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

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.