Rapid and facile electrospray preparation of CsPbBr3@PMMA fluorescent microspheres for fluorescent detection of ALP in biological samples

All-inorganic cesium lead halide perovskite quantum dots (QDs) have attracted more attention due to their excellent optoelectronic and photovoltaic properties. However, there are few applications in biochemical detection based on their unique photoluminescence property mainly because of the instability to external stimulus. In this work, we focus on a rapid preparation method of CsPbBr3@poly (methyl methacrylate) (PMMA) fluorescent composite microspheres based on electrospray to protect CsPbBr3 QDs from the external stimuli and stabilize them in aqueous environment. The CsPbBr3@PMMA composite microspheres effectively retained over 70% fluorescence intensity after being immersed in deionized water for 20 days. Based on the effective quenching of CsPbBr3@PMMA composite microspheres by MnO2 nanosheets, we developed a simple, label-free, low-cost, and facile fluorescent detection system for assay of alkaline phosphatase (ALP) in biological samples. The method shows a good linear relationship from 10.0 mU/mL to 100 mU/mL (R2 = 0.998) with the detection limit of 4.85 mU/mL and the recovery range of 95.1–110%. In summary, the PMMA coating can simply and effectively stabilize the CsPbBr3 QDs and preserve the luminescence of the CsPbBr3 QDs. The excellent applicability of the composite microspheres-based fluorescent detection system in human serum samples further demonstrates the potential application in the aqueous phase-based biochemical detection for clinical diagnosis and biomedical research.