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Bioactive NAD+ mediated multiple biocatalytic pathways in metabolic networks. Refining the structure of NADH oxidase-like (NOX) mimics to efficiently replenish NAD+ has been promising but challenging in NAD+-dependent dehydrogenase electrochemical cascade biosensing. Herein, we discovered that PtOx structures, formed via lattice oxygen translocation from WO3 to Pt NPs at the interface, potentially activate and modulate the NOX-like functionality in Pt@WO3 nanosheets. Incorporating PtOx leads to a more positive valence of Pt species within Pt/PtOx@WO3−x, where the PtO2 species serve as preeminent reaction sites for NADH coordination, activation, and dehydrogenation. Consequently, such nanozymes display enhanced NOX-like activity towards NADH oxidation in comparison to Pt@WO3. Ultimately, the 650-Pt/PtOx@WO3−x nanozyme is employed in an electrochemical cascade biosensor for β-hydroxybutyrate (HB) detection, achieving a calculated detection limit of 25 μM. This study offers insights into PtOx activation in Pt-based NOX mimics and supports the future development of NAD+/NADH-dependent electrochemical biosensors. [ABSTRACT FROM AUTHOR]

One of the greatest challenges in the enhancement of the electrical properties of conductive mayenite [Ca24Al28O64]4+(4e−) (hereinafter C12A7:e−) is the design of a more suitable/simple synthesis strategy that can be employed to obtain the required properties such as excellent stable electrical conductivity, a high electron concentration, outstanding mobility, and an exceptionally large surface area. Therefore, to synthesize C12A7:e− in the metallic state, we proposed a facile, direct synthesis strategy based on an optimized sol–gel combustion method under a nitrogen gas environment using the low-cost precursors Ca(NO3)2·4H2O and Al(NO3)3·9H2O. Using this developed strategy, we successfully synthesized moderately conductive nanoscale C12A7:e− powder, but with unexpected carbon components (reduced graphene oxide (rGO) and/or graphene oxide (GO)). The synthesized C12A7:e− composite at room temperature has an electrical conductivity of about 21 S cm−1, a high electron concentration of approximately 1.5 × 1021 cm−3, and a maximum specific surface area of 265 m2 g−1. Probably, the synthesized rGO was coated on nanocage C12A7:e− particles. In general, the C12A7:e− electride is sensitive to the environment (especially to oxygen and moisture) and protected by an rGO coating on C12A7:e− particles, which also enhances the mobility and keeps the conductivity of C12A7:e− electride stable over a long period. Doped mayenite electride exhibits a conductivity that is strongly dependent on the substitution level. The conductivity of gallium-doped mayenite electride increases with the doping level and has a maximum value of 270 S cm−1, which for the first time has been reported for the stable C12A7:e− electride. In the case of Si-substituted calcium aluminate, the conductivity has a maximum value of 222 S cm−1 at room temperature. [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]