Electrochemical Biosensor Based on Boron-Doped Diamond Electrodes with Modified Surfaces

Boron-doped diamond (BDD) thin films, as one kind of electrode materials, are superior to conventional carbon-based materials including carbon paste, porous carbon, glassy carbon (GC), carbon nanotubes in terms of high stability, wide potential window, low background current, and good biocompatibility. Electrochemical biosensor based on BDD electrodes have attracted extensive interests due to the superior properties of BDD electrodes and the merits of biosensors, such as specificity, sensitivity, and fast response. Electrochemical reactions perform at the interface between electrolyte solutions and the electrodes surfaces, so the surface structures and properties of the BDD electrodes are important for electrochemical detection. In this paper, the recent advances of BDD electrodes with different surfaces including nanostructured surface and chemically modified surface, for the construction of various electrochemical biosensors, were described

Template-free synthesis of mesoporous N-doped SrTiO3 perovskite with high visible-light-driven photocatalytic activity

An effective, template-free synthesis methodology has been developed for preparing mesoporous nitrogen-doped SrTiO3 (meso-STON) using glycine as both a nitrogen source and a mesopore creator. The N-doping, large surface area and developed porosity endow meso-STON with excellent activity in visible-light-responsive photodegradation of organic dyes

Recent applications of fluorescent nanodiamonds containing nitrogen-vacancy centers in biosensing

Fluorescent nanodiamonds (FNDs) with nitrogen-vacancy (NV) centers have been extensively studied in numerous fields because of their distinct magneto-optical properties. The NV center is a perfect candidate for a nanosensor because of its stable photoluminescence and manipulable spin state by microwave/magnetic field. Considering the controllable sizes (5–100 nm), abundant surface groups, and good biocompatibility, FNDs are valuable in biosensing to study the physiological activity at the cellular scale. This review summarizes the recent applications of FNDs in detecting physiological parameters (such as temperature, pH) as well as proteins, free radicals, viruses, etc. Highlights include the development of FND-based biosensors and the NV center transduction system that responds to signal changes or concentrations fluctuations of target species

Development and Application of an Electrochemical Sensor with 1,10-Phenanthroline-5,6-dione-Modified Electrode for the Detection of <i>Escherichia coli</i> in Water

The routine monitoring of bacterial populations is crucial for ensuring water quality and safeguarding public health. Thus, an electrochemical sensor based on a 1,10-phenanthroline-5,6-dione-modified electrode was developed and explored for the detection of E. coli. The modified electrode exhibited enhanced NADH oxidation ability at a low potential of 0.1 V, which effectively eliminated the interference from other redox compounds in bacteria. The sensitivity for NADH was 0.222 μA/μM, and the limit of detection was 0.0357 μM. Upon cell lysis, the intracellular NADH was released, and the concentration of E. coli was determined through establishing the relationship between the oxidation current signal and NADH concentration. The performance of the electrochemical sensor in the detection of NADH and E. coli suspensions was validated using the WST-8 colorimetric method. The blank recovery experiment in real water samples exhibited good accuracy, with recovery rates ranging from 89.12% to 93.26% and relative standard deviations of less than 10%. The proposed electrochemical sensor realized the detection of E. coli without the usage of biomarkers, which provides a promising approach for the broad-spectrum detection of microbial contents in complex water environments

Emerging applications of nanodiamonds in photocatalysis

As a fascinating nanocarbon photocatalytic material, nanodiamonds (NDs) have attracted more and more attention recently due to their high chemical stability, high carrier mobility, narrowing band gap, easy surface modification, and mass production. This review summarizes the latest progress related to elaborated construction of NDs and NDs-based nanocomposite, including microstructure regulation of pristine NDs, elemental doping and formation a heterojunction by coupled with another semiconductor. The construction and properties of each category of NDs-based material are reviewed on their structure, preparation methods, texture control, and photocatalytic performance. Photocatalytic applications of NDs-based nanomaterials for hydrogen evolution from water splitting, organic pollution degradation, CO2 reduction, N2 reduction, graphene oxide reduction, and the latest advances in photocatalytic reaction mechanism have been also systematically reviewed. Finally, the challenges and prospects of the photocatalytic application of NDs are also briefly analyzed