4-mercaptophenylboronic Acid Research Articles

Persistent chemiluminescence-based nanosensor for portable point-of-care testing of H2O2.

Anovel glow-type chemiluminescence (CL)-based nanosensing system was developed for sensitive and rapid point-of-care testing (POCT) of H2O2 in food. CuSe nanoparticles (CuSeNPs) have excellent peroxidase-like activity. After being modified with thiols of 4-mercaptophenylboronic acid (MBA) (CuSeNPs@MBA), luminol can be catalyzed to produce long-lasting CL in the presence of H2O2. The possible reason for the long-lasting glow-type CL behavior was explored. Under the optimized condition, H2O2 can be sensitively detected with improved repeatability. The limit of detection isas low as 0.30 μM. To meet the requirement of in situ and outside of laboratory detection, a 3D-printed portable device was designed which can eliminate the environmental interference to improve detection accuracy. The developed multifunctional platform also has the advantages of simple operation and low cost, suggesting its great potential for applications in food and agricultural fields.

AFB1-responsive mesoporous silica nanoparticles for AFB1 quantification based on aptamer-regulated release of SERS reporter

In this study, we propose a novel surface-enhanced Raman scattering (SERS) method for quantifying aflatoxin B1 (AFB1). This method relies on the target-triggered release of a SERS reporter from aptamer-sealed aminated mesoporous silica nanoparticles (MSNs). These MSNs were synthesized to accommodate 4-mercaptophenylboronic acid (4-MPBA) within their well-defined micropores, which were subsequently sealed with AFB1 aptamers. Upon specific binding of AFB1 to its aptamer, the conformational change in the aptamer is regulated by the presence of the target. Consequently, a positive linear relationship between the AFB1 concentration and the 4-MPBA SERS signal was observed. Under optimal conditions, the method exhibited a good linear relationship over the range of 0.1 to 5 ng/mL AFB1, with a limit of detection (LOD) of 0.03 ng/mL. This strategy was validated using wheat samples, yielding results comparable to high performance liquid chromatography-fluorescence detector (P > 0.05), confirming its reliability for detecting AFB1 in complex food matrices.

Preparation and exploration of anti-tumor activity of Poria cocos polysaccharide gold nanorods

With the continuous advancement of nanotechnology, the application of gold nanorods (AuNRs) functionalized with polysaccharides in the realm of cancer photothermal therapy is garnering increasing attention. To harness photothermal therapy for cancer treatment, FLP-MPBA-AuNRs were successfully synthesized in this study for the first time, utilizing Poria cocos polysaccharides (FLP), mercaptophenylboronic acid (MPBA), and gold nanorods (AuNRs). FLP-MPBA-AuNRs are a nanomaterial characterized by a unique rod-shaped structure, featuring a long diameter of 29.3 nm and a short diameter of 6.5 nm, which conferred exceptional photothermal stability and remarkable photothermal conversion efficiency. Under near-infrared light irradiation, FLP-MPBA-AuNRs elicited significant photothermal effects, effectively curtailing the proliferation of various cancer cells. Additionally, FLP-MPBA-AuNRs impeded cancer progression by inducing cell apoptosis and releasing reactive oxygen species (ROS). Furthermore, FLP-MPBA-AuNRs suppressed the metastasis and growth of cancer cells in zebrafish models. In summary, FLP-MPBA-AuNRs showcased immense potential in cancer therapy by inhibiting tumor cell growth through photothermal and photodynamic mechanisms.

Molecular Probe with Potential for Combined Boron Neutron Capture and Photothermal Antitumor Therapy.

Both boron neutron capture therapy (BNCT) and photothermal therapy (PTT) have been applied to tumor treatment in clinical. However, their therapeutic efficacy is limited. For BNCT, the agents not only exhibit poor targeting ability but also permit only a single irradiation session within a course due to significant radiation risks. In the context of PTT, despite enhanced selectivity, the limited photothermal effect fails to meet clinical demands. Hence, the imperative arises to combine these two therapies to enhance tumor-killing capabilities and improve the targeting of BNCT agents by leveraging the advantages of PTT agents. In this study, we synthesized a potential responsive agent by linking 4-mercaptophenylboronic acid (MPBA) and IR-780 dye that served as the agents for BNCT and PTT, respectively, which possesses the dual capabilities of photothermal effects and thermal neutron capture. Results from both in vitro and in vivo research demonstrated that IR780-MPBA effectively inhibits tumor growth through its photothermal effect with no significant toxicity. Furthermore, IR780-MPBA exhibited substantial accumulation in tumor tissues and superior tumor-targeting capabilities compared with MPBA, which demonstrated that IR780-MPBA possesses significant potential as a combined antitumor therapy of PTT and BNCT, presenting a promising approach for antitumor treatments.

Precise AIE-Based Ternary Co-Assembly for Saccharide Recognition and Classification.

Saccharides are involved in nearly all life processes. However, due to the complexity and diversity of saccharide structures, their selective recognition is one of the most challenging tasks. Distinct from conventional receptor designs that rely on delicate and complicated molecular structures, here a novel and precise ternary co-assembled strategy is reported for achieving saccharide recognition, which originates from a halogen ions-driven aggregation-induced emission module called p-Toluidine, N, N'-1-propen-1-yl-3-ylidene hydrochloride (PN-Tol). It exhibits ultra-strong self-assembly capability and specifically binds to 4-mercaptophenylboronic acid (MPBA), forming highly ordered co-assemblies. Subsequent binding of various saccharides results in heterogeneous ternary assembly behaviors, generating cluster-like, spherical, and rod-like microstructures with well-defined crystalline patterns, accompanied by significant enhancement of fluorescence. Owing to the excellent expandability of the PN module, an array sensor is constructed that enables easy classification of diverse saccharides, including epimer and optical isomers. This strategy demonstrates wide applicability and paves a new avenue for saccharide recognition, analysis, and sequencing.

Colorimetric detection of sitagliptin and moxifloxacin using AgNPs modified by 4-mercaptophenylbronic acid

Nowadays, considering the vital role of drugs, identifying and diagnosing them with simple and cost-effective methods and materials is very important. This study explores a colorimetric approach using silver nanoparticles (AgNPs) modified with 4-mercaptophenylboronic acid (MPBA) as a rapid and economical sensor for detecting Sitagliptin (Sit) and Moxifloxacin (Moxi) drugs. The MPBA-AgNPs sensor was synthesized via chemical synthesis of AgNPs followed by surface modification by MPBA. The effect of different parameters on the responsiveness of the MPBA-AgNPs sensor was investigated. The surface morphology, chemical structure, and size of the MPBA-AgNPs sensor in different conditions were examined by FE-SEM, FT-IR, DLS, and TEM analysis. Finally, the results of various investigations showed that the surface of AgNPs successfully modified by MPBA and MPBA-AgNPs as a colorimetric sensor for the detection of Sit and Moxi drugs has excellent detection limits of 16.63 and 0.27 µM. The recovery of the experiment in real samples was obtained in the range of 92.37–105.44 %.

A double boronic acid affinity "sandwich" SERS biosensor based on magnetic boronic acid controllable-oriented imprinting for high-affinity biomimetic specific recognition and rapid detection of target glycoproteins.

Transferrin (TRF), recognized as a glycoprotein clinical biomarker and therapeutic target, has its concentration applicable for disease diagnosis and treatment monitoring. Consequently, this study developed boronic acid affinity magnetic surface molecularly imprinted polymers (B-MMIPs) with pH-responsitivity as the "capture probe" for TRF, which have high affinity similar to antibodies, with a dissociation constant of (3.82 ± 0.24) × 10-8M, showing 7 times of reusability. The self-copolymerized imprinted layer synthesized with dopamine (DA) and 3-Aminophenylboronic acid (APBA) as double monomers avoided nonspecific binding sites and produced excellent adsorption properties. Taking the gold nanostar (AuNS) with a branch tip "hot spot" structure as the core, the silver-coated AuNS functionalized with the biorecognition element 4-mercaptophenylboronic acid (MPBA) was employed as a surface-enhanced Raman scattering (SERS) nanotag (AuNS@Ag-MPBA) to label TRF, thereby constructing a double boronic acid affinity "sandwich" SERS biosensor (B-MMIPs-TRF-SERS nanotag) for the highly sensitive detection of TRF. The SERS biosensor exhibited a detection limit for TRF of 0.004ng/mL, and its application to spiked serum samples confirmed its reliability and feasibility, demonstrating significant potential for clinical TRF detection. Moreover, the SERS biosensor designed in this study offers advantages in stability, detection speed (40min), and cost efficiency. The portable Raman instrument for SERS detection fulfills the requirements for point-of-care testing.

Simple and sensitive galactose monitoring based on capillary SERS sensor.

Galactosemia, a severe genetic metabolic disorder, results from the absence of galactose-degrading enzymes, leading to harmful galactose accumulation. In this study, we introduce a novel capillary-based surface-enhanced Raman spectroscopy (SERS) sensor for convenient and sensitive galactose detection. The developed sensor enhances SERS signals by introducing gold nanoparticles (Au NPs) onto the surface of silver nanoshells (Ag NSs) within a capillary, creating Ag NSs with Au NPs as satellites. Utilizing 4-mercaptophenylboronic acid (4-MPBA) as a Raman reporter molecule, the detection method relies on the conversion of 4-MPBA to 4-mercaptophenol (4-MPhOH) driven by hydrogen peroxide (H2O2) generated during galactose oxidation by galactose oxidase (GOx). A new SERS signal was observed, which was generated by H2O2 produced when galactose and GOx reacted. Our strategy yielded a quantitative change in the SERS signal, specifically in the band intensity ratio of 998 to 1076 cm-1 (I998/I1076) as the galactose concentration increased. Our capillary-based SERS biosensor provides a promising platform for early galactosemia diagnosis.

Plasmon-driven substitution of 4–mercaptophenylboronic acid to 4-nitrothiophenol monitored by surface-enhanced Raman spectroscopy

Plasmon-driven reactions on plasmonic nanoparticles (NPs) occur under significantly different conditions from those of classical organic synthesis and provide a promising pathway for enhancing the efficiency of various chemical processes. However, these reactions can also have undesirable effects, such as 4-mercaptophenylboronic acid (MPBA) deboronation. MPBA chemisorbs well to Ag NPs through its thiol group and can subsequently bind to diols, enabling the detection of various biological structures by surface-enhanced Raman scattering (SERS), but not upon its deboronation. To avoid this reaction, we investigated the experimental conditions of MPBA deboronation on Ag NPs by SERS. Our results showed that the level of deboronation strongly depends on both the morphology of the system and the excitation laser wavelength and power. In addition, we detected not only the expected products, namely thiophenol and biphenyl-4,4-dithiol, but also 4-nitrothiophenol (NTP). The crucial reagent for NTP formation was an oxidation product of hydroxylamine hydrochloride, the reduction agent used in Ag NP synthesis. Ultimately, this reaction was replicated by adding NaNO2 to the system, and its progress was monitored as a function of the laser power, thereby identifying a new reaction of plasmon-driven −B(OH)2 substitution for –NO2.

SERS-Based Microneedle Biosensor for In Situ and Sensitive Detection of Tyrosinase.

Tyrosinase (TYR) emerges as a key enzyme that exerts a regulatory influence on the synthesis of melanin, thereby assuming the role of a critical biomarker for the detection of melanoma. Detecting the authentic concentration of TYR in the skin remains a primary challenge. Distinguished from ex vivo detection methods, this study introduces a novel sensor platform that integrates a microneedle (MN) biosensor with surface-enhanced Raman spectroscopy (SERS) technology for the in situ detection of TYR in human skin. The platform utilized dopamine (DA)-functionalized gold nanoparticles (Au NPs) as the capturing substrate and 4-mercaptophenylboronic acid (4-MPBA)-modified silver nanoparticles (Ag NPs) acting as the SERS probe. Here, the Au NPs were functionalized with mercaptosuccinic acid (MSA) for DA capture. In the presence of TYR, DA immobilized on the MN is preferentially oxidized to dopamine quinone (DQ), a process that results in a decreased density of SERS probes on the platform. TYR concentration was detected through variations in the signal intensity emitted by the phenylboronic acid. The detection system was able to evaluate TYR concentrations within a linear range of 0.05 U/mL to 200 U/mL and showed robust anti-interference capabilities. The proposed platform, integrating MN-based in situ sensing, SERS technology, and TYR responsiveness, holds significant importance for diagnosing cutaneous melanoma.

Gold Nanoparticles in Porous Silicon Nanotubes for Glucose Detection

Silicon nanotubes (Si NTs) have a unique structure among the silicon nanostructure family, which is useful for diverse applications ranging from therapeutics to lithium storage/recycling. Their well-defined structure and high surface area make them ideal for sensing applications. In this work, we demonstrate the formation of Au nanoparticles (NPs) functionalized with 4-Mercaptophenylboronic acid (MPBA) on porous Si NTs (pSi NTs) fabricated using ZnO nanowires as a template. The system was characterized, and the proposed structure was confirmed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Varying glucose concentrations in phosphate-buffered saline (PBS) (0.5–80 mM) were introduced to the Si NT nanocomposite system. The glucose is detectable at low concentrations utilizing surface-enhanced Raman spectroscopy (SERS), which shows a concentration-dependent peak shift in the benzene ring breathing mode (~1071 cm−1) of MPBA. Complementing these measurements are simulations of the Raman hot spots associated with plasmonic enhancement of the Au NPs using COMSOL. This biocompatible system is envisioned to have applications in nanomedicine and microfluidic devices for real-time, non-invasive glucose sensing.

Forward-predictive SERS-based chemical taxonomy for untargeted structural elucidation of epimeric cerebrosides

Achieving untargeted chemical identification, isomeric differentiation, and quantification is critical to most scientific and technological problems but remains challenging. Here, we demonstrate an integrated SERS-based chemical taxonomy machine learning framework for untargeted structural elucidation of 11 epimeric cerebrosides, attaining >90% accuracy and robust single epimer and multiplex quantification with <10% errors. First, we utilize 4-mercaptophenylboronic acid to selectively capture the epimers at molecular sites of isomerism to form epimer-specific SERS fingerprints. Corroborating with in-silico experiments, we establish five spectral features, each corresponding to a structural characteristic: (1) presence/absence of epimers, (2) monosaccharide/cerebroside, (3) saturated/unsaturated cerebroside, (4) glucosyl/galactosyl, and (5) GlcCer or GalCer’s carbon chain lengths. Leveraging these insights, we create a fully generalizable framework to identify and quantify cerebrosides at concentrations between 10−4 to 10−10 M and achieve multiplex quantification of binary mixtures containing biomarkers GlcCer24:1, and GalCer24:1 using their untrained spectra in the models.

The Use of Conjugated Gold Nanorods with Reduced Toxicity in Photothermal Therapy for MRSA

AbstractMethicillin‐resistant Staphylococcus aureus (MRSA) is one of the deadliest pathogenic bacteria. Using photothermal therapy (PTT) to eradicate MRSA bacteria easily and effectively, it has directed this bacterium to be destroyed. Gold nanorods (AuNRs), which are nanoparticles that provide PPT, were synthesized and removed from the CTAB molecule reduce the toxic effect caused by CTAB. Subsequently, mercaptophenylboronic acid (MFBA) coated AuNRs were synthesized and used in photothermal therapy to develop a targeting agent to selectively eliminate MRSA. A decrease in cytotoxic effect of CTAB@AuNRs after conjugation with MFBA was also demonstrated by the MTS cell viability test. We found that at the end of 48 hours and 72 hours of interaction, IC50 values of MFBA@ AuNR increased by approximately 50 % compared to CTAB@AuNR. Also, it shows that the cytotoxicity of AuNRs conjugated with MFBA was reduced. Herein, photothermal efficiency was achieved with MFBA@AuNRs targeting MRSA. The purpose of using and modifying gold nanorods is to reduce the toxicity of AuNRs and to examine their efficacy on resistant pathogenic bacteria strains by taking advantage of photothermal therapy properties.

2D Film-Like Magnetic SERS Tag with Enhanced Capture and Detection Abilities for Immunochromatographic Diagnosis of Multiple Bacteria.

Here, a multiplex surface-enhanced Raman scattering (SERS)-immunochromatography (ICA) platform is presented using a graphene oxide (GO)-based film-like magnetic tag (GFe-DAu-D/M) that effectively captures and detects multiple bacteria in complex specimens. The 2D GFe-DAu-D/M tag with universal bacterial capture ability is fabricated through the layer-by-layer assembly of one layer of small Fe3O4 nanoparticles (NPs) and two layers of 30nm AuNPs with a 0.5nm built-in nanogap on monolayer GO nanosheets followed by co-modification with 4-mercaptophenylboronic acid (MPBA) and 5,5'-dithiobis-(2-nitrobenzoic acid).The GFe-DAu-D/M enabled the rapid enrichment of multiple bacteria by MPBA and quantitative analysis of target bacteria on test lines by specific antibodies, thus achieving multiple signal amplification of magnetic enrichment effect and multilayer dense hotspots and eliminating matrix interference in real-world applications. The developed technology can directly and simultaneously diagnose three major pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhimurium) with detection limits down to the level of 10cellsmL-1. The good performance of the proposed method in the detection of real urinary tract infection specimens is also demonstrated, suggesting the great potential of the GFe-DAu-D/M-ICA platform for the highly sensitive monitoring of bacterial infections or contamination.

Continuous in-vitro physiological glucose sensing for co-cultured 3D tumour spheroids using SERS based nano particle sensors (SERS-gNPS)

Evaluation of glucose in cancerous tumours acts as a hall mark for cancer progression and thus serves as a major interest in these days. Here, we have developed a biocompatible, surface enhanced Raman spectroscopy-based glucose Nano Particle Sensor (SERS-gNPS) to measure glucose dynamically in 3D Co-cultured Colon Cancer Tumour Spheroids (3D-CCTS). 3D-CCTS were produced using polydimethylsiloxane (PDMS) based µ-well array chip. SERS-gNPS was fabricated by conjugating 4-Mercaptophenylboronic acid (4-MPBA) to 50 nm silver nanoparticles (AgNP) and used under confocal Raman spectroscopy to measure glucose. The calibration curve shows direct relationship between Raman peak intensity at 1078 cm-1 with increasing glucose levels. The sensor has a limit of detection of 0.1 mM and found to be linear in the physiological range (1 mM – 10 mM) of glucose with an average standard deviation of ± 5%. SERS-gNPS was applied for continuous glucose measurement in an in-vitro 3D-CCTS and 3D Mono-cultured fibroblast Spheroids (3D-MS). The results revealed that the 3D-CCTS have more prominent glucose gradient (∼1 mM) as compared to 3D-MS (∼0.4 mM) from core to peripheral regions at 3 days to 5 days of culture. SERS-gNPS provides a platform for accurate and real-time measurement of glucose, and offers an enhanced understanding of glucose distribution in the tumour spheroids.

Sulfhydryl-mediated etching suppression of gold nanostars for rapid and sensitive detection of bacterial pathogens

Human infectious diseases caused by bacterial pathogens, such as meningitis and pyaemia, threaten the public health worldwide due to their acute onset and high mortality. Sensitive and rapid detection of bacterial pathogens is urgent for the treatment of infectious diseases clinically. However, current techniques are generally time-consuming and require large-scale equipment. Plasmonic nanosensors built on metallic nanomaterials have emerged as excellent tools for biomedical diagnostics. Herein, we report an etching suppression strategy for the sensitive and rapid detection of bacterial pathogens through gold nanostars. Sulfhydryl-containing ligands suppress the iodide-mediated surface etching of gold nanostars, depending on the type, concentration, and size of sulfhydryl-containing ligands. Using mercaptophenylboronic acid (MBA) and Pseudomonas aeruginosa (P. aeruginosa)-specific aptamer as multifunctional ligands, we specifically identify bacterial pathogens through sulfhydryl-mediated etching suppression with a linear detection range from 10 to 106 CFU/mL and a limit of detection of 2 CFU/mL. This etching suppression-based strategy enables the detection of Neisseria meningitidis in the cerebrospinal fluid and P. aeruginosa in the serum within 15 min, showing great potential as a point-of-care platform for clinical diagnosis.

Silver-coated hollow fiber surface plasmon resonance sensor for glucose detection with enhanced limit of detection.

A fiber-optic surface plasmon resonance (SPR) biosensor based on a silver-coated hollow fiber (HF) structure for glucose detection is presented. The sensor surface was immobilized with 4-mercaptophenylboronic acid (PMBA) acting as a glucose recognition monolayer. Then, gold nanoparticles (AuNPs) modified with 2-aminoethanethiol (2-AET) and PMBA were introduced onto the sensor surface after glucose was captured to enhance the wavelength shift of the SPR phenomenon excited by the light transmitted in the wall of the HF sensor. Instead of the conventional one-step sensitization pretreatment commonly used in the deposition process of silver films for fiber-optic SPR sensors, a sensitization-activation two-step activation method was adopted in the fabrication of the proposed sensor. Experiments for glucose detection were performed on the fabricated sensors in the concentration range of 1 nM-1 mM. Results showed that the sensor fabricated by the two-step activation method has a much larger shift of resonance wavelength than the sensor fabricated using the one-step sensitization method. The resonance wavelength shift was found to be linear to the logarithm of the concentration in the range of 1 nM-1 mM. The sensor achieved a limit of detection (LOD) of as low as 1 nM, which is at least an order of magnitude lower than that of other fiber-optic sensors for glucose detection reported previously. The presented HF glucose sensor has the potential for biosensing applications and provides a large reference value in the study of optical fiber SPR sensors for biosensing.

Phenylboronic acid modification-based novel dumbbell-shaped Au-Ag nanorod SERS substrates for ultrasensitive detection of SO42.

Based on the coordination principle of Lewis acids, a 4-mercaptophenylboronic acid (4-MPBA)-modified novel dumbbell-shaped Au-Ag nanorod (4-MPBA@DS Au-AgNR) substrate was developed, which could be combined with the surface-enhanced Raman scattering (SERS) technique to detect SO42- with high sensitivity and specificity. DS Au-AgNRs synthesized in this study with a dumbbell-shaped structure were verified by finite-difference time domain (FDTD) simulation to be capable of stimulating strong localized electromagnetic enhancement (EM) at nano-edge and gap, generating a large number of "hot spots" exhibiting excellent SERS performance. The 4-MPBA modified on its surface could specifically recognize SO42-, producing a change in the spectral peak at 1382 cm-1, thus realizing highly sensitive and specific sensing of SO42-. Under optimized conditions, this SERS sensor responded rapidly to SO42- within 2 minutes and demonstrated outstanding specificity. Calculation of the ratio of the characteristic peaks at 1382 and 1070 cm-1 (I1382/I1070) enabled the quantitative detection of SO42- in the range of 1 × 10-8-1 × 10-3 M, and the detection threshold was as low as 1 nM, which was superior to those of similar detection methods. Importantly, the utility and reliability of this SERS substrate for the determination of SO42- in actual samples were evaluated using ion chromatography as the gold standard, and there was no significant difference between the two protocols (P > 0.05), and the RSD was less than 6% with a satisfactory recovery rate (97.6-102.3%). Therefore, the present protocol has the advantages of simplicity and rapidity, high sensitivity, specificity, stability, and practicability in the determination of SO42- in aqueous solution, providing a reliable solution for tracing SO42- in the fields of food safety and environmental testing.

Thiol ligand-mediated exfoliation of bulk sulfur to nanosheets and nanodots: applications in antibacterial activity.

Reducing bulk materials to layers or dots results in profound alterations in their physiochemical and optoelectronic properties, leading to a wide array of applications, spanning from device manufacturing to biomedicine. In this regard, the preparation of sulfur nanomaterials has garnered significant attention due to their low toxicity. Traditional methods for sulfur nanomaterial synthesis often involve harsh reaction conditions, leaving a gap for convenient approaches to create nanomaterials, such as nanosheets (NSs) and nanodots (NDs). Herein, the mechanical exfoliation of bulk sulfur using a surfactant thiol ligand with probe sonication is reported, making a unique contribution to existing methods. In the reported method, the thiol group binds to sulfur surfaces, facilitating exfoliation and stabilization, while the hydrophilic ends provide functional groups for exfoliated nanomaterials. Exfoliation can yield either nanosheets or nanodots, depending on the thiol ligand and exfoliation time. This approach offers the opportunity to exfoliate bulk sulfur using bioactive thiol ligands. With this goal in mind, bulk sulfur was exfoliated with 4-mercaptophenylboronic acid (BA) to target Gram-positive bacteria. This innovative exfoliation strategy of bulk sulfur using thiol ligands holds immense promise for synthesizing functionalized sulfur nanomaterials with wide-ranging applications, particularly in biomedicine.

A mesothelin microsensor based on an embedded thionine electronic medium within an imprinted polymer on an acupuncture needle electrode.

An electrochemical microsensor for mesothelin (MSLN) based on an acupuncture needle (AN) was constructed in this work. To prepare the microsensor, MSLN was self-assembled on 4-mercaptophenylboronic acid (4-MPBA) by an interaction force between the external cis-diol and phenylboronic acid. This was followed by the gradual electropolymerization of thionine (TH) and eriochrome black T (EBT) around the anchored protein. The thickness of the surface imprinted layers influenced the sensing performance and needed to be smaller than the height of the anchored protein. The polymerized EBT was not electrically active, but the polymerized TH provided a significant electrochemical signal. Therefore, electron transfer smoothly proceeded through the eluted nanocavities. The imprinted nanocavities were highly selective toward MSLN, and the rebinding of insulating proteins reduced the electrochemical signal of the embedded pTH. The functionalized interface was characterized by SEM and electrochemical methods, and the preparation conditions were studied. After optimization, the sensor showed a linear response in the range of 0.1 to 1000 ng mL-1 with a detection limit of 10 pg mL-1, indicating good performance compared with other reported methods. This microsensor also showed high sensitivity and stability, which can be attributed to the fine complementation of the imprinted organic nanocavities. The sensitivity of this sensor was related to the nanocavities used for electron transport around the AuNPs. In the future, microsensors that can directly provide electrochemical signals are expected to play important roles especially on AN matrices.