基于CdSe/ZnS核壳型量子点的高灵敏、快速细菌计数新方法的研究

A Highly Sensitive and Rapid Bacteria-Counting New Approach Based on CdSe/ZnS Core/Shell Quantum Dots

以乙酰丙酮镉和硬脂酸锌为前驱体,合成了巯基丙酸修饰的CdSe/ZnS核壳型量子点(QDs)。并将其作为荧光探针,以金黄色葡萄球菌(S.aureus)为目标细菌,建立了一种高灵敏的、简单快速的细菌计数新方法,并借助荧光显微镜成功的进行成像探测研究。通过考察量子点浓度、孵育时间等因素的影响,确定了细菌定量检测的最佳条件。在最优化的实验条件下,体系的相对荧光强度随细菌数量的增加而增大。该方法的线性范围为102CFU/mL～106CFU/mL,检测限为102CFU/mL,线性回归方程为Y=427.586X-677.022(R=0.996 49)。本方法有效克服了传统的细菌计数方法存在的缺陷,具有较高的灵敏度和较好的重现性(实际样品检测的RSD=3.6%～8.1%),且操作简单、检测时间短、成本低,有很好的潜在应用价值。

The mercaptopropionic acid functionalized CdSe/ZnS core/shell quantum dots（QDs） were synthesized with cadmium acetylacetonate and zinc stearate as precursors.A high sensitive,simple and rapid bacteria counting approach was established by using QDs as a fluorescence label,Staphylococcus aureus（S.aureus） acted as detection target bacteria.The bacterial cell images were obtained using fluorescence microscopy.The effect of parameters such as concentration of CdSe/ZnS and reaction time are discussed.Under the optimized conditions,a linear relationship of the fluorescence peak intensity（Y） and the total bacterial count（X） was established in the range of 10 2 CFU/mL ～ 10 6 CFU/mL using the equation Y = 427.586X-677.022（R = 0.996 49） with the detection limit of 10 2 CFU/mL.This new method shows a bright application prospect for detection of the total bacterial count due to its several advantages such as high sensitivity,reproducibility（RSD = 3.6% ～ 8.1%） technically simple,rapid and inexpensive while compared with traditional detection method.