Preparation Of Quantum Dots And Quantum Dots/Polystyrene Fluorescent Microspheres And Its Application In Rapid Immunodetection Of Procalcitonin

Quantum dots are a new type of fluorescent material with unique optical properties such as broad UV-Vis absorption peaks,narrow but symmetrical fluorescence emission peaks and high fluorescence intensity.These excellent properties make quantum dots have broad application and prospects.However,limited by the small size of quantum dot,single quantum dot exhibits low fluorescence intensity.It is used in biomarkers when exposed to complex physiological conditions,easily destroying the fluorescence stability of quantum dots.So the quantum dots are loaded in the polymer microspheres to form quantum dot fluorescent microspheres..The synthesized quantum dots fluorescent microspheres can not only improve the fluorescence intensity of single microspheres but also easy to modify for bio-fluorescence labeling applications.As an important indicator to fungi,bacterial infection in the human body,procalcitonin(PCT)is of great importance for the clinical diagnosis of early diagnosis and timely treatment of infectious diseases.However,the common method for detection of PCT is neither quantification nor cheap,leading to a difficult promotion for PCT test in the grassroots community hospital.Fluorescence immunochromatography has the advantages of rapid quantification,high sensitivity and easy operation.With development of the fluorescence immunochromatography in detection of PCT,it will facilitate the prevention and treatment of infectious diseases.Therefore,it is of great significance to.develop a method with rapid quantification and easy operation of fluorescent immunochromatographic detection of PCT.This paper aims to synthesize CdSe/CdS core-shell quantum dots with high quantum yield.In order to improve the embedding efficience of CdSe/CdS quantum dots in polystyrene microspheres(PS),the 1-dodecanethiol(DDeT)was used to exchange ligands of quantum dot to obtain novel quantum dot/polystyrene fluorescent microspheres.And fluorescent microspheres were modified with PAH and PSS polyelectrolyte to prepare fluorescent labeled with PCT antibody probes,and used for fluorescence immunochromatography to detect PCT quickly and efficiently.The work in this paper is divided into the following three aspects:1.CdSe quantum dots were prepared by thermal injection method and then adopted in situ purification.The CdSe/CdS core-shell quantum dots with high quantum yield were prepared by the thermal cycle single precursor coupling method(TC-SP).The structure and optical properties of CdSe and CdSe/CdS quantum dots were characterized by UV-Vis,fluorescence emission,transmission electron microscopy and X-ray diffraction.The experimental results show that CdSe was successfully epitaxial growth on the surface of CdS.The prepared CdSe and CdSe/CdS quantum dots are face-centered cubic zinc-blende structure,which has a uniform size with high quantum yields.By exchanging the oleyl amine(OAm)ligands with DDeT,the optical properties of the quantum dots showed little change,and the solubility had been greatly improved,which had a positive effect on the subsequent preparation of fluorescent microspheres.2.Through the method of emulsion polymerization,the CdSe/CdS quantum dots were successfully loaded into polystyrene microspheres.It was found that the quantum dots distributed inside the microspheres were more homogeneous and had higher packing efficiency.The emulsion polymerization method successfully transferred the oil phase quantum dots to the aqueous phase,Fluorescent microspheres still remain narrow and symmetrical fluorescence emission spectra,and the fluorescence emission spectra of the peak position show no change.It is also proved that the embedding effiency of quantum dots is higher after ligand exchange.3.Fluorescent microspheres successfully modified with PAH and PSS polyelectrolytes.Fluorescence-labeled antibody probes were prepared by binding fluorescent microspheres to anti-procalcitonin monoclonal antibodies.The fluorescence immunoassay test strips were constructed and the test strips has been optimized and evaluated.It showed a great potential application for rapidly quantitative detection of PCT by fluorescence immunoassay device.