Green Synthesis of Gluten-Stabilized Fluorescent Gold Quantum Clusters: Application As Turn-On Sensing of Human Blood Creatinine

Protein mediated syntheses of fluorescent noble metal quantum clusters have proven to be particularly attractive owing to their high stability and biocompatibility. Here, we present the cost-effective synthesis of novel, water-soluble, and stable fluorescent gold quantum clusters via a facile and green method using wheat gluten protein as a stabilizing agent (Au-QC@gluten). Gluten, a cysteine-rich protein serves as an effective stabilizing agent for these clusters. The Au-QC@gluten shows intense red emission at similar to 680 nm and is characterized using UV-vis spectroscopy, fluorescence, Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Contrary to any other protein protected gold quantum cluster, Au-QC@gluten is highly stable toward reactive oxygen species like H2O2, revealing its promising application in biomedical fields such as bioimaging, biolabeling, etc. The red emitting Auqc@gluten has been applied in the detection of creatinine with high sensitivity and selectivity. The detection limit is found to be 2 nM in the linear range from 20 mu M to 520 mu M. This method allows the accurate detection of creatinine in clinical blood samples, indicating its promising biomedical applications.