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For the construction of halide perovskite-based photoelectrochemical (PEC) biosensors in aqueous solution, the balance between retaining the excellent photoelectric performances of the halide perovskite and the protective modification of the halide perovskite has always been a challenging problem. In this work, a simple and sensitive photoelectrochemical biosensor based on inorganic halide perovskite CsPbBr3 as the photoactive material for the detection of alkaline phosphatase (ALP) was reported. The substrate sodium thiophosphate (Na3SPO3) can be catalyzed by ALP to produce hydrogen sulfide (H2S), which can react with the lead site on the surface of the CsPbBr3 film to form lead sulfide (PbS), resulting in a stable heterostructure and enhanced photocurrent intensity. The possible mechanism of enhanced photocurrent response of CsPbBr3/PbS heterojunctions was studied in detail. This work paves a new way for applying halide perovskites in different biosensor designs. [ABSTRACT FROM AUTHOR]

A novel, highly stable, non-carbon support system for the oxygen reduction reaction (ORR) has been discovered in the form of nano-structured (NbxTi1−x)Ns (x = 0.25 and 0.5). Template-free, solid–solid separation synthetic approaches have been used for preparing these materials. The (NbxTi1−x)N materials have high specific surface area and better electronic conductivity than carbon-based supports. [ABSTRACT FROM AUTHOR]

Resistivity and powder X-ray diffraction measurements on Cs2Au2I6up to 320 kbar pressure show that the suppression of Au+/Au3+charge order above 55 kbar results in a non-metallic phase containing localised Au2+states that is irreversibly amorphised above 120 kbar, and a gradual metallisation observed above 175 kbar may result from decomposition within the amorphous material. [ABSTRACT FROM AUTHOR]

A simple and sensitive immunosensor for the detection of cancer biomarker prostate specific antigen (PSA) has been developed. Around the percolation threshold of the graphene film, the conductivity of the graphene film varies significantly with the surface adsorption of molecules, which can be used for the detection of proteins based on antibody–antigen binding. [ABSTRACT FROM AUTHOR]

A silica ring-based ratiometric fluorescence nanosensing and imaging platform was established for the quantification of miRNA-21 with carbon dots and nucleic-functionalized gold nanoparticles inside and outside the ring, respectively. In the presence of miRNA-21, on one hand, the fluorescence emission signal of the originally quenched 6-carboxyfluorescein (FAM), which was labeled on the nucleic acid molecules that modified on the gold nanoparticles, was re-emitted. On the other hand, the fluorescence intensity of the carbon dots inside the ring remained essentially unchanged, which served to eliminate background interference. The ring rather than the shell well maintained the fluorescence of the carbon dots. The ratio of the recovered fluorescence intensity of FAM to the fluorescence intensity of the carbon dots was linearly correlated with the logarithm of miRNA-21 concentration. The linear range of the probe for miRNA detection was more than 3 orders of magnitude, and the detection limit was as low as 2.5 aM. The feasibility of the method for clinical application was verified by the quantitative analysis of intracellular miRNA. [ABSTRACT FROM AUTHOR]

The rational design of nanozymes as new "antibiotics" for bacterial therapy is a promising area in healthcare. Herein, B-doped core–shell Fe@BC nanozymes functioned with peroxidase-like activity for bacterial inhibition were studied. Experimental and theoretical results show that the BCO2 site enables a much lower energy barrier than the BC2O site, with a positive correlation between the density and activity of BCO2. The enzyme-like and positively-charged properties of core–shell Fe@BC improve the production and utilization of ˙OH to efficiently kill bacteria. This study not only highlights a promising peroxidase mimic for hygiene management but also deepens the understanding of B-doped carbon nanozymes. [ABSTRACT FROM AUTHOR]

Proteins were proved to be type-independent templates for the biomineralization of iron ions into hematite mesocrystals with tunable structures and morphologies under hydrothemal conditions. Our finding could pave the way for the synthesis of mesocrystals with controlled stuctures and morphologies using templates of low-cost proteins. [ABSTRACT FROM AUTHOR]