Search

[Display omitted] The development of soft hydrogel actuators with outstanding mechanical properties, fast actuation speed, and available quantification of self-sensing actuation remains a challenging endeavor. In this work, dopamine-decorated polypyrrole nanofibers (DAPPy) were introduced into the polyethylene glycol diacrylate (PEGDA)-crosslinked poly(N-isopropyl acrylamide) network to generate a stretchable, NIR-responsive, and strain sensitive DAPPy/PNIPAM hydrogel layer. Besides, this active layer was combined with the passive ligninsulfonate sodium/polyacrylamide (LS/PAAM) to give DAPPy/PNIPAM//LS/PAAM bilayer hydrogel actuator, which exhibits ultrafast thermo-responsive actuation (19°/s) and underwater grasping and lifting performance. Moreover, the DAPPy/PNIPAM layer has excellent electrical conductivity (0.29 S/m) and thermal conversion ability (10.8 °C/min), which enable such a conductive hydrogel to act as a highly sensitive strain and temperature sensor with real-time resistance change in response to tensile strain (gauge factor up to 3.4), applied pressure, temperature, and remote NIR light irradiation. More importantly, the bilayer hydrogel actuator can integrate both actuation and self-sensing functions through the bending angle-surface temperature-relative resistance change relationship of the photothermal process. With excellent mechanical actuation and self-sensing ability, the resulting bilayer hydrogel showed a promising application potential as soft biomimetic actuating materials and soft intelligent actuators. [ABSTRACT FROM AUTHOR]

A reliable nanotechnological sensing strategy, based on an S,N-co-doped graphene quantum dot (GQD) platform, has been developed to distinctly detect two key variants of vitamin D3, specifically the free (VD3) and the nanoencapsulated form (VD3Ms). For this purpose, food-grade vitamin D3 micelles were self-assembled using a low-energy procedure (droplet size: 49.6 nm, polydispersity index: 0.34, ζ-potential: −33 mV, encapsulation efficiency: 90 %) with an innovative surfactant mixture (Tween 60 and quillaja saponin). Herein, four fluorescent nanoprobes were also synthesized and thoroughly characterized: S,N-co-doped GQDs, α-cyclodextrin-GQDs, β-cyclodextrin-GQDs, and γ-cyclodextrin-GQDs. The goal was to achieve a selective dual sensing strategy for free VD3 and VD3Ms by exploiting their distinctive quenching behaviors. Thus, the four nanosensors allowed the individual sensing of both targets to be performed (except α-CD-GQD for VD3Ms), but S,N-GQDs were finally selected due to selectivity and sensitivity (quantum yield, QY= 0.76) criteria. This choice led to a photoinduced electron transfer (PET) mechanism associated with static quenching, where differentiation was evidenced through a displayed 13-nm hypsochromic (blue) shift when interacting with VD3Ms. The reliability of this dual approach was demonstrated through an extensive evaluation of analytical performance characteristics. The feasibility and accuracy were proven in commercial food preparations and nutritional supplements containing declared nanoencapsulated and raw VD3, whose results were validated by a paired Student's t-test comparison with a UV-Vis method. To the best of our knowledge, this represents the first non-destructive analytical approach addressing the groundbreaking foodomic trend to distinctly detect different bioactive forms of vitamin D3, while also preserving their native nanostructures as a chemical challenge, thus providing reliable information about their final stability and bioavailability. [ABSTRACT FROM AUTHOR]

Real-time tracking of neurotransmitter levels in vivo has been technically challenging due to the low spatiotemporal resolution of current methods. Since the imbalance of cortical excitation/inhibition (E:I) ratios are associated with a variety of neurological disorders, accurate monitoring of excitatory and inhibitory neurotransmitter levels is crucial for investigating the underlying neural mechanisms of these conditions. Specifically, levels of the excitatory neurotransmitter L-glutamate, and the inhibitory neurotransmitter GABA, are assumed to play critical roles in the E:I balance. Therefore, in this work, a flexible electrochemical microsensor is developed for real-time simultaneous detection of L-glutamate and GABA. The flexible polyimide substrate was used for easier handling during implantation and measurement, along with less brain damage. Further, by electrochemically depositing Pt-black nanostructures on the sensor's surface, the active surface area was enhanced for higher sensitivity. This dual neurotransmitter sensor probe was validated under various settings for its performance, including in vitro, ex vivo tests with glutamatergic neuronal cells and in vivo test with anesthetized rats. Additionally, the sensor's performance has been further investigated in terms of longevity and biocompatibility. Overall, our dual L-glutamate:GABA sensor microprobe has its unique features to enable accurate, real-time, and long-term monitoring of the E:I balance in vivo. Thus, this new tool should aid investigations of neural mechanisms of normal brain function and various neurological disorders.

High levels of unconjugated bilirubin (UB) in serum lead to asymptomatic and neonatal jaundice and brain dysfunctions. Herein, we have reported the detection of UB at as low as 1 μM in an aqueous alkaline medium using a Zn(II) complex. The specificity of the complex has been validated by the HPLC in the concentration window 6–90 μM, which is rare. The sensory response of the probe at physiological pH against nitro explosives developed it as an instant‐acting fluorosensor for picric acid (PA) and 2,4‐dinitrophenol (2,4‐DNP). Spectroscopic titration provided a binding constant of 4×105 M−1 with PA. The naked eye detection was found to be 15 μM. The solid‐state photoluminescent nature of the complex enabled it for PA sensing in the solid phase. Interestingly, the probe remained fluorescent in various volatile and non‐volatile organic solvents. As a result, it can also detect PA and 2,4‐DNP in a wide range of common organic media. NMR studies revealed the coordination of PA, 2,4‐DNP, and UB to the Zn(II) center of the probe, which is responsible for the observed quenching of the probe with the analytes. [ABSTRACT FROM AUTHOR]

Motivated by artificial intelligence, we present a novel electronic skin (e-skin) system capable of dual-sensing pressure and temperature signals. Our approach utilizes laser-induced graphene and polydimethylsiloxane, offering a simple yet efficient method for e-skin preparation. Experimental results reveal exceptional performance with good pressure sensitivity (0.037 kPa−1 at 0–50 kPa), a wide detection range (0–220 kPa), a fast response time of 56 ms, an ultra-low detection limit (30 Pa), and excellent stability (8000 cycles). Additionally, the e-skin exhibits positive temperature coefficients (0.0025 ℃-1) within 20–100 ℃, a rapid response time of 2.57 s, an extremely low detection limit (1 ℃), and stability after 50 cycles. Crucially, our intelligent e-skin system, employing a Long Short-Term Memory algorithm, enables real-time multi-modal tactile perception, accurately separating mixed pressure and temperature signals. This versatile technology holds immense potential for applications in intelligent robotics and human health monitoring.

In the study, we have fabricated Ag@Li dual shell hallow nanosphere (Ag@Li DSHN) by chemical reduction method for the dual non-enzymatic detection of glucose and phosphorus. TEM image of Ag@Li DSHN confirms the dual shell hallow nanosphere with Li core and Ag shell. The XRD spectrum of Ag@Li DSHN shows the particle was crystalline in nature. The dual detection of glucose and phosphorus by Ag@Li DSHN showed high sensitivity, and selectivity as a potential sensing probe. Zeta potential and average particle size of Ag@Li DSNH was found to be − 32.9 mV ± 2.1 mV and 12 ± 1.3 nm respectively. The limit of detection of glucose and phosphorus by Ag@Li DSHN was 2.8 and 2.9 nM respectively. Furthermore, the environmental parameter (pH, temperature and saline concentration) on the detection of glucose and phosphorus by Ag@Li DSHN was studied. Additionally, the real sample detection by Ag@Li DSHN towards the detection of glucose and phosphorus was studied and the recovery % was from 97 to 99%. Hence, Ag@Li DSHN can be used for the effective detection of glucose and phosphorus form environmental sample. [ABSTRACT FROM AUTHOR]

A 1,2,3-triazole-based chemosensor is used for selective switching in logic gate operations through colorimetric and fluorometric response mechanisms. The molecular probe synthesized via "click chemistry" resulted in a non-fluorescent 1,4-diaryl-1,2,3-triazole with a phenol moiety (PTP). However, upon sensing fluoride, it TURNS ON the molecule's fluorescence. The TURN-OFF order occurs through fluorescence quenching of the sensor when metal ions, e.g., Cu2+, and Zn2+, are added to the PTP-fluoride ensemble. A detailed characterization using Nuclear Magnetic Resonance (NMR) spectroscopy in a sequential titration study substantiated the photophysical characteristics of PTP through UV-Vis absorption and fluorescence profiles. A combination of fluorescence OFF-ON-OFF sequences provides evidence of 1,2,3-triazoles being controlled switches applicable to multimodal logic operations. The "INH" gate was constructed based on the fluorescence output of PTP when the inputs are F− and Zn2+. The "IMP" and "OR" gates were created on the colorimetric output responses using the probe's absorption with multiple inputs (F− and Zn2+ or Cu2+). The PTP sensor is the best example of the "Write-Read-Erase-Read" mimic. [ABSTRACT FROM AUTHOR]

Adiimine-based dualfluorescence sensor (APC) for selective detection of OCl− and Al3+ in lettuce and marigold sapling respectively. [Display omitted] • A noble, dual-target fluorescent chemosensor APC (anthracene-pyridine conjugate) has been synthesized for the prompt detection of Al3+ and ClO−. • APC interacts with both Al3+ and ClO− through charge transfer and chemodosimetric mechanisms to display green and blue fluorescence. • Among the five synthesized diimine-based fluorescent chemosensors analouges only APC shows a unique and efficient character for dual-target. • The sensing mechanisms of APC with Al3+ and ClO− have been established by UV–visible, 1H NMR titration, HRMS analysis and theoretical calculations. • APC has been successfully employed to examine the concentrations of aluminium and hypochlorite on marigold and lettuce plants, respectively. Aluminium (Al3+) and hypochlorite (ClO−) have toxic effects on plants, affecting various physiological processes and ultimately impacting plant growth and development. Hence, the preparation of a smart tool for the detection of hypochlorite (ClO−) and Aluminium (Al3+) in water, a dual-target fluorescent chemosensor APC (anthracene-pyridine conjugate) has been synthesized. APC holds a unique diimine character when compared with a few similar diimine and interacts with both Al3+ and ClO− through charge transfer and chemodosimetric mechanisms to display green and blue fluorescence, correspondingly.The detection limits of APC for Al3+ and ClO− are 0.68 µM and 0.25 µM, respectively. The binding ratio between APC and Al3+ has been determined as 1:1 from Jobs plot analysis. The sensing mechanisms of APC with Al3+ and ClO− have been established by UV–visible, 1H NMR titration, HRMS analysis and theoretical calculations. This method has been successfully employed to examine the consequences of continued exposure to high concentrations of aluminium and hypochlorite on marigold and lettuce plants, respectively. [ABSTRACT FROM AUTHOR]

The transformation of normal cells into cancer cells is a complex process, often accompanied by changes in the cellular microenvironment. As two key parameters of the cellular microenvironment, viscosity and pH have the potential to serve as cancer markers. Therefore, their simultaneous detection is of great significance for a more accurate understanding of cancer occurrence, development, metastasis, and treatment. To achieve dual detection of viscosity and pH, various fluorescence molecules have been designed, which can be classified into the following categories based on their sensitive sites: amine, phenolic hydroxyl, spiro-oxazolidine, and spiropyran. In addition to systematically comparing the design strategies, sensing mechanisms, and biological applications of these probes, this paper also highlights their limitations and potential future avenues of exploration. This may facilitate the design of more powerful fluorescent probes for diagnosing related diseases. • The first review about fluorescent probes that simultaneously detect pH and viscosity. • This review systematically comparing the design strategies, optical signals, sensing mechanisms and biological applications of the developed fluorescent probes. • This review contributes to the design of powerful fluorescent probes for simultaneous monitoring of multiple microenvironmental events. [ABSTRACT FROM AUTHOR]

New eco‐friendly carbon dot structures (CDs) were synthesized with hydrothermal method from ocimum basilicum in a single step. Structure, morphology and optical analyzes of these new CDs were performed with TEM, XRD, FTIR, XPS, UV‐Vis. absorption and steady‐state fluorescence measurements. It was determined that nano‐sized CDs structures with high fluorescence properties were obtained by the analysis results. The sensor application of CDs was studied using various metal ions with different charges. The results showed that these ocimum basilicum based CDs were sensitive and selective only for Fe3+ and Al3+ ions. LOD values of Fe3+ and Al3+ ions were calculated as 0.12 μM and 0.78 μM, respectively. As a result of interference and response time studies, it was determined that CDs have a highly selective and rapid response for Fe3+ and Al3+ ions. It was observed that CDs have practical applicability with real sample tests. The results obtained showed that this new CDs exhibit both "turn‐off" (for Fe3+ ions) and "turn‐on" (for Al3+ ions) detection simultaneously. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS), reactive sulfur species (RSS), metal ions, and nitrogen species (RNS) play important roles in a variety of biological processes, such as a signal transduction, inflammation, and neurodegenerative damage. These species, while essential for certain functions, can also induce stress-related diseases. The interrelation between ROS, RSS, Metal ions and RNS underscores the importance of quantifying their concentrations in live cells, tissues, and organisms. The review emphasizes the use of small-molecule-based fluorescent/chemodosimeter probes to effectively measure and map the species' distribution with high temporal and spatial precision, paying particular attention to in vitro and in vivo environments. These probes are recognized as valuable tools contributing to breakthroughs in modern redox biology. The review specifically addresses the relationship of HOCl/ClO‾ (hypochlorous acid/Hypochlorite) with other reactive species. (Dual sensing probes). [Display omitted] • Dual sensing probes for HOCl and other various ROS, RNN, RSS. • Discussion over the response resources, target, and probes recognition method. • Future development of fluorescent probes were proposed. [ABSTRACT FROM AUTHOR]

The present study aimed to develop a carbon dots-based fluorescence (FL) sensor that can detect more than one pollutant simultaneously in the same aqueous solution. The carbon dots-based FL sensor has been prepared by employing a facile hydrothermal method using citric acid and ethylenediamine as precursors. The as-synthesized CDs displayed excellent hydrophilicity, good photostability and blue fluorescence under UV light. They have been used as an efficient "turn-off" FL sensor for dual sensing of Fe3+ and Hg2+ ions in an aqueous medium with high sensitivity and selectivity through a static quenching mechanism. The lowest limit of detection (LOD) for Fe3+ and Hg2+ ions was found to be 0.406 µM and 0.934 µM, respectively over the concentration range of 0-50 µM. Therefore, the present work provides an effective strategy to monitor the concentration of Fe3+ and Hg2+ ions simultaneously in an aqueous medium using environment-friendly CDs. [ABSTRACT FROM AUTHOR]

The photochemistry of an expired Alpha Lipoic Acid-based drug namely MEGO-XL (ML) was investigated. ML showed its application in selective sensing of Fe3+ and Pb2+ avoiding any interference. The lower detection limit values for Fe3+ (1.51 × 10−4 M) and Pb2+ (72.8 µM) suggested the sensitive nature of ML. The stability of the compound was examined under different environmental conditions. Further, the interaction between ML and Fe3+, Pb2+ was studied with the help of Stern–Volmer plots, Benesi–Hildebrand relation. Increased KSV values with increased temperature suggested that the nature of quenching was purely dynamic in the case of Fe3+ and decreased KSV values with increased temperature indicated that there might be an occurrence of static quenching in the case of Pb2+. Ethylenediaminetetra acetic acid (EDTA) was used to differentiate the detection of Fe3+ from Pb2+.ML also showed application in sensing TiO2 nanoparticles and in OR logic gate operations. These experimental outcomes hinted that the chosen expired drug ML can be reused for chemosensing and logic gate applications. The dual-sensing nature [Fe(III) and Pb(II)] of ML is described through Intensity Vs Wavelength graphs. TiO2 sensing nature of ML is also described by KSV graph. The logic gate application of ML is pictorially represented with a truth table and bar graph. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development and identification of a novel ion pair sensor H 2 L via supramolecular assembly. • As an ion pair, the probe can detect ZnCl 2 and AlCl 3 in 9:1 DMSO-water medium. • In a pure aqueous medium, it can detect Cl− among several competitive anions. • 1:1 probe analyte binding is confirmed by the mass and NMR spectral study. • The probe can detect and quantify the Al in the market-available drug samples. The work reports the development of a novel pyridine 2, 6 diamide spacer acyl hydrazone-based dual sensor H 2 L via two intermediates 1 and 2. The sensor as well as intermediates have been spectroscopically characterized. The structure of intermediate 1 is validated by its single crystal data analysis. As H 2 L bears both amide and acyl hydrazone moiety which have selective detection ability of anion and cation respectively, after rigorous characterization, the sensors are exposed to check their dual binding behavior. The results of several spectroscopic studies disclose the fact that H 2 L can optically and fluorometrically detect Al (III) and Zn (II) among several competitive cations and Cl− among competitive anions in semi-aqueous and aqueous medium respectively. Interestingly in a 9:1 DMSO-water medium, the probe can act as an ion pair sensor and in this medium, the probe can simultaneously detect Zn (II)/Cl- and Al (III)/Cl- forming H 2 L-ZnCl 2 , H 2 L-AlCl 3 adduct. The 1:1 probe-analyte ion-pair binding is confirmed by NMR and mass spectral study. The Density Functional Theory (DFT) study optimizes the structures of the probe-analyte complexes. Impressively the probe has the potential to detect and quantify the Al (III) from market-available drug samples. [ABSTRACT FROM AUTHOR]

Organic/inorganic hybrid nanostructures-based dual light-detecting/gas-sensing devices were fabricated. In this research, polycrystalline perylene diimide (PDI) membrane was coated on ZnO nanorods (NRs), functioning as sensing nanocomposites. Multiple material analyses including scanning electron microscope (SEM), energy dispersive spectrometer (EDS), high resolution transmission electron microscopy (HR-TEM), X-ray diffractometer (XRD), Raman spectroscopy, and confocal laser scanning microscopy (CLSM) indicate that organic perylene diimide was successfully deposited on ZnO NRs, forming organic/inorganic membrane on the sensing device. To examine the influence of organic/inorganic hybrid nanostructure on photo-sensing and gas-sensing behaviors, UV light detection and CO gas sensing impulse response were measured. Results reveal that organic/inorganic hybrid nanostructure can effectively enhance UV light and CO gas dual-sensing properties with addition of PDI. The coating of organic PDI on the ZnO NRs not only improves the gas interaction capability and gas-sensing stability but also enhances the UV absorption efficiency. Owing to advantages of low cost, simple fabrication, compact size, and device stability, hybrid PDI/ZnO organic/inorganic light/gas dual-sensing devices are promising for future portable hazardous light and gas sensing applications.

In this study, ZnO/ZnS nanocomposite-based dual UV light/CO gas sensing devices have been demonstrated for the first time. To characterize the nanocomposites, multiple material characterizations indicated ZnS/ZnO core-shell rods were successfully formed on SiO2 substrates. Moreover, CO gas sensing and UV light detection measurements both revealed that incorporation of a ZnS shell on ZnO nanorods (NRs) can effectively increase gas sensing and light detection capabilities. Owing to their compact size, low cost, and simple fabrication, ZnO/ZnS NR-based gas and light dual-sensing devices show promises in hazardous gas and light monitoring. [ABSTRACT FROM AUTHOR]

A flexible nano-engineered natural mineral (carbon dot doped natural microcline) based membrane (MCPV) has been developed, which can efficiently detect the presence of hexavalent chromium (Cr6+) and trivalent iron (Fe3+) ions in water by altering its fluorescence emission. Detailed characterization of the membrane was carried out using XRD, FT-IR spectroscopy, FESEM, TEM, and UV-Vis spectroscopy. Mechanical and temperature stabilities were also investigated. This new-generation sensor membrane is designed in such a way that it does not dissolve in water, keeping the water quality unaffected. The fluorescence studies were conducted at 414 nm and "turn-off" response was observed specifically for Fe3+ at 489 nm. A prominent red shift (530 nm) of the fluorescence maxima takes place when it comes to Cr6+. Figures of merit, such as LOD (8.7 μM for Cr6+ and 18.4 μM for Fe3+) and LOQ (29.1 μM for Cr6+ and 61.6 μM for Fe3+), were evaluated from the linear range (0–60 μM for Cr6+ and 0–30 μM for Fe3+) of the calibration curve (Stern-Volmer plots) showing high sensitivity of this sensing probe toward Cr6+ and Fe3+. Recovery and RSD calculations were done in various real-life water samples on intraday-interday basis to determine the accuracy of the sensor. This work validates the fact that the synthesized sensor membrane is capable of detecting these heavy metals in glutathione environment as well, which could be beneficial for early-stage carcinogen detection in living cells. [ABSTRACT FROM AUTHOR]

This paper presents a 32 × 32 ISFET array with in-pixel dual-sensing and programmability targeted for on-chip DNA amplification detection. The pixel architecture provides thermal and chemical sensing by encoding temperature and ion activity in a single output PWM, modulating its frequency and its duty cycle respectively. Each pixel is composed of an ISFET-based differential linear OTA and a 2-stage sawtooth oscillator. The operating point and characteristic response of the pixel can be programmed, enabling trapped charge compensation and enhancing the versatility and adaptability of the architecture. Fabricated in 0.18  $\mu \rm{m}$ standard CMOS process, the system demonstrates a quadratic thermal response and a highly linear pH sensitivity, with a trapped charge compensation scheme able to calibrate 99.5% of the pixels in the target range, achieving a homogeneous response across the array. Furthermore, the sensing scheme is robust against process variations and can operate under various supply conditions. Finally, the architecture suitability for on-chip DNA amplification detection is proven by performing Loop-mediated Isothermal Amplification (LAMP) of phage lambda DNA, obtaining a time-to-positive of 7.71 minutes with results comparable to commercial qPCR instruments. This architecture represents the first in-pixel dual thermo-chemical sensing in ISFET arrays for Lab-on-a-Chip diagnostics. [ABSTRACT FROM AUTHOR]

ZnO/ZnS nanocomposite-based nanostructures exhibit dual light and gas sensing capabilities. To further boost the light/dual sensing properties, gold nanoparticles (Au NPs) were incorporated into the core-shell structures. Multiple material characterizations revealed that Au NPs were successfully well spread and decorated on ZnO/ZnS nanostructures. Furthermore, our findings show that the addition of Au NPs could enhance both 365 nm UV light sensing and hydrogen gas sensing in terms of light/gas sensitivity and light/gas response time. We postulate that the optimization of gas/light dual sensing capability may result from the induced electric field and inhabitation of electron-hole recombination. Owing to their compact size, simple fabrication, and stable response, ZnO/ZnS/Au NPs-based light/gas dual sensors are promising for future extreme environmental monitoring.

MicroRNAs (miRNAs) are small non-coding RNAs, which are involved in RNA silencing and post-transcriptional regulation of gene expression. Numerous studies have determined the expression of certain miRNAs in specific tissues and cell types, and their aberrant expression is associated with a variety of serious diseases such as cancers, immune-related diseases, and many infectious diseases. This suggests that miRNAs may be attractive and promising non-invasive biomarkers of diseases. In this study, we established a graphene oxide (GO)-based fluorescence/colorimetric dual sensing platform for miRNA by using a newly designed probe. The probe was designed to form a hairpin-like configuration with a fluorescent dye-labeled long tail, possessing a guanine (G)-rich DNAzyme domain in the loop region and target binding domain over the stem region and tail. By introducing this new hairpin-like probe in a conventional GO-based fluorescence platform, we observed both the miRNA-responsive color change by direct observation and sensitive fluorescence increase even below the nanomolar levels in a single solution without an additional separation step. [ABSTRACT FROM AUTHOR]

Abstract In this work, a sulfone-functionalized metal organic frameworks (MOFs) (CAU-11) formulated as [Al(OH)(SDBA)]·0.25DMF (H 2 SDBA = 4, 4′-sulfonyldibenzoic acid) has been successfully constructed under solvothermal conditions. Next, a europium ion post-functionalized compound (Eu3+@CAU-11) with bright red fluorescence has been obtained by postsynthetic modification (PSM). Because of its excellent luminescence and robust framework, we design this compound as a ratiometric fluorescent probe (I L / I Eu) for sensing application. In the investigation process, what is surprising is that Fe3+ can quench the fluorescence of Eu3+@CAU-11 both in aqueous solutions and in N, N-dimethylformamide (DMF) while Cu2+ can only quench the fluorescence of it in DMF. It represents a rare example of a sensor based on a metal-organic framework which can dually sense and distinguish two quenching metal ions in different solutions simultaneously. To better explain this phenomenon, the probable sensing mechanism of the two metal ions has also been discussed in this paper. More importantly, we have designed this ratiometric fluorescent sensor as a combinational molecular logic gate for further logical application because of its sample synthesis process and favorable luminescent properties. Graphical abstract fx1 Highlights • A Eu3+ postsynthetic modified (PSM)a sulfone-functionalized MOFs (CAU-11) as probe. • A ratiometric fluorescent probe (I L / I Eu) for sensing metal ions both in aqueous solutions and in DMF (N, N-dimethylformamide). • An effective sensor for detecting Fe3+ and Cu2+. • Cu2+ has different fluorescence responses in different solvents. • A combinational logic gate to distinguish these two quenching ions. [ABSTRACT FROM AUTHOR]

Abstract A new colorimetric styryl-benzimidazole based receptor to recognize more than one analyte trans -2-[4′−(dimethylamino)styryl]benzimidazole) (L1) has been synthesized and fully characterized by 13C and 1H NMR, elemental analysis, UV–vis spectroscopy, and HRMS. Investigation of sensing ability of receptor L1 was carried out in presence of multiple anions (Br−, CN−, Cl−, ClO 4 −, F−, HSO 4 −, PF 6 −, NO 3 −, S2−, OH−, AcO− and H 2 PO 4 −) and cations (Cu2+, Cr3+, Al3+, Mg2+, Cd2+, Ni2+, Fe3+, K+, Fe2+, Mn2+, Ag+, Hg2+, Ca2+, Co2+, Pb2+, Na+, and Zn2+) by using UV–vis spectroscopy. Receptor L1 showed colorimetric response towards only for HSO 4 − ion. Receptor L1 -HSO 4 − interaction confirmed with the help of 1H NMR titration. Among various cations, L1 selectively sense the Cu2+ and Al3+ with the drastic colour change from yellow to green and dark yellow respectively. The stoichiometric binding ratio of L1 with HSO 4 −, Cu2+, and Al3+ found to be 1:1 by jobs method and HRMS data proved the complex formation between L1 and Cu2+/Al3+ with very low detection limit. In addition to explore practical applicability of L1 , paper strips have been made and used to detect HSO 4 − and Cu2+ ions, respectively, up to 10 ppm level. Graphical Abstract Unlabelled Image Highlights • A new colorimetric styryl-benzimidazole based receptor L1 has been synthesized to recognize more than one analyte. • Receptor L1 showed colorimetric response towards only for HSO 4 − ion in presence of multiple anions. • Among various cations, L1 selectively sense the Cu2+ and Al3+ with the drastic colour change. • To explore practical applicability of L1 , paper strips have been made and used to detect HSO 4 − and Cu2+ ions, respectively, up to 10 ppm level. [ABSTRACT FROM AUTHOR]

In this work, we present a gold-coated shallow-tapered chirped fiber Bragg grating (stCFBG) for dual refractive index (RI) and temperature sensing. The stCFBG has been fabricated on a 15-mm long chirped FBG, by tapering a 7.29-mm region with a waist of 39 μm. The spectral analysis shows two distinct regions: a pre-taper region, in which the stCFBG is RI-independent and can be used to detect thermal changes, and a post-taper region, in which the reflectivity increases significantly when the RI increments. We estimate the RI and thermal sensitivities as 382.83 dB/RIU and 9.893 pm/°C, respectively. The cross-talk values are low (−1.54 × 10−3 dB/°C and 568.1 pm/RIU), which allows an almost ideal separation between RI and thermal characteristics. The stCFBG is a compact probe, suitable for long-term and temperature-compensated biosensing and detection of chemical analytes.

Highlights • Sensitive ultraviolet absorption based spectroscopy measurements of oxygen was reported. • An invariable absorption line shape based pressure measurement approach was designed. • A simplified, portable, and highly sensitive dual sensing system for oxygen and pressure was built. • Oxygen concentration detection limit of 150 ppm and pressure detection limit of 180 Pa were achieved. Abstract In this study, a highly sensitive monitoring system for dual sensing of oxygen and pressure has been developed. The absorption of oxygen in the wavelength range of 186–196 nm was observed and the corresponding absorption cross-section of oxygen in this band was achieved. An approach based on differential optical absorption spectroscopy was used to describe the concentration of oxygen. The detection limit of oxygen was determined to be 150 ppm per meter. No relation between pressure and oxygen absorption line shape in the related wavelength band was confirmed. Based on the absorption of oxygen, pressure detection was realized and a detection limit of 180 Pa was obtained. A dual sensing system for oxygen and pressure was constructed. [ABSTRACT FROM AUTHOR]

To avoid the sudden failure of mechanical structures under repeated loading and to supplement conventional methods of managing life time, we propose a failure detection technique under random fatigue loading using machine learning and dual sensing on a symmetric structure. The state of a shackle, which is used to connect the cargo to the hoist efficiently, under fatigue loading was collected using two strain sensors of a dual system. The strains were preprocessed and labeled as normal or abnormal. Logistic regression machine learning was employed to determine the decision boundary line. Then, we gathered the decision boundary lines of each experiment for determining the time of failure, and we verified every experiment with the most conservative decision boundary line. The results indicate that failure was detected before the crack occurred and the time to notice maintenance could be controlled. [ABSTRACT FROM AUTHOR]

• A photochromic AIEE diarylethene avoiding huge π-conjugate system has been synthesized. • A reaction-based dual sensing cyanide with excellent selectivity, and rapid response. • Application in detecting cyanide in food and water samples. An aldehyde-containing diarylethene parent react with the benzothiazole acetonitrile which results in a photochromic aggregation-induced emission enhancement (AIEE) molecule. The title compound emits bright yellow fluorescence (λ em = 578 nm) in the solid state, which is contrast to many diarylethene derivatives having serious aggregation-caused quenching (ACQ). Further studies showed the title compound as colorimetric and fluorescent sensing cyanide sensor based on nucleophilic addition reaction with rapid response, excellent selectivity, and high sensitivity. Moreover, practical applications studied showed the title compound is convenient to detect for cyanide ion in food and actual water samples. [ABSTRACT FROM AUTHOR]

In this study, a simple and cost-effective technique to fabricate a plastic optical fiber sensor for the dual sensing of hydrogen peroxide (H 2 O 2 ) and dissolved oxygen (DO) was described. The optical fiber dual sensor consisted of CdSe/ZnS core–shell quantum dots (QDs), with oxygen indicators coated on the fiber end of the sensor. An ethyl cellulose (EC) matrix doped with CdSe/ZnS QDs and tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) (Ru(dpp) 3 2+ ) served as the sensing materials for H 2 O 2 and DO. The sensing materials for H 2 O 2 and DO were excited with an light emitting diode (LED) of 405 nm, and the two emission wavelengths were separately detected. The optical fiber dual sensor was applied for the monitoring of different H 2 O 2 and DO concentrations. The typical Stern–Volmer plot of an optical fiber dual sensor for the sensing of DO demonstrated linearity, and the attenuation of the relative phosphorescence intensity for the sensing of H 2 O 2 concentrations also demonstrated linearity with the H 2 O 2 concentrations in the tested range. In addition, the results indicated that the phosphorescence properties of the H 2 O 2 sensor are independent of the presence of the DO sensor, with a unique linear response in the range of 0–132 mM. Finally, the DO sensing scheme described herein was intended to compensate for the H 2 O 2 concentration, and the fabricated optical fiber dual sensor may be used for the sensing of H 2 O 2 concentration and DO in the aquaculture applications. [ABSTRACT FROM AUTHOR]

An efficient fluorescein based probe (H 2 L) for the dual sensing of Al 3+ and Cu 2 + has been synthesized and characterized. H 2 L was highly selective toward these two ions with different fluorescence signals and binding modes in two different media. In EtOH-H 2 O (3:2, v/v; pH 4.0), H 2 L selectively binds Al 3+ to form a 1:1 ligand/metal complex, giving rise to a visible pale pink-to-yellow color change and fluorescence enhancement at 440 nm, while in CH 3 CN-H 2 O (2:3, v/v; pH 7.2), H 2 L and Cu 2+ form a 1:2 ratio complex, resulting in a color change from pink to orange-yellow and a significant fluorescence enhancement at 520 nm. The binding modes were confirmed by fluorescence, absorption, IR, ESI-MS and 1 H NMR titrations. The detection limits were calculated to be 7.32 × 10 −8 M and 1.47 × 10 −8 M for Al 3+ and Cu 2+ , respectively. Cell imaging studies demonstrate that this sensor is capable of sensing Al 3+ and Cu 2+ in living cells. [ABSTRACT FROM AUTHOR]

A simple naphthalene based fluorescent probe was first time reported as dual sensing of 2,4,6-trinitrotolune (TNT) and 2,4,6-trinitrophenol (TNP) by distinguishable changes in both solution color change and fluorescence within same sample without any mask agent. Upon addition of TNT and TNP, the strong emission quenching at 412 nm and a new emission band at 530 nm was observed, respectively. In addition, the sensing mechanism was evaluated by DFT calculations by Gaussian 09 software. [ABSTRACT FROM AUTHOR]

Disposable screen-printed carbon arrays modified with gold nanoparticles (AuNPs) are described. The AuNP-modified screen-printed carbon arrays, designated as AuNP-SPCE arrays, were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The AuNP-SPCE arrays display excellent electrocatalytic activity towards lead and copper. Two well-defined and fully resolved anodic stripping peaks, at 20 mV for Pb(II) and at 370 mV for Cu(II), both vs. Ag/AgCl, can be seen. Square wave anodic stripping voltammetry was used to simultaneously analyze Pb(II) and Cu(II) in their binary mixtures in tap water. The linear working range for Pb(II) extends from 10 μg.L to 100 μg.L with a sensitivity of 5.94 μA.μg.L.cm. The respective data for Cu(II) are a working range from 10 μg.L to 150 μg.L with a sensitivity of 3.52 μA.μg.L.cm. The limits of detection (based on 3× the baseline noise) are 2.1 ng.L and 1.4 ng.L, respectively. In our perception, this array is particularly attractive because Pb(II) and Cu(II) can be determined at rather low working potentials which makes the method fairly selective in that it is not significantly interfered by other electroactive species that require higher reduction potentials. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A simple, low-cost technique for fabricating a plastic optical fiber sensor for the dual sensing of dissolved oxygen (DO) and Cu 2+ ions is proposed. The optical fiber dual sensor consists of quantum dots (QDs) and oxygen indicator coated on the fiber end. A fluorinated xerogel doped with palladium (II) meso-tetrakis(pentafluorophenyl)porphyrin (PdTFPP) and CdSe QDs serves as the DO and Cu 2+ ion sensing material. The Cu 2+ ion and DO fluorescent indicators can both be excited with a 405-nm LED and the two emission wavelengths can be detected separately. The optical fiber dual sensor was tested with regard to monitoring various Cu 2+ ion and DO concentrations. The attenuation of the relative luminescence intensity for Cu 2+ ion sensing has a linear relationship with Cu 2+ ions in the tested range. In addition, the results show that the luminescence properties of the Cu 2+ ion sensor are independent of the presence of the DO sensor, and have a uniquely good linear response in the 0–10 μM range. The proposed optical fiber dual sensor can be used for the simultaneously sensing of Cu 2+ ion and DO concentrations in biological, medical, and environmental applications. [ABSTRACT FROM AUTHOR]

In this work, we present a new approach to prepare the Ag@CdS core–shell fluorescent nanoparticles wrapped with molecularly imprinted polymer for ferritin macromolecule by capping with vinyl derivative of cysteine. The imprinted Ag@CdS nanoparticle was prepared via activator regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP) method onto the surface of vinyl silane modified pencil graphite electrode. Combination of Ag and CdS in a single motif causes the dual behavior of core shell nanoparticle, which shows enhanced fluorescence as well as electrochemical properties. The performance of the obtained imprinted sensor was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, chronocoulometry, differential pulse voltammetry and fluorescence spectrophotometry. Under the optimal experimental conditions, the current response of the electrochemical sensor was linear to ferritin concentrations in the range from 1.99 to 23.43 µg L −1 , with the detection limit of 0.65 µg L −1 . Similarly, a linear response was obtained between fluorescence quenching of imprinted Ag@CdS and concentration of ferritin in the range from 4.0 to 91.0 µg L −1 , with limit of detection (LOD) of 1.3 µg L −1 . The method was successfully applied to the analysis of blood serum samples of five different men and women with acceptable recoveries of 99.7% and 100.3% (RSD in %=1.0–2.0). [ABSTRACT FROM AUTHOR]

Abstract: A simple, low cost technique to fabricate a plastic optical fiber sensor for dual sensing of temperature and oxygen has been described. The optical fiber dual sensor consists of temperature and oxygen indicators that were coated on the fiber end. A fluorinated xerogels doped with platinum tetrakis pentrafluoropheny porphine (PtTFPP) and 5(6)-carboxyfluorescein (CF) serves as the oxygen and temperature sensing material. The temperature and oxygen indicators can both be excited with an LED of 405nm, and the two emission wavelengths can be detected separately. The optical fiber dual sensor has been tested with regard to monitoring different temperatures and oxygen concentrations. The typical Stern–Volmer plot of an optical fiber dual sensor for oxygen sensing shows linearity, and the attenuation of the relative luminescence intensity for temperature sensing also has a linear relationship with temperature in the tested range. In addition, our results show that the luminescence properties of the temperature sensor are independent of the presence of the oxygen sensor, and have a uniquely good linear response in the 25–66°C range. Finally, the oxygen sensing scheme presented in this work is intended for use in temperature compensation, and optical fiber dual sensor can be used for the contactless-sensing of temperature and oxygen in biological, medical and environmental applications. [Copyright &y& Elsevier]

Abstract: A novel fluorescent probe for the copper(II) ion in mixed aqueous media, based on fluorescence quenching mechanism with noticeable color change from light to dark yellow, was designed and synthesized. It also exhibited high selectivity for acetate in acetonitrile over other common anions in the near infrared region (NIR) accompanied with exciting color changes from light yellow to pink. Hence sensor 1 ascertains its dual chemosensing ability toward Cu(II) and acetate ions as evidenced by competitive experiments. [Copyright &y& Elsevier]

Abstract: The salicylaldimine based colorimetric chemosensors R1 and R2 were synthesized and examined for anion and cation sensing property. The chemosensors R1 and R2 show visual changes towards biologically relevant anions like F− and OH− and also towards various cations such as Fe3+, Co2+, Ni2+, Cu2+ and Sn2+. The sensing action was further confirmed by UV–vis titration and fluorescence spectroscopic studies. The binding constant (K a ) and stoichiometry of host-guest complex formed were determined by Benesi–Hildebrand (B–H) plot and Job''s plot method, respectively. [Copyright &y& Elsevier]

Chemical sensing, imaging and microscopy based on the use of fluorescent probes has so far been limited almost exclusively to the detection of a single parameter at a time. We present a scheme that can overcome this limitation by enabling optical sensing of two parameter simultaneously and even at identical excitation and emission wavelengths of two probes provided (a) their decay times are different enough to enable two time windows to be recorded, and (b) the emission of the shorter-lived probe decays to below the detectable limit while that of the other still can be measured. We refer to this new scheme as the dual lifetime determination (DLD) method and show that it can be widely varied by appropriate choice of probes and experimental settings. DLD is demonstrated to work by sensing oxygen and temperature independently from each other by making use of two probes, one for oxygen (a platinum porphyrin dissolved in polystyrene), and one for temperature [a europium complex dissolved in poly(vinyl methylketone)]. DLD was applied to monitor the consumption of oxygen in the glucose oxidase-catalyzed oxidation of glucose at varying temperatures. The scheme is expected to have further applications in cellular assays and biophysical imaging. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

ZnO/ZnS nanocomposite-based nanostructures exhibit dual light and gas sensing capabilities. To further boost the light/dual sensing properties, gold nanoparticles (Au NPs) were incorporated into the core-shell structures. Multiple material characterizations revealed that Au NPs were successfully well spread and decorated on ZnO/ZnS nanostructures. Furthermore, our findings show that the addition of Au NPs could enhance both 365 nm UV light sensing and hydrogen gas sensing in terms of light/gas sensitivity and light/gas response time. We postulate that the optimization of gas/light dual sensing capability may result from the induced electric field and inhabitation of electron-hole recombination. Owing to their compact size, simple fabrication, and stable response, ZnO/ZnS/Au NPs-based light/gas dual sensors are promising for future extreme environmental monitoring. [ABSTRACT FROM AUTHOR]

In this work, we present a gold-coated shallow-tapered chirped fiber Bragg grating (stCFBG) for dual refractive index (RI) and temperature sensing. The stCFBG has been fabricated on a 15-mm long chirped FBG, by tapering a 7.29-mm region with a waist of 39 μm. The spectral analysis shows two distinct regions: a pre-taper region, in which the stCFBG is RI-independent and can be used to detect thermal changes, and a post-taper region, in which the reflectivity increases significantly when the RI increments. We estimate the RI and thermal sensitivities as 382.83 dB/RIU and 9.893 pm/°C, respectively. The cross-talk values are low (−1.54 × 10−3 dB/°C and 568.1 pm/RIU), which allows an almost ideal separation between RI and thermal characteristics. The stCFBG is a compact probe, suitable for long-term and temperature-compensated biosensing and detection of chemical analytes. [ABSTRACT FROM AUTHOR]

• Organic/inorganic hybrid nanostructures were grown on sensing chips. • ZnO-based light/gas dual-sensing devices were fabricated. • Incorporation of organic perylene diimide optimized the sensing behaviors. • Enhancement of carrier transition was observed inOrganic/inorganic interface. Organic/inorganic hybrid nanostructures-based dual light-detecting/gas-sensing devices were fabricated. In this research, polycrystalline perylene diimide (PDI) membrane was coated on ZnO nanorods (NRs), functioning as sensing nanocomposites. Multiple material analyses including scanning electron microscope (SEM), energy dispersive spectrometer (EDS), high resolution transmission electron microscopy (HR-TEM), X-ray diffractometer (XRD), Raman spectroscopy, and confocal laser scanning microscopy (CLSM) indicate that organic perylene diimide was successfully deposited on ZnO NRs, forming organic/inorganic membrane on the sensing device. To examine the influence of organic/inorganic hybrid nanostructure on photo-sensing and gas-sensing behaviors, UV light detection and CO gas sensing impulse response were measured. Results reveal that organic/inorganic hybrid nanostructure can effectively enhance UV light and CO gas dual-sensing properties with addition of PDI. The coating of organic PDI on the ZnO NRs not only improves the gas interaction capability and gas-sensing stability but also enhances the UV absorption efficiency. Owing to advantages of low cost, simple fabrication, compact size, and device stability, hybrid PDI/ZnO organic/inorganic light/gas dual-sensing devices are promising for future portable hazardous light and gas sensing applications. [ABSTRACT FROM AUTHOR]

This study presents a low-cost plastic optical fiber sensor for the dual sensing of temperature and oxygen. The sensor features commercially available epoxy glue coated on the side-polished fiber surface for temperature sensing and a fluorinated xerogel doped with platinum tetrakis pentrafluoropheny porphine coated on the fiber end for oxygen sensing. The temperature and oxygen indicators are both excited using an ultraviolet light-emitting diode light source with a wavelength of 380 nm. The luminescence emission spectra of the two indicators are well resolved and exhibit no crosstalk effects. Our studies show that the temperature response of the sensor is independent of the oxygen concentration. Overall, the results indicate that the dual sensor presented in this study provides an ideal solution for the noncontact, simultaneous sensing of temperature and oxygen in general biological and medical applications. [ABSTRACT FROM PUBLISHER]

As inspired by the recent reports that many unique properties can be achieved by using two dissimilar components to form heterostructures, especially for materials in nano-size. In this letter, one-dimensional ZnO–SnO 2 heterostructures were constructed by uniformly growing SnO 2 nanoparticles on the surfaces of ZnO nanowires. Compared with pure ZnO nanowires, ZnO–SnO 2 heterostructures exhibited significant enhancement in response and selectivity to NO 2 and ethanol. The excellent response/recovery characteristics and stability of ZnO–SnO 2 heterostructures demonstrate that the heterostructure construction is promising for dual sensing of NO 2 and ethanol using one sensor. The possible enhancement sensing mechanisms were discussed based on the depletion control and potential barrier control models. • A facile strategy was developed to synthesis core-shell-like ZnO–SnO 2 n-n hetero-structured nanowires. • ZnO–SnO 2 nanowires consisted of ZnO nanowires and ultra-fine SnO 2 nanoparticles. • The density of SnO 2 nanoparticles that grown on the surface of ZnO nanowires was controllable. • ZnO–SnO 2 hetero-structured nanowires exhibited an excellent dual-sensing ability to NO 2 and ethanol. [ABSTRACT FROM AUTHOR]

• Microwave sensor based on the split ring resonator has been proposed. • Detection of ε′ for two different liquid samples at two separate frequencies. • Detection of permittivity of one sample at two frequency bands. • The considered sensor advantages are high Q-factor, high sensitivity and compact. • Measuring of changes in glucose concentration in blood in the medical industry. In this paper, a microwave sensor based on the split ring resonator has been proposed to detect the real part of the dielectric constant of the liquid sample. The proposed structure composed of non-identical double-split ring resonators which are placed in the inner part of the power divider branches. The proposed sensor has two purposes: (1) Measurement of the permittivity of one sample under test in two frequency bands (multi-band), (2) Dual samples under test for simultaneous dielectric detection (multi-sensing). There are several advantages in measuring the permittivity of the sample under test with the proposed sensor such as high Q-factor, high sensitivity, compact size, multi-sensing and multi-band. This paper investigates resonance frequency variation relative to the samples with different permittivities, such as ethanol, methanol, glucose solution and deionized water compared to previous similar works in simulation and experimental results. The permittivity of samples under test varies from 24 to 78 at 25 ˚C, and the simulated sensor resonance frequency would change about from 5.76 to 4.8 GHz at first resonance frequency and 7.85 to 6.35 GHz at second resonance frequency. [ABSTRACT FROM AUTHOR]