Using the Photo-Piezoelectric Effect of AuPt@BaTiO3 Oxidase Mimetics for Colorimetric Detection of GSH in Serum.

Nanozymes possess major advantages in catalysis and biosensing compared with natural nanozymes. In this study, the AuPt@BaTiO3 bimetallic alloy Schottky junction is prepared to act as oxidase mimetics, and its photo-piezoelectric effect is investigated. The synergy between the photo-piezoelectric effect and the local surface plasmon resonance enhances the directional migration and separation of photogenerated electrons, as well as hot electrons induced by the AuPt bimetallic alloy. This synergy significantly improves the oxidase-like activity. A GSH colorimetric detection platform is developed based on this fading principle. Leveraging the photo-piezoelectric effect allows for highly sensitive detection with a low detection limit (0.225 µM) and reduces the detection time from 10 min to 3 min. The high recovery rate (ranging from 99.91% to 101.8%) in actual serum detection suggests promising potential for practical applications. The development of bimetallic alloy heterojunctions presents new opportunities for creating efficient nanozymes.

Plasmonic Array at the Liquid-Liquid Interface: A Dual-Mode Optical Sensing Platform for Multianalytes.

Analyte-triggered nanoparticle (NP) assemblies in bulk colloidal suspension have been extensively utilized in various optical sensors. Nevertheless, the assembling process is still limited by the slow diffusion dynamics of NPs and the low concentration of analytes in trace detections, which hinders further improvement of the sensitivity and repeatability of the sensors. In this work, by functionalizing the gold NPs with specific ligands, we constructed a dual-mode optical sensing platform for multianalytes based on the plasmonic NP array at the liquid-liquid interface. Through emulsification, the NP diffusion kinetics are boosted for several orders, and the NPs are condensed from the bulk aqueous phase to the liquid-liquid interface as a plasmonic array. The as-formed metasurface generates major reflectance and surface-enhanced Raman scattering changes in response to analytes, providing two optical sensing modes. As prototypes, cysteine and glucose are selected as the target molecules, achieving the limit of detection as 193 ± 2 and 297 ± 12 pM, respectively.