New Au/chitosan nanocomposite modified carbon paste sensor for voltammetric detection of nicotine

A profoundly touchy voltammetric sensor for detection of nicotine (NIC) in urine and tobacco specimens has been developed in light of the boosted electrochemical response of NIC at gold and chitosan nanocomposite modified carbon paste electrode (ACMCPE). Material characterization techniques Scanning Electron Microscope and Energy Dispersive X-ray (SEM & EDX) were utilized to describe the ACMCPE surface material. The impedance spectroscopy technique (EIS), cyclic voltammetry (CV), chronoamperometry (CA), and differential pulse voltammetry (DPV) were employed to explore the electrochemical sensing of NIC at ACMCPE. The created sensor exhibits an exceptional electrochemical sensitivity to NIC in a universal Britton-Robinson (B-R) buffer solution with a pH range of 2.0 to 8.0. The sensor shows a linear response over NIC concentration ranges of 4.0-320.0 µM, with the detection limit (LOD) of 7.6 µM. The prepared sensor has been shown to be exceptionally viable in detecting NIC with amazing selectivity and reproducibility. We suggest it as a trustworthy and useful electrochemical sensor for NIC location.

Nanotechnology-based approaches for effective detection of tumor markers: A comprehensive state-of-the-art review

As well-appreciated biomarkers, tumor markers have been spotlighted as reliable tools for predicting the behavior of different tumors and helping clinicians ascertain the type of molecular mechanism of tumorigenesis. The sensitivity and specificity of these markers have made them an object of even broader interest for sensitive detection and staging of various cancers. Enzyme-linked immunosorbent assay (ELISA), fluorescence-based, mass-based, and electrochemical-based detections are current techniques for sensing tumor markers. Although some of these techniques provide good selectivity, certain obstacles, including a low sample concentration or difficulty carrying out the measurement, limit their application. With the advent of nanotechnology, many studies have been carried out to synthesize and employ nanomaterials (NMs) in sensing techniques to determine these tumor markers at low concentrations. The fabrication, sensitivity, design, and multiplexing of sensing techniques have been uplifted due to the attractive features of NMs. Various NMs, such as magnetic and metal nanoparticles, up-conversion NPs, carbon nanotubes (CNTs), carbon-based NMs, quantum dots (QDs), and graphene-based nanosensors, hyperbranched polymers, optical nanosensors, piezoelectric biosensors, paper-based biosensors, microfluidic-based lab-on-chip sensors, and hybrid NMs have proven effective in detecting tumor markers with great sensitivity and selectivity. This review summarizes various categories of NMs for detecting these valuable markers, such as prostate-specific antigen (PSA), human carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), human epidermal growth factor receptor-2 (HER2), cancer antigen 125 (CA125), cancer antigen 15-3 (CA15-3, MUC1), and cancer antigen 19-9 (CA19-9), and highlights recent nanotechnology-based advancements in detection of these prognostic biomarkers.

Recent Trends in Electrochemical Sensors for Vital Biomedical Markers Using Hybrid Nanostructured Materials

This work provides a succinct insight into the recent developments in electrochemical quantification of vital biomedical markers using hybrid metallic composite nanostructures. After a brief introduction to the biomarkers, five types of crucial biomarkers, which require timely and periodical monitoring, are shortlisted, namely, cancer, cardiac, inflammatory, diabetic and renal biomarkers. This review emphasizes the usage and advantages of hybrid nanostructured materials as the recognition matrices toward the detection of vital biomarkers. Different transduction methods (fluorescence, electrophoresis, chemiluminescence, electrochemiluminescence, surface plasmon resonance, surface-enhanced Raman spectroscopy) reported for the biomarkers are discussed comprehensively to present an overview of the current research works. Recent advancements in the electrochemical (amperometric, voltammetric, and impedimetric) sensor systems constructed with metal nanoparticle-derived hybrid composite nanostructures toward the selective detection of chosen vital biomarkers are specifically analyzed. It describes the challenges involved and the strategies reported for the development of selective, sensitive, and disposable electrochemical biosensors with the details of fabrication, functionalization, and applications of hybrid metallic composite nanostructures.

Detection of four phenolic oestrogens by a novel electrochemical immunosensor based on a hexestrol monoclonal antibody

A novel HEX monoclonal antibody/MACA/nanogold electrochemical immunosensor was constructed to detect four phenolic oestrogens by a nanosized effect, layer by layer self-assembly and antigen–antibody specific immune technology.

Superoxide Anion Biosensor Based on Bionic-Enzyme Hyperbranched Polyester Particles

Self-assembly techniques have been demonstrated to be a useful approach to developing new functional nanomaterials. In this study, a novel method to fabricate a manganese phosphate self-assembly monolayer (SAM) on a hyperbranched polyester (HBPE-OH) nanoparticle surface is described. First, the second-generation aliphatic HBPE-OH was carboxy-terminated, phosphorylated, and then ionized with manganese by a three-step modification process. The final product of HBPE-AMPA-Mn2+ particles was obtained and characterised by FT-IR spectroscopy, 1H NMR spectroscopy, transmission electron microscopy (TEM), Zeta potential, and energy dispersive spectroscopy (EDS). Moreover, the HBPE-AMPA-Mn2+ particles were used to construct a novel biosensor for detection of superoxide anions (O2•−) released from HeLa cells. Results showed that the response currents of this biosensor were proportional to the O2•− concentration ranging from 0.79 to 16.6 μM, and provided an extremely low detection limit of 0.026 μM (S/N = 3). The results indicate that the particle-decorated electrode surface, which involved a hyperbranched structure and a surface self-assembly technology, proposed here will offer the ideal catalytic system for electrochemical enzymatic sensors.