Objective To develop an assay incorporating cadmium selenide quantum dots (QDs) for the detec-tion of mycobacterial surface antigens. Methods The bacterial cells were separated using magnetic beads coupled with genus-specific polyclonal antibodies and monoclonal antibodies for heparin-binding hemagglutinin. These complexes were then detected with anti-mouse biotinylated antibody and finally streptavidin-conjugated QDs which leads to the de-tection of a fluorescent signal. To evaluate the feasibility of the method, Mycobacterium bovis BCG and Mycobacterium tuberculosis (positive controls), as well as E. coli and Salmonella spp. that constituted the negative controls were applied. Results Mycobacterium cells could directly be detected using acid-fast staining method after Mycobacterium cells were separated using immunomagnetic beads. The direct observation of negative samples did not reveal fluorescence as opposed to the mycobacteria mentioned above. The minimum detection limit of the assay was defined to 104 bacteria/mL, which could be further decreased up to 103 bacteria/mL when fluorescence was measured with a spectrofluorometer. Conclusion The method described here can be easily applied for the pathogens including Mycobacterium tuberculosis, implying that this method has potential application for various different pathogens.%目的 探讨利用荧光量子点(QDs)开发新一代结核分枝杆菌的检测方法.方法 采用特异性多克隆抗体偶联到磁珠上用于结核杆菌的分离和富集,然后用标记QDs的链霉亲和素检测结合生物素标记的肝素血凝素(HBHA)单克隆抗体的结核杆菌.采用牛结核分枝杆菌和结核分枝杆菌作为阳性样品,以大肠杆菌和沙门氏菌作为阴性对照,以评估该方法的可行性.结果 用抗酸染色能检测到磁珠分离和富集的结核杆菌,直接观察没有发现阴性对照有荧光,但阳性对照可以观察到荧光.直接观察法的检测限为104细菌/mL.当采用荧光光度计检测样品时,其检测限可以达到103细菌/mL.结论 该方法能适用于包括结核分枝杆菌病原体的检测,是一种具有前景的病原体的检测方法.
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