A double-conducting polymer nanowire-based electrochemical aptasensor for highly sensitive and low fouling detection of cortisol in saliva.

A cortisol biosensor was developed based on double-conducting polymer nanowires, which exhibits excellent conductivity, resistance to biological contamination, and outstanding sensing performance. The biosensor employs dual-mode electrochemical techniques, namely, differential pulse voltammetry (DPV) and chronoamperometry (CA), for the sensitive and low fouling detection of the glucocorticoid hormone cortisol. Experimental results demonstrated that the linear detection range of the biosensor in DPV mode was 1.0 × 10-14-1.0 × 10-8 M, with a detection limit of 0.131 × 10-14 M. In CA mode, the biosensor exhibited a detection range of 1.0 × 10-13-1.0 × 10-7 M and a detection limit of 0.313 × 10-13 M. The biosensor was successfully utilized for the rapid detection of cortisol in human saliva. The combination of a high-specificity cortisol aptamer and functionalized double-conducting polymer nanowires ensured the exceptional specificity and sensitivity of the biosensor in detecting real biological samples.

Cu Nanowires Trigger Efficient Cuproptosis via Special Intracellular Distribution and Excessive Cu Ion Release.

Cuproptosis, dependent on Cu overload, presents novel opportunities for cancer therapy. Cu-based nanomaterials have shown excellent advantages for the intracellular delivery of Cu. However, the biological process of Cu nanomaterials transporting Cu ions into cancer cells remains unclear. In this study, we tracked the Cu ion release process of copper nanowires (CuNWs) and copper nanoparticles (CuNPs) at the single-cell level. CuNWs with 5-µm length and CuNPs were found to be completely internalized by cancer cells. Interestingly, CuNWs escaped from the endolysosomal system, whereas CuNPs were mainly trapped in the lysosomes. This specific intracellular distribution of CuNWs led to cytoplasmic Cu ion overload, directly damaging mitochondria and inducing dihydrolipoamide S-acetyltransferase (DLAT) protein aggregation. Through these excessive Cu ions, CuNWs triggered more efficient cuproptosis than CuNPs to further increase cell death. Thus, CuNWs are more effective in delivering Cu ions than CuNPs, providing a novel perspective for designing cuproptosis-based functional nanomaterials for cancer therapy.

Dual-Function DNA Nanowires with Self-Feedback Amplification and Efficient Signal Transduction for Intracellular Imaging of MicroRNA-155.

Intracellular detection and imaging of microRNAs (miRNAs) with low expression usually face the problem of unsatisfactory sensitivity. Herein, a novel dual-function DNA nanowire (DDN) with self-feedback amplification and efficient signal transduction was developed for the sensitive detection and intracellular imaging of microRNA-155 (miRNA-155). Target miRNA-155 triggered catalytic hairpin assembly (CHA) to generate plenty of double-stranded DNA (dsDNA), and a trigger primer exposed in dsDNA initiated a hybridization chain reaction (HCR) between four well-designed hairpins to produce DDN, which was encoded with massive target sequences and DNAzyme. On the one hand, target sequences in DDN acted as self-feedback amplifiers to reactivate cascaded CHA and HCR, achieving exponential signal amplification. On the other hand, DNAzyme encoded in DDN acted as signal transducers, successively cleaving Cy5 and BHQ-2 labeled substrate S to obtain a significantly enhanced fluorescence signal. This efficient signal transduction coupling self-feedback amplification greatly improved the detection sensitivity with a limit of detection of 160 aM for miRNA-155, enabling ultrasensitive imaging of low-abundance miRNA-155 in living cells. The constructed DDN creates a promising fluorescence detection and intracellular imaging platform for low-expressed biomarkers, exhibiting tremendous potential in biomedical studies and clinical diagnosis of diseases.

A Calibration Strategy for Silicon Nanowire Field-Effect Transistor Biosensors and Its Application in Ultra-Sensitive, Label-Free Biosensing.

The silicon nanowire field-effect transistor (SiNW FET) has been developed for over two decades as an ultrasensitive, label-free biosensor for biodetection. However, inconsistencies in manufacturing and surface functionalization at the nanoscale have led to poor sensor-to-sensor consistency in performance. Despite extensive efforts to address this issue through process improvements and calibration methods, the outcomes have not been satisfactory. Herein, based on the strong correlation between the saturation response of SiNW FET biosensors and both their feature size and surface functionalization, we propose a calibration strategy that combines the sensing principles of SiNW FET with the Langmuir-Freundlich model. By normalizing the response of the SiNW FET biosensors (ΔI/I0) with their saturation response (ΔI/I0)max, this strategy fundamentally overcomes the issues mentioned above. It has enabled label-free detection of nucleic acids, proteins, and exosomes within 5 min, achieving detection limits as low as attomoles and demonstrating a significant reduction in the coefficient of variation. Notably, the nucleic acid test results exhibit a strong correlation with the ultraviolet-visible (UV-vis) spectrophotometer measurements, with a correlation coefficient reaching 0.933. The proposed saturation response calibration strategy exhibits good universality and practicability in biological detection applications, providing theoretical and experimental support for the transition of mass-manufactured nanosensors from theoretical research to practical application.

Precise control of transmembrane current via regulating bionic lipid membrane composition.

The transport of ions through biological ion channels is regulated not only by their structural characteristics but also by the composition of the phospholipid membrane, which serves as a carrier for nanochannels. Inspired by the modulation of ion currents by lipid membrane composition, exemplified by the activation of the K+ channel of Streptomyces A by anionic lipids, we present a biomimetic nanochannel system based on combining DNA nanotechnology with two-dimensional graphene oxide (GO) nanosheets. By designing multibranched DNA nanowires, we assemble programmable DNA scaffold networks (DSNs) on the GO surface to precisely control membrane composition. Modulating the DSN layers from one to five enhances DNA composition, yielding a maximum 12-fold enhancement in ion current, primarily due to charge effects. Incorporating DNAzymes facilitates reversible modulation of membrane composition, enabling cyclic conversion of ion current. This approach offers a pathway for creating devices with highly efficient, tunable ion transport, applicable in diverse fields like mass transport, environmental protection, biomimetic channels, and biosensors.

Highly Stretchable, Tissue-like Ag Nanowire-Enhanced Ionogel Nanocomposites as an Ionogel-Based Wearable Sensor for Body Motion Monitoring.

The development of wearable electronic devices for human health monitoring requires materials with high mechanical performance and sensitivity. In this study, we present a novel transparent tissue-like ionogel-based wearable sensor based on silver nanowire-reinforced ionogel nanocomposites, P(AAm-co-AA) ionogel-Ag NWs composite. The composite exhibits a high stretchability of 605% strain and a moderate fracture stress of about 377 kPa. The sensor also demonstrates a sensitive response to temperature changes and electrostatic adsorption. By encapsulating the nanocomposite in a polyurethane transparent film dressing, we address issues such as skin irritation and enable multidirectional stretching. Measuring resistive changes of the ionogel nanocomposite in response to corresponding strain changes enables its utility as a highly stretchable wearable sensor with excellent performance in sensitivity, stability, and repeatability. The fabricated pressure sensor array exhibits great proficiency in stress distribution, capacitance sensing, and discernment of fluctuations in both external electric fields and stress. Our findings suggest that this material holds promise for applications in wearable and flexible strain sensors, temperature sensors, pressure sensors, and actuators.

Robust Long-Nanowire Fabrication by Clean-Phase-Assisted Micro Chemical Pen for Enhanced Bioassay Sensitivity.

Long nanowires offer an increased surface area for biomolecule immobilization, facilitating enhanced binding capacity and sensitivity in the detection of target analytes. However, robust long-nanowire fabrication remains a significant challenge. In this paper, we developed a novel construction of a micro chemical pen (MCP), called a clean-assisted micro chemical pen (CAMCP), for robust long-nanowire fabrication. CAMCP, based on localized hydrodynamic flow confinement, was conducted by incorporating a clean phase to effectively dissolve aggregated silver particles in the aspiration channel's shell, thereby enhancing the MCP's longevity by 60.84%, allowing for an 840 µm extension in nanowire patterning capability. A 4600-aspect ratio (length:1200 µm, width: 260 nm) nanowire was fabricated by CAMCP and utilized as a nanowire sensor, showing a 39.7% increase in IgA detection sensitivity compared to a 3000-aspect ratio sensor. Furthermore, the longer nanowire sensor exhibited enhanced signal responses, a higher signal-to-noise ratio, and a lower limit of detection (LOD). The preponderant bioassay performances of the longer nanowire sensor in bioassays, facilitated by CAMCP, open up its possibilities for chemical-synthesis nanowires (NWs) in ultrasensitive biodetection.

Jellyfish-like Gold Nanowires as FlexoSERS Sensors for Sweat Analysis.

We introduce the FlexoSERS sensor, which is notable for its high stretchability, sensitivity, and patternability. Featuring a hierarchically oriented jellyfish-like architecture constructed from stretchable gold nanowires, this sensor provides an ultrasensitive SERS signal even under 50% strain, with an enhancement factor (EF) of 3.3 × 1010. Impressively, this heightened performance remains consistently robust across 2,500 stretch-release cycles. The integration of nanowires with 3D-printed hydrogel enables a customizable FlexoSERS sensor, facilitating localized sweat collection and detection. The FlexoSERS sensor successfully detects and quantifies uric acid (UA) in both artificial and human sweat and functions as a pH sensor with repeatability and sensitivity across a pH range of 4.2-7.8, enabling real-time sweat monitoring during exercise. In summary, the rational architectural design, scalable fabrication process, and hydrogel integration collectively position this nanowire-based FlexoSERS sensor as a highly promising platform for customizable wearable sweat diagnostics.

Ultrathin and highly flexible layered silver nanowires/carboxymethyl cellulose nanofiber nanocomposite films for electromagnetic interference shielding.

Lightweight, flexible, efficient and easy-to-manufacture electromagnetic interference (EMI) shielding materials are in urgent demand in the communications industry, artificial intelligence and wearable electronics. Based on the large size difference between one-dimensional carboxymethyl cellulose nanofibers (CMC) and large-diameter silver nanowires (AgNWs), layered AgNWs/CMC nanocomposite films with large effective thickness, and high conductivity were first prepared by a simple one-step vacuum filtration self-assembly technique. The unique layered structure of the AgNWs/CMC nanocomposite film significantly enhances the conductive pathways within the film, endowing it excellent EMI shielding performance. The results show that the conductivity of the ultra-thin film with a thickness of 20 µm is 3.72 × 106 S/m, and the EMI SE in the X-band is 87.7 dB, which can effectively shield electromagnetic signals in mobile communications. Furthermore, the AgNWs/CMCs nanocomposite films exhibit excellent thermal management performance, which can be heated to 100-180 °C within 10 s at a low voltage of 1.5 V. In particular, this nanocomposite film with a new layered structure provides a noval preparation idea for future EMI shielding materials and wearable heating devices.

Analysis of structural defects and their influence on red-emitting γ-Al2O3:Mn4+,Mg2+ nanowires using positron annihilation spectroscopy.

The present paper reported on the analysis of structural defects and their influence on the red-emitting γ-Al2O3:Mn4+,Mg2+ nanowires using positron annihilation spectroscopy (PAS). The nanowires were synthesized by hydrothermal method and low-temperature post-treatment using glucose as a reducing agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and photoluminescence excitation (PLE) were utilized, respectively, for determining the structural phase, morphology and red-emitting intensity in studied samples. Three PAS experiments, namely, positron annihilation lifetime (PAL), Doppler broadening (DB), and electron momentum distribution (EMD), were simultaneously performed to investigate the formations of structural defects in synthesized materials. Obtained results indicated that the doping concentration of 0.06% was optimal for the substitution of Mn4+ and Mg2+ to two Al3+ sites and the formation of oxygen vacancy (VO)-rich vacancy clusters (2VAl + 3VO) and large voids (~0.7 nm) with less Al atoms. Those characteristics reduced the energy transfer between Mn4+ ions, thus consequently enhanced the PL and PLE intensities. Moreover, this optimal doping concentration also effectively controlled the size of nanopores (~2.18 nm); hence, it is expected to maintain the high thermal conductivity of γ-Al2O3 nanowire-phosphor. The present study, therefore, demonstrated a potential application of γ-Al2O3 nanowire-phosphor in fabricating the high-performance optoelectronic devices.

Colorimetric sensors constructed with one dimensional PtNi nanowire and Pt nanowire nanozymes for Hg2+ detection.

BACKGROUND: In recent years, environmental pollution has attracted widespread global attention. Among them, environmental problems caused by heavy metal pollution pose a serious threat to human health and ecosystems. Mercury is a common heavy metal pollutant with high toxicity and wide distribution. Excessive intake of Hg2+ can cause permanent and severe damage to the nervous system, respiratory system, and kidneys in the human body. Therefore, developing both accurate and fast detection methods for Hg2+ is of great significance. RESULTS: A sensitive Hg2+ colorimetric sensor is designed based on PtNi nanowires (NWs) and Pt NWs with peroxidase-mimetic activity. PtNi NWs and Pt NWs catalyze the reaction of 3,3', 5,5'-tetramethylbenzidine (TMB) with hydrogen peroxide (H2O2) to produce blue oxidized TMB (oxTMB). The specific interaction of Pt-Hg significantly inhibits the peroxidase-mimetic activity of PtNi NW and Pt NW nanozymes, resulting in a lighter blue color. It is worth noting that compared with specific activity (SA) of Pt NWs (3.31 U/mg), PtNi NWs own superior SA (10.43 U/mg), which inevitably leads to a wider linear range of Hg2+ analysis (1 nM-200 µM) and a lower detection limit (0.6748 nM) for PtNi NWs-based colorimetric sensor, versus linear range (4 nM-5 µM) and LOD of 1.198 nM for Pt NWs-based colorimetric sensor, which are far below the Hg2+ threshold (10 nM) for drinking water set by the US Environmental Protection Agency. SIGNIFICANCE: The two nanozyme colorimetric sensors have been successfully used for the evaluation of Hg2+ in complex river water and tap water. Due to the advantages of simple operation, fast response, and high sensitivity, colorimetric sensors have broad application prospects in environmental monitoring.

Closed Bipolar Nanoelectrode Array for Ultra-Sensitive Detection of Alkaline Phosphatase and Two-Dimensional Imaging of Epidermal Growth Factor Receptors.

The combination of closed bipolar electrodes (cBPE) with electrochemiluminescence (ECL) imaging has demonstrated remarkable capabilities in the field of bioanalysis. Here, we established a cBPE-ECL platform for ultrasensitive detection of alkaline phosphatase (ALP) and two-dimensional imaging of epidermal growth factor receptor (EGFR). This cBPE-ECL system consists of a high-density gold nanowire array in anodic aluminum oxide (AAO) membrane as the cBPE coupled with ECL of highly luminescent cadmium selenide quantum dots (CdSe QDs) luminophores to achieve cathodic electro-optical conversion. When an enzyme-catalyzed amplification effect of ALP with 4-aminophenyl phosphate monosodium salt hydrate (p-APP) as the substrate and 4-aminophenol (p-AP) as the electroactive probe is introduced, a significant improvement of sensing sensitivity with a detection limit as low as 0.5 fM for ALP on the cBPE-ECL platform can be obtained. In addition, the cBPE-ECL sensing system can also be used to detect cancer cells with an impressive detection limit of 50 cells/mL by labeling ALP onto the EGFR protein on A431 human epidermal cancer cell membranes. Thus, two-dimensional (2D) imaging of the EGFR proteins on the cell surface can be achieved, demonstrating that the established cBPE-ECL sensing system is of high resolution for spatiotemporal cell imaging.

Customized Vascular Repair Microenvironment: Poly(lactic acid)-Gelatin Nanofibrous Scaffold Decorated with bFGF and Ag@Fe3O4 Core-Shell Nanowires.

Vascular defects caused by trauma or vascular diseases can significantly impact normal blood circulation, resulting in serious health complications. Vascular grafts have evolved as a popular approach for vascular reconstruction with promising outcomes. However, four of the greatest challenges for successful application of small-diameter vascular grafts are (1) postoperative anti-infection, (2) preventing thrombosis formation, (3) utilizing the inflammatory response to the graft to induce tissue regeneration and repair, and (4) noninvasive monitoring of the scaffold and integration. The present study demonstrated a basic fibroblast growth factor (bFGF) and oleic acid dispersed Ag@Fe3O4 core-shell nanowires (OA-Ag@Fe3O4 CSNWs) codecorated poly(lactic acid) (PLA)/gelatin (Gel) multifunctional electrospun vascular grafts (bAPG). The Ag@Fe3O4 CSNWs have sustained Ag+ release and exceptional photothermal capabilities to effectively suppress bacterial infections both in vitro and in vivo, noninvasive magnetic resonance imaging (MRI) modality to monitor the position of the graft, and antiplatelet adhesion properties to promise long-term patency. The gradually released bFGF from the bAPG scaffold promotes the M2 macrophage polarization and enhances the recruitment of macrophages, endothelial cells (ECs) and fibroblast cells. This significant regulation of diverse cell behavior has been proven to be beneficial to vascular repair and regeneration both in vitro and in vivo. Therefore, this study supplies a method to prepare multifunctional vascular-repair materials and is expected to represent a significant guidance and reference to the development of biomaterials for vascular tissue engineering.

Light-Driven Electrochemical Biosensing with DNA Origami-Assisted Hybrid Nanoantenna for Fumonisin B1 Monitoring.

The electrochemical detection of biosensors is largely governed by the changes in physical properties of redox probes, which are susceptible to electrode substrate effects, inhibiting sensor sensitivity. In this work, a light-driven electrochemical biosensor based on a hybrid nanoantenna was developed for the sensitive detection of fumonisin B1 (FB1). The hybrid nanoantenna sensing interface was constructed by coupling CdSe quantum dots (QDs)-DNA nanowire and graphdiyne oxide composites loaded with methylene blue and gold nanorods (GDYO-MB-Au NRs) using a tetrahedral DNA nanostructure, which acted as a light-driven unit and an amplification unit, respectively. The hybrid nanoantenna with light-driven properties facilitated the alteration in the chemical properties of MB at the sensing interface; that is, MB was degraded under light illumination. The stripping of the CdSe QDs-DNA nanowire triggered by the binding of FB1 could degrade the light-driven capability, thereby improving the electrochemical signal through depressing MB degradation. Taking advantage of the photodegradation of MB by the hybrid nanoantenna, the developed biosensor reduced the background signal and increased the detection sensitivity. The developed biosensor exhibited a linear detection range from 0.5 fg mL-1 to 10 pg mL-1 and a detection limit down to 0.45 fg mL-1. This strategy shows great promise for the fabrication of highly sensitive electrochemical biosensors.

Preparation of chitin twisted fiber and its functional applications.

Chitin has garnered significant attention due to its renewable, biocompatibility and biodegradability, while its practical application seriously hindered as the functionality of chitin itself can no longer meet people's increasing requirements for materials. Here, an effective method is successfully built for high-performance chitin fibers fabrication through a multi-step strategy that involved chemical pre-crosslinking, followed by wet-twisting and wet-stretching techniques, combined with physical cross-linking. The as-prepared chitin fiber exhibited a smooth surface, adjustable diameter, and mechanical strong properties (144.6 MPa). More importantly, functional chitin fiber with magnetic or conductive abilities can be easily obtained by spraying Fe3O4 particles or Ag nanowire on the chemical pre-crosslinking chitin gel film before stretching and twisting. The doped functional inorganic particles exist in a continuous ribbon structure in the fiber reduced the decrease in material strength caused by uneven particles dispersion, resulting 88.4 % of stress and 91.6 % of strain retention. This work not only bestow invaluable insights into the fabrication of functional chitin fibers but also provide a novel approach to solve the problem of poor compatibility between organic and inorganic composite materials.

Target-induced multiregion MNAzyme nanowires for ultrasensitive homogeneous detection of microRNAs.

A target-induced multiregion MNAzyme nanowire system is designed for the ultrasensitive and homogeneous detection of microRNAs (miRNAs). miRNA-21 and miRNA-375 are chosen as analytes, and a miRNA-induced primer exchange reaction (PER) is utilized to construct a long DNA strand with repetitive sequences. This innovative design enables the efficient anchoring of numerous MNAzymes. This unique architecture significantly boosts the effective local concentration of MNAzymes, thereby enhancing the sensitivity and efficiency of miRNA detection. Notably, the limit of detection (LOD) achieved with our target-induced multiregion MNAzyme nanowire approach is over an order of magnitude lower than most other MNAzyme-based methods, while the MNAzyme reaction time is reduced from several hours to 50 min. The method has demonstrated successful applications in quantitatively determining the expression levels of two miRNAs in cell lysates of MCF-7, HeLa and MCF-10 A cells, highlighting its potential for assaying miRNA biomarkers in clinical samples.

Platinum nanowires/MXene nanosheets/porous carbon ternary nanocomposites for in situ monitoring of dopamine released from neuronal cells.

Dopamine is an important neurotransmitter in the body and closely related to many neurodegenerative diseases. Therefore, the detection of dopamine is of great significance for the diagnosis and treatment of diseases, screening of drugs and unraveling of relevant pathogenic mechanisms. However, the low concentration of dopamine in the body and the complexity of the matrix make the accurate detection of dopamine challenging. Herein, an electrochemical sensor is constructed based on ternary nanocomposites consisting of one-dimensional Pt nanowires, two-dimensional MXene nanosheets, and three-dimensional porous carbon. The Pt nanowires exhibit excellent catalytic activity due to the abundant grain boundaries and highly undercoordinated atoms; MXene nanosheets not only facilitate the growth of Pt nanowires, but also enhance the electrical conductivity and hydrophilicity; and the porous carbon helps induce significant adsorption of dopamine on the electrode surface. In electrochemical tests, the ternary nanocomposite-based sensor achieves an ultra-sensitive detection of dopamine (S/N = 3) with a low limit of detection (LOD) of 28 nM, satisfactory selectivity and excellent stability. Furthermore, the sensor can be used for the detection of dopamine in serum and in situ monitoring of dopamine release from PC12 cells. Such a highly sensitive nanocomposite sensor can be exploited for in situ monitoring of important neurotransmitters at the cellular level, which is of great significance for related drug screening and mechanistic studies.

Exosomal membrane proteins analysis using a silicon nanowire field effect transistor biosensor.

Exosomes are of great significance in clinical diagnosis, due to their high homology with parental generation, which can reflect the pathophysiological status. However, the quantitative and classification detection of exosomes is still faced with the challenges of low sensitivity and complex operation. In this study, we develop an electrical and label-free method to directly detect exosomes with high sensitivity based on a Silicon nanowire field effect transistor biosensor (Si-NW Bio-FET). First, the impact of Debye length on Si-NW Bio-FET detection was investigated through simulation. The simulation results demonstrated that as the Debye length increased, the electrical response to Si-NW produced by charged particle at a certain distance from the surface of Si-NW was greater. A Si-NW Bio-FET modified with specific antibody CD81 on the nanowire was fabricated then used for detection of cell line-derived exosomes, which achieved a low limit of detection (LOD) of 1078 particles/mL in 0.01 × PBS. Furthermore, the Si-NW Bio-FETs modified with specific antibody CD9, CD81 and CD63 respectively, were employed to distinguish exosomes derived from human promyelocytic leukemia (HL-60) cell line in three different states (control group, lipopolysaccharide (LPS) inflammation group, and LPS + Romidepsin (FK228) drug treatment group), which was consistent with nano-flow cytometry. This study provides a highly sensitive method of directly quantifying exosomes without labeling, indicating its potential as a tool for disease surveillance and medication instruction.

Tapered cross-linked ZnO nanowire bundle arrays on three-dimensional graphene foam for highly sensitive electrochemical detection of levodopa.

It is crucial to accurately and rapidly monitor the levodopa (LD) concentration for accurate classification and treatment of dyskinesia in Parkinson's disease. In this paper, 3D graphene foam (GF) with a highly conductive network is obtained by chemical vapor deposition. 3D GF serves as the substrate for hydrothermal in situ growth of tapered cross-linked ZnO nanowire bundle arrays (ZnO NWBAs), enabling the development of a highly sensitive detection platform for LD. The formation mechanism of a tapered cross-linked ZnO nanowire bundle arrays on 3D GF is put forward. The integration of 3D GF and ZnO NWBAs can accelerate the electron transfer rate and increase the contact area with biomolecules, resulting in high electrochemical properties. The electrode composed of ZnO NWBAs on 3D GF exhibits significant sensitivity (1.66 µA·µM-1·cm-2) for LD detection in the concentration range 0-60 µM. The electrode is able to rapidly and specifically determine LD in mixed AA or UA solution. The selectivity mechanism of the electrode is also explained by the bandgap model. Furthermore, the successful detection of LD in serum demonstrates the practicality of the electrode and its great potential for clinical application.

Synergistic signal-amplification effect of silver nanowires and bifunctional monomers on molecularly imprinted electrochemical sensor for diuron analysis.

Molecularly imprinted polymers (MIP) have been widely owing to their specificity, however, their singular structure imposes limitations on their performance. Current enhancement methods, such as doping with inorganic nanomaterials or introducing various functional monomers, are limited and single, indicating that MIP performances require further advancement. In this work, a dual-modification approach that integrates both conductive inorganic nanomaterials and diverse bifunctional monomers was proposed to develop a multifunctional MIP-based electrochemical (MMIP-EC) sensor for diuron (DU) detection. The MMIP was synthesized through a one-step electrochemical copolymerization of silver nanowires (AgNWs), o-phenylenediamine (O-PD), and 3,4-ethylenedioxythiophene (EDOT). DU molecules could conduct fluent electron transfer within the MMIP layer through the interaction between anchored AgNWs and bifunctional monomers, and the abundant recognition sites and complementary cavity shapes ensured that the imprinted cavities exhibit high specificity. The current intensity amplified by the two modification strategies of MMIP (3.7 times) was significantly higher than the sum of their individual values (3.2 times), exerting a synergistic effect. Furthermore, the adsorption performance of the MMIP was characterized by examining the kinetics and isotherms of the adsorption process. Under optimal conditions, the MMIP-EC sensor exhibits a wide linear range (0.2 ng/mL to 10 µg/mL) for DU detection, with a low detection limit of 89 pg/mL and excellent selectivity (an imprinted factor of 10.4). In summary, the present study affords innovative perspectives for the fabrication of MIP-EC sensor with superior analytical performance.