【摘要】 目的制备CdSe/CdZnS核壳结构量子点并将其作为荧光探针对大肠杆菌O157进行生物标记,为建立病原微生物的量子点标记快速检测新技术提供科学依据。方法利用高温有机合成方法制备CdSe/CdZnS核壳结构量子点,采用透射电镜、荧光光谱、吸收光谱进行表征。以巯基乙酸为稳定剂将量子点转移到水相并对大肠杆菌O157进行标记,利用荧光显微镜进行表征。结果制备的CdSe/CdZnS核壳结构量子点尺寸均匀,分散性良好,粒径为5~6 nm,发光峰半峰宽为23 nm。标记量子点上的细菌在365 nm激发下发出明显红光,且形态清晰,边界分明。当菌体浓度低于3.6×106cfu/ml时对量子点荧光强度具有增效作用,随着细菌浓度增大量子点荧光强度增强。结论制备的CdSe/CdZnS核壳结构量子点可用于大肠杆菌O157的快速检测。更多还原

【Abstract】 Objective To investigate the preparation of Cd Se / Cd Zn S core / shell quantum dots( QDs)and their preliminary usage as fluorescence probes of E.Coli O157,so as to provide a scientific basis for the establishment of new technology for rapid detection of pathogenic microorganisms.Methods Firstly,the high luminescent Cd Se / Cd Zn S core / shell quantum dots emitting in the red range were synthesized by the high temperature soft colloidal chemical method,and were characterized by transmission electron microscopy,emission spectra and absorption spectrum.Then the quantum dots were transferred to the aqueous phase using mercaptoacetic acid as stabilizer.Finally,E.coli O157 was marked by the water-soluble QDs and characterized by fluorescence microscopy.Results The Cd Se / Cd Zn S core / shell quantum dots had very uniform size and good dispersion.The particle diameter was 5 ~ 6 nm and the photoluminescence half peak width was 23 nm.Under 365 nm excitation,the bacteria marked by quantum dots emited visible red light and had the clear form and border.When the cell concentration was lower than 3.6 × 106 cfu / ml,the bacteria had a synergistic effect on the fluorescence intensity of quantum dots.The intensity of fluorescence quantum point reinforced with the increase of the concentration of bacteria.Conclusion The Cd Se / Cd Zn S core / shell quantum dots can be used in the rapid detection of E.coli O157.更多还原