Recent Prospects of Carbonaceous Nanomaterials-Based Laccase Biosensor for Electrochemical Detection of Phenolic Compounds.

Phenolic compounds (PhCs) are ubiquitously distributed phytochemicals found in many plants, body fluids, food items, medicines, pesticides, dyes, etc. Many PhCs are priority pollutants that are highly toxic, teratogenic, and carcinogenic. Some of these are present in body fluids and affect metabolism, while others possess numerous bioactive properties such as retaining antioxidant and antimicrobial activity in plants and food products.

Graphitic Carbon Nitride-Wrapped Metal-free PoPD-Based Biosensor for Xanthine Detection.

A metal-free, enzymatic biosensor was developed using graphitic carbon nitride (g-CN)-wrapped poly--phenylenediamine (PPD) for the determination of xanthine (Xn). Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction confirmed the successful formation of the PPD, g-CN nanosheets and PoPD@g-CN nanocomposite. Furthermore, the electrochemical behavior of the biosensor was characterized by cyclic voltammetry and electrochemical impedance spectroscopy.

Development of conducting cellulose paper for electrochemical sensing of procalcitonin.

An electrochemical paper-based sensor was developed for the detection of bacterial infection (BI)-specific biomarker procalcitonin (PCT). Reduced graphene oxide-gold nanoparticles (rGO-AuNP) and poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were synthesized and were fabricated to a disposable, portable, and inexpensive cellulose fiber paper (CFP) substrate. rGO-AuNP-PEDOT:PSS nanocomposite-modified conductive paper-based biosensing platform was efficaciously fabricated by a constant and simple coating procedure.

Highly Sensitive Enzymatic Biosensor Based on Polyaniline-Wrapped Titanium Dioxide Nanohybrid for Fish Freshness Detection.

Herein, we envisage the fabrication of a highly sensitive enzymatic electrochemical biosensor for selective detection of xanthine (Xn) using xanthine oxidase (XOs) immobilized polyaniline-wrapped titanium dioxide (PANI@TiO) nanohybrid as a sensing platform. The PANI@TiO nanohybrid was synthesized via chemical polymerization using ammonium per sulfate as an oxidant. Various microscopic, spectroscopic, and electrochemical techniques have been utilized to confirm the electrophoretic deposition of the PANI and PANI@TiO nanohybrids on to indium tin oxide (ITO) coated glass substrate.

Highly sensitive electrochemical detection of cancer biomarker based on anti-EpCAM conjugated molybdenum disulfide grafted reduced graphene oxide nanohybrid.

An ultrasensitive, electrochemical biosensor has been fabricated by utilizing molybdenum disulfide (MoS) grafted reduced graphene oxide (MoS@rGO) nanohybrid as a sensing platform. Biomolecular-assisted synthetic method was adopted to synthesize MoS@rGO nanohybrid, where L-cys was used to reduce GO. The MoS@rGO nanohybrid exhibits improved electrochemical performance when it has been electrophoretically deposited onto the indium tin oxide (ITO) coated glass substrate.

Electrochemical biosensor for the epithelial cancer biomarker EpCAM based on reduced graphene oxide modified with nanostructured titanium dioxide.

An electrochemical immunosensor has been fabricated for the early determination of epithelial cell adhesion molecules (EpCAM, tumor biomarker) antigen using reduced graphene oxide (rGO) modified with nanostructured titanium dioxide (TiO). The hydrothermally synthesized rGO@TiO nanocomposite has been electrophoretically deposited on indium tin oxide (ITO) coated glass substrate, and the deposition was confirmed using various spectroscopic, microscopic, and electrochemical techniques. The fabricated rGO@TiO/ITO electrode shows improved electron transfer kinetics with an electron transfer rate constant of 1.

Nanomaterial-Modified Conducting Paper: Fabrication, Properties, and Emerging Biomedical Applications.

The emerging demand for wearable, lightweight portable devices has led to the development of new materials for flexible electronics using non-rigid substrates. In this context, nanomaterial-modified conducting paper (CP) represents a new concept that utilizes paper as a functional part in various devices. Paper has drawn significant interest among the research community because it is ubiquitous, cheap, and environmentally friendly.

An impedimetric biosensor based on electrophoretically assembled ZnO nanorods and carboxylated graphene nanoflakes on an indium tin oxide electrode for detection of the DNA of Escherichia coli O157:H7.

Aminopropyltrimethoxysilane (APTMS)-functionalized zinc oxide (ZnO) nanorods and carboxylated graphene nanoflakes (c-GNF) were used in a composite that was electrophoretically deposited on an indium tin oxide (ITO) coated glass substrate. The modified ITO electrodes were characterized using various microscopic and spectroscopic techniques which confirm the deposition of the APTMS-ZnO/c-GNF composite. The electrodes have been used for the covalent immobilization of an Escherichia coli O157:H7 (E.

Highly efficient Polyaniline-MoS hybrid nanostructures based biosensor for cancer biomarker detection.

In this work, polyaniline nanospindles have been synthesized using iron oxide as sacrificial template. These nanospindles were utilized for the fabrication of PANI-MoS nanoflower architectures via hydrothermal route. The electrostatic interaction between PANI and MoS improves the conductivity and provides more direct paths for charge transportation.

Electrochemical genosensor based on template assisted synthesized polyaniline nanotubes for chronic myelogenous leukemia detection.

This work reports a facile approach to synthesize polyaniline nanotubes (PANI-NT) by using manganese oxide as sacrificial templates. This template assisted polyaniline nanotubes (t-PANI-NT) were utilized as electrode material after deposition onto the indium tin oxide (ITO) coated glass substrates by using the electrophoretic technique. The structural, morphological and electrochemical characterizations of the t-PANI-NT show relatively better results compared to chemically synthesized PANI-NT (c-PANI-NT).

Controlled deposition of functionalized silica coated zinc oxide nano-assemblies at the air/water interface for blood cancer detection.

We report results of the studies relating to controlled deposition of the amino-functionalized silica-coated zinc oxide (Am-Si@ZnO) nano-assemblies onto an indium tin oxide (ITO) coated glass substrate using Langmuir-Blodgett (LB) technique. The monolayers have been deposited by transferring the spread solution of Am-Si@ZnO stearic acid prepared in chloroform at the air-water interface, at optimized pressure (16 mN/m), concentration (10 mg/ml) and temperature (23 °C). The high-resolution transmission electron microscopic studies of the Am-Si@ZnO nanocomposite reveal that the nanoparticles have a microscopic structure comprising of hexagonal assemblies of ZnO with typical dimensions of 30 nm.

Gold nanoparticle decorated graphene sheet-polypyrrole based nanocomposite: its synthesis, characterization and genosensing application.

We report herein the synthesis of gold nanoparticle (GNP) decorated-graphene sheets (GO-GNPs) using the template of graphene oxide (GO) by a one-pot solution-based method. A polypyrrole-GO decorated GNP nanocomposite (GO-GNP/PPY) has been electropolymerized using a potentiodynamic method on an indium tin oxide (ITO) coated glass substrate. The as-synthesized nanocomposites are characterized by transmission electron microscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared and Raman spectroscopy.

Nanostructuring of hierarchical 3D cystine flowers for high-performance electrochemical immunosensor.

Here, we report a simple and reproducible method for large scale fabrication of novel flower and palm-leaf like 3D cystine microstructures (CMs) with high uniformity having a size of 50 µm and 10 µm respectively, through a facile aqueous solution route as a function of pH and concentration. In a proof-of-concept study, the 3D CMs have been further explored to fabricate a label-free high-performance electrochemical immunosensor by immobilizing monoclonal antibodies. Electrochemical methods were employed to study the stepwise modification of the system and the electronic transduction for the detection.

Cationic poly(lactic-co-glycolic acid) iron oxide microspheres for nucleic acid detection.

Herein, we envisage the possibility of preparing stable cationic poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating the iron oxide nanoparticles (IONPs; 8-12 nm). The IONPs are incorporated into PLGA in organic phase followed by microsphere formation and chitosan coating in aqueous medium via nano-emulsion technique. The average size of the microspheres, as determined by dynamic light scattering are about 310 nm, while the zeta potential for the composite remains near 35 mV at pH 4.

Chitosan encapsulated quantum dots platform for leukemia detection.

We report results of the studies relating to electrophoretic deposition of nanostructured composite of chitosan (CS)-cadmium-telluride quantum dots (CdTe-QDs) onto indium-tin-oxide coated glass substrate. The high resolution transmission electron microscopic studies of the nanocomposite reveal molecular level coating of the CdTe-QDs with CS molecules in the colloidal dispersion medium. This novel composite platform has been explored to fabricate an electrochemical DNA biosensor for detection of chronic myelogenous leukemia (CML) by immobilizing amine terminated oligonucleotide probe sequence containing 22 base pairs, identified from BCR-ABL fusion gene.

Microstructured cystine dendrites-based impedimetric sensor for nucleic acid detection.

We report results of the studies relating to the fabrication and characterization of novel biosensing electrode by covalent immobilization of DNA onto microstructural cystine (Cys) prepared by acoustic cavitation method. The TEM investigations of these structures reveal transformation of microstructured Cys from nanorods to dendritic structure under optimum conditions. The Cys dendrites (denCys) have been investigated by XRD, FT-IR, and SEM studies.