Preparation Of Encapsulated Lead Bismuth Bromide Quantum Dots Polymer Microspheres Based On Electrospray For Detection Of Alkaline Phosphatase

In recent years,all-inorganic perovskite quantum dots,as a new type of fluorescent nanomaterial,have attracted much attention from researchers in various fields due to their excellent luminescent properties such as high quantum yield,narrow half-peak width,and adjustable wavelength.However,such quantum dot is extremely easy to decompose in polar solvents and loses its fluorescent properties,which greatly limits its application in bioanalytical detection.In this paper,we used electrospray technology to encapsulate CsPbBr3 quantum dots by polymethyl methacrylate(PMMA),and prepared CsPbBr3@PMMA fluorescent microspheres which can be stably exsit in aqueous solution.The microspheres prepared above were finally used to detect alkaline phosphatase(ALP)in human serum,which was successfully applied in the field of bioanalytical detection.In the first chapter,a brief introduction of the composition and properties of all inorganic perovskite quantum dots is given,and summarized the common methods for preparing CsPbBr3 quantum dots and their application fields.Secondly,the mechanism of electrospray technology for particle preparation and its important applications in various fields are introduced.Finally,the significance of ALP detection and the commonly used detection methods are expounded.In the second chapter,the CsPbBr3 quantum dots were first prepared by one-pot method.The quantum dots were then characterized by scanning electron microscopy,fluorescence spectroscopy and X-ray diffraction and so on.Then we prepared CsPbBr3@PMMA fluorescent microspheres by electrospray technique.The fluorescent microspheres were characterized by fluorescence,ultraviolet absorption and upright fluorescence spectra.Finally,we investigated the fluorescence intensity of fluorescent microspheres with unencapsulated quantum dots in aqueous solution to compare the stability of the two in aqueous solution.In the third chapter,manganese dioxide nanosheets used as a fluorescence quencher to quench the fluorescence of CsPbBr3@PMMA microspheres.L-ascorbic acid-2-phosphate trisodium salt(AAP)was introduced into the reaction system,followed by the addition of the test substance ALP,which catalyzes the production of ascorbic acid(AA)by AAP.After AA reduces the manganese dioxide nanosheet to divalent manganese ions,the manganese dioxide nanosheet loses its fluorescence quenching ability,and the fluorescence signal of the microsphere recovers.We quantitatively detect ALP based on changes in fluorescence intensity signals.The linear range of ALP detection in this experimental method was 10.0-100 mU/mL,and the detection limit was 4.85 mU/mL.Finally,the blood samples of healthy volunteers were selected for spiked experiments.The recovery rate of the actual samples was in the range of 95.1%-108%,indicating that the method has the potential to be applied into practical sample detection..In the fourth chapter,the overall experimental ideas of this paper are summarized,and the potential applications of all perovskite quantum dots in bioanalysis are prospected.