In situ synthesis of chiral AuNCs with aggregation-induced emission using glutathione and ceria precursor nanosheets for glutathione biosensing

Abstract

In the present study, a mediator release test (MRT) strategy has been designed for the photoluminescent sensing of glutathione (GSH). On the basis of the redox reaction of GSH and cerium-based nanosheets (Ce(CO₃)₂ NSs), Ce³⁺ ions were released to act as a mediator for the photoluminescence emission of the Au–thiolate complexes through an aggregation-induced emission (AIE) process. Remarkably, AIE was also accompanied by high chirality for the in situ synthesis of AuNCs using Ce(CO₃)₂ NSs as a template and GSH as a releaser for oligomeric Au–thiolate complexes. Multiple characterization techniques, including high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), selected-area electron diffraction (SAED), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were employed to check the structure and morphology of the Ce(CO₃)₂ NSs as well as the successful in situ fabrication of the AuNCs. Using this new MRT strategy, an eco-friendly, selective, biocompatible and label-free AIE probe was established for the sensitive sensing of GSH with a limit of detection (LOD) of 1.02 μM. Moreover, this switch-on luminescent nanoplatform of the conjugate probe of Au–thiolate/Ce-based NSs was successfully applied for the selective and reliable GSH detection in human serum samples.