCC-TSMIHs-PTX) was successfully prepared by temperature-sensitive monomer N-isopropylacrylamide, functional monomer 4-vinylpyridine, cross-linking agent N, N'-methylenebisacrylamide and microcrystalline cellulose. They showed imprinting effective responses to the temperature changes. The results of adsorption kinetics, adsorption equilibrium, thermodynamics, selectivity and reusability showed the successful formation of a grafting thermosensitivity hydrogel with higher adsorption capacity and specific recognition. When the temperature reached 308 K, imprinting effect of hydrogel cavities would be most effective and conducive to capture template molecules. When the temperature reached 288 K, the lowest imprinting effect would facilitate the desorption of PTX. Finally, the MCC-TSMIHs-PTX was applied to enrich the paclitaxel in Taxus × media extracts samples, the relative contents of PTX in the samples were increased greatly from 7.23% to 78.32%, indicating the MCC-TSMIHs-PTX was a stable adsorption capacity for efficient separation and enrichment of PTX in Taxus × media extracts.

Lactase, which can cause lactose intolerance in its deficiency, is a vital enzyme concerning digestion. To overcome lactose intolerance for patients with digestion problem depending of this kind of issue, lactose in food should be removed. In this study, lactose imprinted poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-aspartic acid), poly(HEMA-MAsp), cryogels were synthesized to reduce the amount of lactose content of milk samples. Occurrence of desired bounds, structural integrity, and surface characteristics were analyzed via Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscope (SEM), micro computed tomography (CT), and confocal microscope methods. Water retention characteristic were tested in solution with different electrolytic nature. Adsorption parameters were optimized in an aqueous medium. The adsorption performance of imprinted cryogels was studied in milk samples obtained from cow, sheep, goat, buffalo, and from human volunteers at different intervals after birth. Amount of lactose adsorbed in aqueous media and milk sample from humans were 322 (56.7%) and 179.5 (5.94%) mg lactose/g polymer, respectively. Selectivity studies revealed an approximately 8-fold increase in adsorption rate of molecularly imprinted cryogels as compared to that of nonimprinted cryogels. In addition, competitive adsorption was conducted using lactose-imprinted cryogels in aqueous media containing lactose, glucose, and galactose molecules resulting in adsorption rates of 220.56, 57.87, and 61.65 mg biomolecule/g polymer, respectively. Hitit University Scientific Research Projects Coordination UnitHitit University [ALACA19001.17.001] This study was supported by Hitit University Scientific Research Projects Coordination Unit with the project ALACA19001.17.001. WOS:000681143500006 2-s2.0-85108100835

The scope of this project was to synthesis a ZnO-Cr2O3 for selective imatinib removal. Molecular imprinting was used to prepare polymerisation using ZnO-Cr2O3 with tetraethyl orthosilicate and 3-am...

This research is focused on the experiment of molecular imprinting polymers by supercritical solvent technology as friendly-environmental process. Methyl methacrylate (MMA) monomer, methacrylic acid (MAA) monomer, VA (vanillic acid) with template and EGDMA (ethylene glycol dimethacrylate) with cross-linking agent were used for molecular imprinting polymers composition. The template has been eliminated by the Soxhlet extraction method, and the rate of elimination is ca. 95–98 %. The adsorption capacities of the synthesized molecular imprinting polymers were estimated using the kinetics and isotherms of restraint, Scatchard investigation, affinity distributions, the materials adsorption with template-like structure, α (selectivity parameter), and HPLC (high performance liquid chromatography) analysis. The evaluation result shows that the manufactured molecular imprinting polymers have highly selectivity and separation ability. It was also confirmed that there was a difference between the adsorption amounts with EGDMA contents. In this study, prepared molecular imprinting polymers had an advantage in adsorption selectivity where VA and its structural analog materials are present. These results show that the molecular imprinting polymers selectivity was increased using control the cross-linking agent.

Depletion of human serum albumin (HSA), the most abundant protein in human plasma, from serum/plasma is a prerequisite before their proteomic analysis. Molecularly imprinted polymers (MIPs) using HSA as a template have been designed for this purpose, but suffer from a low sorption capacity and low selectivity. Here, a new HSA-imprinted polymer was synthesized using N-isopropylacrylamide (NIPAM) as the main monomer; acrylamide (AAm), methacrylic acid (MAA), and dimethylaminoethyl methacrylate (DMAEMA) as functional monomers; and oligoglutamic acid-based peptide crosslinker (PC) as a crosslinker at pH 5.5. When pH is adjusted to 7.4, the peptide chains in the polymer change from a helical conformation to an extended coil conformation, and the polymer swells. Consequently, the template protein is removed completely. When pH is adjusted back to 5.5, the peptide chains fold back precisely to the helical conformation. Both the size and shape of the imprint cavities are restored. Therefore, the polymer rebinds the template protein selectively. Highest imprinting factor (IF) was observed at pH 5.5 at which the polymer was synthesized. The IF increases with the increasing number of glutamic acid residues in the PCs because of their increased degree of helicity at pH 5.5. No improvement in imprinting effect was observed when using a peptide crosslinker containing both L- and D-glutamic acid residues and hence incapable of folding into α-helix, further confirming the key role of the pH-induced helix-coil transition of the peptide chains. The MIP synthesized here presents a much higher affinity to HSA than the nontemplate proteins. It could be used repeatedly without evident decrease in sorption capacity. Because of the mild eluting conditions, the secondary structure of the extracted HSA protein remains unchanged. Finally, the MIP was used to deplete HSA from human serum. Because of its high sorption capacity and high selectivity, HSA was depleted completely and selectively. STATEMENT OF SIGNIFICANCE: A new molecularly imprinted polymer (MIP) using human serum albumin (HSA) as a template was synthesized using N-isopropylacrylamide (NIPAM) as the main monomer; acrylamide (AAm), methacrylic acid (MAA), and dimethylaminoethyl methacrylate (DMAEMA) as functional monomers; and oligoglutamic acid-based peptide crosslinker as a crosslinker. Because of the reversible and precise pH-induced helix-coil transition of the peptide chains, the template protein was removed facilely and completely under mild conditions. Simultaneously, a significant improvement in imprinting efficiency was obtained. The sorption capacity was as high as 648.05 mg/g and the imprinting factor was 7.9. Because of its high selectivity and high binding capacity, the MIP synthesized here is highly promising for the depletion of HSA, the most abundant protein in serum, which is a prerequisite for its proteomic analysis. For the first time, complete and selective depletion of HSA from human serum was achieved using a protein-imprinted polymer.

The ion/molecular imprinting technique is an efficient method for developing materials with high adsorption selectivity. However, it is still difficult to obtain an imprinted adsorbent with desirably high selectivity when the preparation processes are not well designed and optimized. In this present work, a chitosan-based ion-imprinted adsorbent was optimally prepared through Box-Behnken experimental design to achieve desirably high selectivity for Pd anions (PdCl42-) from aqueous solutions with high acidity. The dosage of epichlorohydrin (ECH) used in the first and second steps of cross-linking as well as the pH of the imprinting reaction medium is likely one of the key factors affecting the selectivity of the synthesized ion-imprinted chitosan adsorbent, which were selected as factors in a three-level factorial Box-Behnken design. As a result, the effects of these three factors on Pd(II) selectivity were able to be described by using a second-order polynomial model with a high regression coefficient (R2; 0.996). The obtained optimal conditions via the response surface methodology were 0.10% (v/v) of first cross-linking ECH, an imprinting pH of 1.0, and 1.00% of second cross-linking ECH. Competitive adsorption was performed to investigate the selectivities of the ion-imprinted chitosan adsorbents prepared under the optimal conditions. The selectivity coefficient of Pd(II) versus Pt(IV) (βPd/Pt) of the Pd(II)-imprinted adsorbent was 115.83, much greater than that of the chitosan adsorbent without imprinting and various reported selective adsorbents. Therefore, the Box-Behnken design can be a useful method for optimizing the synthesis of ion-imprinted adsorbents with desirably high adsorptive selectivity for precious metals.

Nowadays, the employing of molecular imprinting technique in the analysis and separation of proteins from complex biological samples has been widely favored by researchers. To enrich the types of surface protein imprinted materials and expand the application fields of graphene materials, novel surface molecular imprinted polymers (MIPs) based on magnetic graphene microspheres Fe3O4@rGO@MIPs are first synthesized in this paper. Fe3O4@rGO@MIPs are prepared by oxidative self-polymerization of dopamine on the surface of magnetic graphene (Fe3O4@rGO) composite microspheres. Bovine serum albumin (BSA) is selected as protein template. Fe3O4@rGO microspheres with wrinkled flower-like structure are obtained by compounding Fe3O4 and graphene oxide in an appropriate ratio via the method of high-temperature reduction self-assembly. The microspheres exhibit promising dispersibility, high external surface area, rich pore structure, and sufficient magnetic properties. These advantages not only prevent the agglomeration of imprinted microspheres in the aqueous phase, which is conducive to contact and static adsorption, but also increase the amount of protein imprinting. Additionally, sufficient magnetic properties ensure fast and effective separation of the adsorbents. While the adsorption capacity is increased, the separation procedure becomes simple. The binding capacity of Fe3O4@rGO@MIPs for BSA can reach 317.58 mg/g within 60 min, and the imprinting factor (IF) is 4.24. More importantly, Fe3O4@rGO@MIPs can specifically recognize the target BSA from the mixed proteins and the actual sample. There is no significant decrease in the adsorption amount, IF, and magnetic properties after eight runs. It is promising to be used in the separation of proteins from the actual biological samples.

Site-isolation of catalysts can enable incompatible catalysts such as acid and base to be used in one pot for enhanced efficiency and other benefits. Although many synthetic platforms have been reported for this purpose, they generally do not possess the exquisite selectivity of site-isolated enzymes in nature. Here we report water-soluble protein-sized nanoparticles with site-isolated acids in the core and amines on the surface. The catalysts were made through molecular imprinting of cross-linked micelles, followed by facile one-step photoaffinity labeling of the imprinted binding site. With a tunable, substrate-specific active site, the bifunctional artificial enzyme catalyzed highly selective tandem cross aldol reaction between acetone and mixtures of isomeric aryl acetals. It could also transform a less reactive substrate over a more reactive one.

A hybrid bifunctional core–shell nanostructure was synthesized for the first time via surface-initiated atom transfer radical polymerization (SI-ATRP) using myoglobin as a biocatalyst (ATRPase) in an aqueous solution. N-Isopropyl acrylamide (NIPA) and N-(3-aminopropyl)methacrylamide (APMA) were applied to graft flexible polymer brushes onto initiator-functionalized silica nanoparticles. Two different approaches were implemented to form the core–shell nanocomposite: (a) random copolymerization, Si@p(NIPA-co-APMA) and (b) sequential block copolymerization, Si@pNIPA-b-pAPMA. These nanocomposites can be used as versatile intermediates, thereby leading to different types of materials for targeted applications. In this work, a phenylboronic acid ligand was immobilized on the side chain of the grafted brushes during a series of postmodification reactions to create a boronate affinity adsorbent. The ability to selectively bind glycoproteins (ovalbumin and glycated hemoglobin) via boronic acid was assessed at two different temperatures (20 and 40 °C), where Si@pNIPA-b-APMABA (163 mg OVA/g of particle) displayed an approximately 1.5-fold higher capacity than Si@p(NIPA-co-APMA)BA (107 mg OVA/g of particle). In addition to selective binding to glycoproteins, the nanocomposites exhibited selective binding for myoglobin due to the molecular imprinting effect during the postmodification process, that is, 72 and 111 mg Mb/g for Si@p(NIPA-co-APMA)BA and Si@pNIPA-b-pAPMABA, respectively.

The pesticide residues have become one of the issues in the fields of environmental health and food safety. Herein, an effective method was successfully developed to rapidly determine imidacloprid in environmental water samples based on magnetic molecular imprinted polymers (MMIP) coupled with high-performance liquid chromatography. MMIP were creatively synthesized in one-pot synthesis step via the nucleation process of Fe3O4 magnetic nanoparticles and the polymerization process of molecular imprinted polymers simultaneously, using imidacloprid as template and dopamine as functional monomer. The parameters effected on the extraction efficiency, including pH value and the amount of the adsorbent, have been optimized. Under the optimal conditions, MMIP was used to extract imidacloprid in water samples with excellent recovery (88–97.3%) and precision (1.2–3.3%). Therefore, magnetic nanoparticles-based dispersion solid-phase extraction could be a good candidate for highly efficient extraction of imidacloprid without complicated operations.

Nanoscale molecularly imprinted polymers (nanoMIPs) are powerful molecular recognition tools with broad applications in the diagnosis, prognosis, and treatment of complex diseases. In this work, fully atomistic molecular dynamics (MD) simulations are used to assist the design of nanoMIPs with recognition capacity toward l-fucose and d-mannose as prototype disease biomarkers. MD simulations were conducted on prepolymerization mixtures containing different molar ratios of the monomers N-isopropylacrylamide (NIPAM), methacrylamide (MAM), and (4-acrylamidophenyl)(amino)methaniminium acetate (AB) and fixed molar ratios of the cross-linker ethylene glycol dimethacrylate (EGDMA) in explicit acetonitrile as the porogenic solvent. Prepolymerization mixtures containing ternary mixtures of NIPAM (50%), MAM (25%), and AB (25%) exhibit the best imprinting potential for both l-fucose and d-mannose, as they maximize (i) the stability of template-monomer plus template-cross-linker interactions, (ii) the number of functional monomers plus cross-linkers organized around the template, and (iii) the number of hydrogen bonds participating in template recognition. The studied prepolymerization mixtures exhibit an overall increased recognition capacity toward d-mannose over l-fucose, which is attributed to the higher hydrogen-bonding capacity of the former template. Our results are valuable to guide the synthesis of efficient nanoMIPs for sugar recognition and provide a computational framework extensible to any other template, monomer, or cross-linker combination, thus constituting a promising strategy for the rational design of molecularly imprinted materials.

The boronate affinity-based oriented and double-shelled surface molecularly imprinted polymers on 96-well microplates (BDMIPs) were designed and applied to high-specific and high-throughput pharmacokinetic (PK) study of rutin and its metabolites from rat plasma without concentration and redissolution. It integrated the advantages of covalent effects-based boronate affinity, noncovalent effects of ethylene imine polymer (PEI) dendrimer, multiple cavities-based double-shelled layers, and multiparallel wells-based 96-well microplates. Furthermore, ultrahigh-performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) was used to accurately quantify targets. It showed lower limits of detection (LODs) up to 100-fold than the conventional method. And PKs of rutin and trace isoquercetin (IQC) were first reported at the same time. The platform can provide a fast, simple, low-cost, high-selective, high-effective, and high-throughput methodological reference for analysis of large-scale samples in the fields of agriculture and food.

Molecularly-imprinted polyampholyte (MIP) hydrogels based on nonionic monomer – acrylamide (AAm), anionic monomer – sodium salt of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and cationic monomer – (3-acrylamidopropyl)trimethyl ammonium chloride (APTAC) were obtained by immobilization of bovine serum albumin (BSA) and lysozyme in situ polymerization conditions. It was found that the best amphoteric hydrogel for sorption of BSA is APTAC-75H while for sorption of lysozyme is AMPS-75H. The sorption capacity of APTAC-75H and AMPS-75H with respect to BSA and lysozyme is 305.7 and 64.1-74.8 mg per 1 g of hydrogel respectively. Desorption of BSA and lysozyme from MIP template performed by aqueous solution of 1M NaCl is equal to 82-88%. Separation of BSA and lysozyme from their mixture was performed on MIP templates. The results of adsorption-desorption cycles of BSA on adjusted to BSA polyampholyte hydrogel APTAC-75H and of lysozyme on adjusted to lysozyme polyampholyte hydrogel AMPS-75H show that the mixture of BSA and lysozyme can be selectively separated with the help of MIP hydrogels.

Molecular imprinting-based solid-phase extraction has been in the spotlight to improve recognition selectivity and detection sensitivity of andrographolides. The synthesis of molecularly imprinted polymers on micro centrifuge tube filters for the extraction and the determination of andrographolides were investigated. Molecularly imprinted polymers were synthesized using the photo-polymerization method for the preconcentration of andrographolides (AD) template molecule using 2,2-dimethoxy-2-phenylacetophenone as initiators, the mixture of 1-dodecanol and toluene solvent, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate as functional monomers and cross-linked, respectively. The resultant AD molecularly imprinted polymers (AD-MIPs) were characterized using the Fourier-transform infrared spectrum and scanning electron microscopy. The maximum adsorption of AD-MIPs toward the andrographolides was found to be 85%, and could reach binding equilibrium within 60 min. The sample solution was separated by AD-MIP using solid-phase extraction (SPE). Subsequently, the sample solution was analyzed by the high-performance liquid chromatography (HPLC) method. The AD-MIP could be successfully applied to specifically separate and determine the andrographolides from pharmaceutical products and biological fluid samples with relatively high recoveries (102.01–108.61%). The present method is simple, selective, accurate, and provides a promising alternative to traditional SPE sorbents for the extraction and determination of andrographolides in real samples and biological fluid samples.

Purpose In this study, a novel glutathione (GSH) surface molecular imprinting polymer (SMIP) was successfully prepared by using macroporous adsorption resins (MAR) as substrate, which could separate and purify GSH efficiently. Design/methodology/approach SMIP was synthesized by chloromethylated modified MAR (LX1180-Cl) as the substrate, N, N’-methylenebisacrylamide (NMBA) as a crosslinker, GSH as a template, acrylamide (AM) and N-vinylpyrrolidone (NVP) as functional monomers. The morphology and structure of the polymer were characterized by scanning electron microscope and Fourier transforms infrared spectroscopy. Findings The maximum adsorption capacity toward GSH was 39.0 mg/g and the separation decree had relation to L-cysteine (L-cys) was 4.2. The optimal operation conditions were studied in detail and the got as follows: the molar ratios of NMBA, AM, GSH and NVP, were 7.0, 0.8 and 0.5. The optimal time and temperature were 14 h and 40°C, respectively. The Langmuir and pseudo-first-order model were fitting these adsorption characteristics well. Practical implications GSH has a diversity of medicinal and bioactive functions, so the purpose of this study representing a method in separate and purify technology of GSH, which provided a way for the development of medicine. Originality/value This contribution provided a novel way to separate GSH from L-cys. Under the optimal conditions, the maximum adsorption capacity toward GSH was 39.0 mg/g and the separation decree had relation to L-cys was 4.2.

Monitoring the residual toxicant concentrations in foods is the key step for minimizing potential hazards. The huge interest about food contamination and exposure to endocrine disruptors such as bisphenol A has emerged the development of sensitive analytical methodologies to guarantee the safety and quality of foods. In this work, a green molecularly imprinted solid-phase extraction protocol coupled with high-performance liquid chromatography with UV detection was optimized following the principles of green analytical chemistry. An imprinted sol-gel silica-based hybrid inorganic-organic polymeric sorbent was used to monitor the leaching of bisphenol A from different packaging materials (glass vessels, cans, and polypropylene containers) in walnuts stored within a period of 6 months at 25 and 4°C. Extraction parameters including loading time (5-20 min), solvent type (acetonitrile, ethanol, methanol, acetone, acetonitrile:methanol, 50:50, v/v), and elution flow rate (0.2-1 mL/min) were optimized with one-factor-at-a-time method. The selected extraction optimum parameters incorporated elution with acetonitrile at 0.2 mL/min flow rate, for 10 min sample holding time. The imprinting factor was equal to 4.55 ± 0.26 (n = 3). The optimized method presented high recovery (94.3 ± 4.2%, n = 3), good linearity (>0.999), intra-assay repeatability (90.2-95.6%, n = 3), and interassay precision (86.7-93.1%, n = 3).

Lime juice as the most commonly used natural source production can be characterized using determination of flavonoids contents such as hesperidin. So, development of analyzing methods for checking the quality and healthiness of lime juices is necessary. In this study, we aimed to set up a selective solid phase extraction method using dummy molecularly imprinting approach for extraction and separation of hesperidin in lime juice to check the quality of commercial lime juice products of Mashhad city market. The imprinted polymers were synthesized by hesperitin as dummy template due to the hesperitin solubility in the wide range of porogenic solvents. The specificity extent of synthesized polymers toward hesperidin was tested and optimum one was used as adsorbent in solid-phase extraction cartridge. The dummy molecularly imprinted polymer with high adsorption capacity for hesperidin (dissociation constant 0.12 μM) was successfully used for extraction and clean-up of hesperidin in the lime juice matrix prior to analysis by high-performance liquid chromatography. The analysis of hesperidin was done in the range of 0.312-50 μg/mL with detection limit of 0.05 μg/mL. This technique was successfully set up to remove the interfering compounds for analysis of hesperidin in commercial lime juice products.

In this article, we report on the development of a catheter-based, biomimetic sensor as a step toward a minimally invasive diagnostic instrument in the context of functional bowel disorders. Histamine is a key mediator in allergic and inflammatory processes in the small intestines; however, it is a challenge to determine histamine levels at the duodenal mucosa, and classical bioreceptors are unsuitable for use in the digestive medium of bowel fluid. Therefore, we have developed molecularly imprinted polypyrrole coatings for impedimetric sensing electrodes, which enable the quantification of histamine in nondiluted, human bowel fluid in a broad concentration range from 25 nM to 1 mu M. The electrodes show negligible cross-sensitivity to histidine as a competitor molecule and, for comparison, we also evaluated the response of nonimprinted and taurine-imprinted polypyrrole to histamine. Furthermore, using equivalent-circuit modeling, we found that the molecular recognition of histamine by polypyrrole primarily increases the resistive component of the electrode-liquid interface while capacitive effects are negligible. The sensor, integrated into a catheter, measures differentially to correct for nonspecific adsorption effects in the complex matrix of bowel fluids, and a single triggering frequency is sufficient to determine histamine concentrations. Together, these features are beneficial for real-time diagnostic tests.

Here, we report on an electrochemical biosensor based on core-shell structure of gold nano/micro-islands (NMIs) and electropolymerized imprinted ortho-phenylenediamine (o-PD) for detection of heart-fatty acid binding protein (H-FABP). The shape and distribution of NMIs (the core) were tuned by controlled electrodeposition of gold on a thin layer of electrochemically reduced graphene oxide (ERGO). NMIs feature a large active surface area to achieve a low detection limit (2.29 fg mL-1, a sensitivity of 1.34 × 1013 μA mM-1) and a wide linear range of detection (1 fg mL-1 to 100 ng mL-1) in PBS. Facile template H-FABP removal from the layer (the shell) in less than 1 min, high specificity against interference from myoglobin and troponin T, great stability at ambient temperature, and rapidity in detection of H-FABP (approximately 30 s) are other advantages of this biomimetic biosensor. The electrochemical measurements in human serum, human plasma, and bovine serum showed acceptable recovery (between 91.1 ± 1.7 and 112.9 ± 2.1%) in comparison with the ELISA method. Moreover, the performance of the biosensor in clinical serum showed lower detection time and limit of detection against lateral flow assay (LFA) rapid test kits, as a reference method. Ultimately, the proposed biosensor based on the core-shell structure of gold NMIs and MIP opens interesting avenues in the detection of proteins with low cost, high sensitivity and significantstability for clinical applications.

Surface-enhanced Raman scattering (SERS) is a promising technique for rapid detection of pesticide residues. However, conventional SERS substrates require extraction processes which are time consuming and they also lack selectivity, stability and reproducibility. Herein, we present a multifunctional stable zero-valent iron based core-shell substrate. It combines magnetic separation, selective adsorption by molecular imprinting technique and sensitive detection of carbaryl by SERS. The core-shell substrate was successfully prepared by immobilizing silver on the surface of zero-valent iron microspheres. Subsequent molecular imprinting on the bimetallic magnetic silver microspheres ensured selective removal and detection. The substrate exhibited magnetization saturation of 8.89 emu/g providing efficient analyte separation. It showed high sensitivity and selectivity toward carbaryl detection to nanomolar concentration level. Linear regression models for peaks at Raman shift 1599 cm

Fruits and vegetable waste (FVW) have been reported to have micronutrient and bioactive compound like polyphenol albeit in very small quantity (μg g−1). The challenge of selective separation and recovery of one of the polyphenols from dilute solution is addressed in the present work using molecular imprinting technique, which uses molecularly imprinted polymers (MIPs). This study focuses on the extraction of a high value bioactive compound [P-Hydroxybenzoic acid (PHBA)] which is present in FVW. Chitosan-based PHBA imprinted polymer was synthesized using PHBA as template and TEOS as cross-linker to achieve the above goal. MIP was characterized using SEM, EDAX and FTIR. Batch adsorption studies were conducted to optimize the adsorbent dose, initial concentration, and contact time. Two-parameter isotherm models namely Langmuir, Freundlich, Temkin and Dubinin–Radushkevich and three-parameter isotherm model Sips was used to analyze the experimental data. The equilibrium data fitted best into Langmuir isotherms model with capacity of 74.56 mg g −1 and followed pseudo-second-order kinetic model. The reusability confirmed that MIP retained its adsorption capacity up to 6 cycles.

In order to obtain high derivatization efficiency, the overuse of derivative agent 2,4-dinitrophenylhydrazine (2,4-DNPH) is necessary for carbonyl detection. But, the 2,4-DNPH residue will cause background interferences and limit the pre-concentration factor of the target analytes. In order to overcome the bottleneck problems, the magnetic molecularly imprinted polymer based solid-phase extraction (MMIPs-SPE) method was developed with 2,4-dinitroaniline (2,4-DNAN) as the dummy template. The characteristics and selectivity of the MMIPs were investigated. Under the optimized conditions, the enrichment of carbonyls-DNPH derivatives with simultaneous removal of the surplus 2,4-DNPH was achieved. By coupling with capillary electrophoresis (CE), a satisfactory analytical performance was obtained with the detection limit ranging from 1.2 to 8.7 μg L−1 for 8 carbonyls. The MMIPs-SPE-CE method was applied successfully for the carbonyl assessment in stream water, tap water and bottled water. In addition, the migration of carbonyls in bottled drinking water was investigated under UV irradiation and heating.

Made available in DSpace on 2021-06-25T10:45:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-25 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Lactose (LAC) is a disaccharide - major sugar, present in milk and dairy products. LAC content is an important indicator of milk quality and abnormalities in food industries, as well as in human and animal health. The present study reports the development of an innovative imprinted voltammetric sensor for sensitive detection of LAC. The sensor was constructed using electropolymerized pyrrole (Py) molecularly imprinted polymer (MIP) on graphite paper electrode (PE). The MIP film was constructed through the electrosynthesis of polypyrrole (PPy) in the presence of LAC (template molecule) on PE (PPy/PE). To optimize the detection conditions, several factors affecting the PPy/PE sensor performance were assessed by multivariate methods (Plackett–Burman design and central composite design). Under optimized conditions, the proposed analytical method was applied for LAC detection in whole and LAC-free milks, where it demonstrated high sensitivity and selectivity, with two dynamic linear ranges of concentration (1.0–10 nmol L−1 and 25–125 nmol L−1) and a detection limit of 0.88 nmol L−1. The MIP sensor showed selective molecular recognition for LAC in the presence of structurally related molecules. The proposed PPy/PE sensor exhibited good stability, as well as excellent reproducibility and repeatability. Based on the results obtained, the PPy/PE is found to be highly promising for sensitive detection of LAC. Analytical Chemistry Department Institute of Chemistry São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State Institute of Exact and Natural Sciences of Pontal Federal University of Uberlandia, 1600 20 St., Ituiutaba, Minas Gerais State Bioenergy Research Institute (IPBEN) São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State Analytical Chemistry Department Institute of Chemistry São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State Bioenergy Research Institute (IPBEN) São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State FAPESP: 2017/25329–6 FAPESP: 2018/12131–6 FAPESP: 2019/13818–8 CNPq: 408783/2018–4 CNPq: 443315/2014–0 CNPq: 447668/2014–5 CAPES: 88887.368610/2019–00 FAPEMIG: APQ-02078-15 FAPEMIG: APQ-02905-15

A molecularly imprinted polymer (MIP) sensor was offered for nevirapine (NVP) analysis based on the electropolymerization of pyrrole (Py) on electrochemically reduced graphene oxide (ErGO) immobilized on a glassy carbon electrode (GCE). Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and atomic force microscope (AFM) were applied to characterize the proposed sensor (MIP/ErGO/GCE). The electrochemical operation of this sensor for NVP analysis was tested using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) methods in an alkaline medium. The prepared MIP/ErGO/GCE exhibited better analytical performance than other modified electrodes toward NVP detection. The offered sensor depicted a linearity range between 0.005 µM and 400 µM with a limit of detection (LOD) of 2 nM under optimal conditions. Notably, the offered sensor illustrated excellent selectivity, good reproducibility, acceptable repeatability, and reliable long-term performance. These experiments depicted the constructed sensor as a favorable and good sensing element towards NVP monitoring in pharmaceutical and serum samples.

The imprinted polymers were prepared to absorb dichlorophen (DCP) by using mesoporous silica with ordered pores and high specific surface area. Both scanning electron microscopy and transmission electron microscopy results suggested that the mesoporous silica nanosphere pores had a periodic distribution. The imprinted layer of polymers was thin and uniform. The adsorption experiments showed that the adsorption of imprinted polymers was obviously improved due to the presence of mesoporous structure. The maximum adsorption capacity of MSNs@MIPs at 318 K was 91.1 mg/g, and the adsorption process rapidly reached the equilibrium within 40 min. The adsorption isotherm was well fitted by the Freundlich isotherm model, indicating that multimolecular layer adsorption mechanism governs the adsorption of DCP by the polymers. The adsorption of MSNs@MIPs complied with pseudo-second-order kinetic model. Both selective and regenerative experiments demonstrated that MSNs@MIPs can be successfully applied for selective adsorption of DCP.

Rapid, selective detection of biological analytes is necessary for early diagnosis, but is often complicated by the analytes being bound to proteins and the lack of fast and reliable systems available for their direct assessment. Here, a cheap, easily-assembled molecularly imprinted silica/graphene oxide hybrid is developed, which can selectively detect toxins linked to early-stage chronic kidney disease, down to femtomolar concentrations within 5 minutes. The hybrid material is capable of simultaneously and separately measuring free and bound analytes using with an ultra-low limit of detection in the femtomolar range, and uses processes intrinsically adaptable to any charged molecular analyte.

In this work, nitrogen-doped graphene oxide quantum dots (N-GOQDs) were embedded into Mo2C to prepare a nanocomposite with great electrical conductivity and a large specific surface area. We manufactured an innovative electrochemical sensor based on N-GOQDs–Mo2C and a molecularly imprinted polymer (MIP) for the highly sensitive detection of indometacin (IDMC). The MIP was synthesized by electropolymerization using acrylamide as the functional monomer and IDMC as the template molecule. N-GOQDs–Mo2C was organized by an elementary hydrothermal approach and characterized by SEM, TEM, XRD and FT-IR. In the first-rank experimental conditions, the MIP electrochemical sensor shows a wide linear range from 10−15 M to 10−5 M for IDMC detection and the detection limit is as low as 9.508 × 10−16 M. Additionally, the manufactured sensor shows great selectivity for indometacin, excellent repeatability and stableness. The sensor can be applied to the detection of indometacin in tablets and water samples with fulfilling consequence.