Maltose-functionalized MAPbBr3 fluorescent perovskite quantum dots with strong water resistance for detection of γ-aminobutyric acid as a neurological biomarker

Zero-dimensional perovskite nanostructures have always been shown outstanding applications in recognizing gases and molecular species. Herein, maltose (Malt) was introduced as an encapsulating agent for the synthesis of MAPbBr(3) fluorescent perovskite quantum dots (Malt@MAPbBr(3) PQDs), showing strong water resistance and good quantum yield (QY). The as-synthesized Malt@MAPbBr(3) PQDs have an average size of 7.25 +/- 2.63 nm. The structure and elemental composition of Malt@MAPbBr(3) PQDs are confirmed by various analytical techniques. The as-synthesized Malt@MAPbBr(3) PQDs display remarkable fluorescence characteristics (lambda Ex/Em = 430/535 nm) with QY of 23.74 %. The selectivity of various biomarkers (epinephrine, normetanephrine, creatinine, dehydroepiandrosterone, uric acid, bilirubin, methyl nicotinate, gamma-aminobutyric acid (GABA), Semethylselenocystiene, and cortisone) on the fluorescence quenching of Malt@MAPbBr(3) PQDs was studied through fluorescence emission spectroscopy. Interestingly, Malt@MAPbBr(3) PQDs exhibit a noticeable fluorescence quenching (>90 %) with the limit of detection (8.37 nM) in the presence of GABA. The developed Malt@MAPbBr(3) PQDs-based fluorescent sensor is successfully applied to detect GABA in biofluids.