Electrocatalytic performance of silica nanoparticles on graphene oxide sheets for hydrogen peroxide sensing

Recent Advances in Electrochemical Sensing of Hydrogen Peroxide (H2O2) Released from Cancer Cells

Cancer is by far the most common cause of death worldwide. There are more than 200 types of cancer known hitherto depending upon the origin and type. Early diagnosis of cancer provides better disease prognosis and the best chance for a cure. This fact prompts world-leading scientists and clinicians to develop techniques for the early detection of cancer. Thus, less morbidity and lower mortality rates are envisioned. The latest advancements in the diagnosis of cancer utilizing nanotechnology have manifested encouraging results. Cancerous cells are well known for their substantial amounts of hydrogen peroxide (H₂O₂). The common methods for the detection of H₂O₂ include colorimetry, titration, chromatography, spectrophotometry, fluorimetry, and chemiluminescence. These methods commonly lack selectivity, sensitivity, and reproducibility and have prolonged analytical time. New biosensors are reported to circumvent these obstacles. The production of detectable amounts of H₂O₂ by cancerous cells has promoted the use of bio- and electrochemical sensors because of their high sensitivity, selectivity, robustness, and miniaturized point-of-care cancer diagnostics. Thus, this review will emphasize the principles, analytical parameters, advantages, and disadvantages of the latest electrochemical biosensors in the detection of H₂O₂. It will provide a summary of the latest technological advancements of biosensors based on potentiometric, impedimetric, amperometric, and voltammetric H₂O₂ detection. Moreover, it will critically describe the classification of biosensors based on the material, nature, conjugation, and carbon-nanocomposite electrodes for rapid and effective detection of H₂O₂, which can be useful in the early detection of cancerous cells.

Plant-derived silica nanoparticles and composites for biosensors, bioimaging, drug delivery and supercapacitors: a review

Silica nanoparticles have rapidly found applications in medicine, supercapacitors, batteries, optical fibers and concrete materials, because silica nanoparticles have tunable physical, chemical, optical and mechanical properties. In most applications, high-purity silica comes from synthetic organic precursors, yet this approach could be costly, polluting and non-biocompatible. Alternatively, natural silica sources from biomass are often cheap and abundant, yet they contain impurities. Silica can be extracted from corn cob, coffee husk, rice husk, sugarcane bagasse and wheat husk wastes, which are often disposed of in rivers, lands and ponds. These wastes can be used to prepare homogenous silica nanoparticles. Here we review properties, preparation and applications of silica nanoparticles. Preparation includes chemical and biomass methods. Applications include biosensors, bioimaging, drug delivery and supercapacitors. In particular, to fight the COVID-19 pandemic, recent research has shown that silver nanocluster/silica deposited on a mask reduces SARS-Cov-2 infectivity to zero.

Graphene-decorated silica stabilized stearic acid as a thermal energy storage material

Graphene-decorated silica stabilized stearic acid composites with interesting thermal energy storage behaviors.

Recent advances in graphene-based nanomaterials for fabricating electrochemical hydrogen peroxide sensors

Due to the large specific surface area, extraordinary mechanical flexibility, chemical stability, and superior electrical and thermal conductivities, graphene (G)-based materials have recently opened up an exciting field in the science and technology of two-dimensional (2D) nanomaterials with continuously growing academic and technological impetus. In the past several years, graphene-based materials have been well designed, synthesized, and investigated for sensing applications. In this review, we discuss the synthesis and application of graphene-based 2D nanomaterials for the fabrication of hydrogen peroxide (H₂O₂) electrochemical sensors. In particular, graphene-based nanomaterials as immobilization matrix of heme proteins for the fabrication of enzymatic H₂O₂ electrochemical biosensors is first summarized. Then, the application of graphene-based electrocatalysts (metal-free, noble-metals and non-noble metals) in constructing non-enzymatic H₂O₂ electrochemical sensors is discussed in detail. We hope that this review is helpful to push forward the advancement of this academic issue (189 references).

Graphene-based protein biomarker detection

An ability to detect and quantify protein molecules, harbingers of specific pathologies, potentially underpins both early disease diagnosis and an assessment of treatment efficacy. However, the specific detection of a particular protein biomarker in a complex environment is by no means an easy task and requires a progressive improvement in sensor technology. The high surface area, volume, electrical conductance, atomic level thickness and apparent biocompatibility of graphene makes it potentially an exceedingly powerful transducer of biorecognition events; the demands of its application in biosensing, and progress to date are reviewed herein.

rGO quantum dots/ZnO hybrid nanofibers fabricated using electrospun polymer templates and applications in drug screening involving an intracellular H2O2 sensor

Throughout the years, reported intracellular H₂O₂ sensors just focused on unrelated measurements of intracellular H₂O₂ generated from the stimulus of Cd²⁺, ascorbic acid (AA) etc., leading to difficulty in data interpretation. Here, a novel reduced graphene oxide quantum dots (rGO QDs)/ZnO hybrid nanofibers-based electrochemical biosensor for the detection of intracellular H₂O₂ released from cancer and normal cells under the stimuli of the corresponding anticancer drugs permits a quantitative study of the interaction between the target drug compound and the cancer cell, which is suitable for candidate drug screening. Nylon 6/6 nanofibers are used as robust templates for the facile fabrication of novel rGO QDs/ZnO hybrid nanofibers via electrospinning followed by a step hydrothermal growth method. The as-made sensor was applied to determine H₂O₂ released from a prostate cancer cell (PC-3) versus a noncancerous cell (BPH-1) under the stimuli of the corresponding anticancer drugs (apigenin, antisense CK2αetc.). The amount of H₂O₂ released from the PC-3 cancer cell is about (320 ± 12) amol per cell and about (210 ± 6) amol per cell for the BPH-1 noncancerous cell under the stimuli of specific therapy drug antisense CK2α. These results demonstrate that the rGO QDs/ZnO hybrid nanofibers-based electrochemical biosensor can efficiently detect the distinct amounts of H₂O₂ released from cancer and noncancer cells.

Quick synthesis of zeolitic imidazolate framework microflowers with enhanced supercapacitor and electrocatalytic performances

Novel zeolitic imidazolate framework-67 (ZIF-67) microflowers were synthesized by a quick and simple method without using any template or surfactant.

Electrochemical biosensors on platforms of graphene

In recent years, graphene, the two-dimensional closely packed honeycomb carbon lattice, has been attracting much attention in the field of electrochemistry due to its intrinsic properties and merits. Efforts to create novel graphene based electrochemical biosensors have led to the establishment of effective strategies for diverse bioassays, from simple molecules to complex biotargets. In this Feature Article, we provide an overview of electrochemical biosensing with graphene related materials, and discuss the role of graphene in different sensing protocols.

Delocalization of electronic states in graphene oxide stabilised mesoporous silica nanoparticles revealed using photoluminescence

Mesoporous silica aerogel obtained through a sol–gel process when surface treated with 2-D graphene oxide sheets reveals many fascinating features particularly, leading to multiple coordination complexes based on amide linkages.