目的建立一种以新型纳米材料——纳米荧光碳点(carbon dots,CDs)免疫示踪技术快速检测样本中细菌的方法。方法以检测乙型副伤寒沙门菌为例建立方法。用抗沙门菌Ha因子抗体耦联CDs制备成免疫纳米荧光碳点;用抗沙门菌O4因子抗体耦联磁珠粒对样本中乙型副伤寒沙门菌进行富集后,与抗Ha抗体耦联的CDs进行特异性结合,形成抗O4-磁珠粒-细菌-抗Ha-CDs"三明治"式免疫复合物;再用免疫亲和分离液移除复合物中的磁珠粒,借助荧光光谱仪测定分离液中CDs的荧光强度,推算出样品中致病菌的污染情况。结果抗Ha-CDs可有效结合抗O4-磁珠粒富集的细菌,对乙型副伤寒沙门菌的最低检测限为103CFU/mL,总时间约为2 h。结论建立的CDs技术可用于样本中乙型副伤寒沙门菌的快速检测。
Objective To develop an immune assay to rapidly detect the bacteria in samples by using fluorescent carbon dots(CDs) as tracer.Methods An immune assay to detect Salmonella paratyphi B was established.The antibody against Salmonella O 4 factor was conjugated to CDs to be immunofluorescent carbon dots,which were further used to enrich Salmonella paratyphi B in samples.Then,the antibody against Salmonella Ha conjugated CDs was added into the above-mentioned mixture to form a sandwich immunocomplex as anti-O 4-CDs-Salmonella paratyphi B-anti-Ha-CDs.After being purified with a magnetic separator,the immunocomplex were further cleaved using the immunoaffinity separation buffer to release CDs for the fluorescence detection and the quantitation of Salmonella paratyphi B in samples.Results Anti-Ha-CDs may bind Salmonella paratyphi B enriched by anti-O 4-CDs effectively.The lowest detectable limit was 103CFU / mL and the whole detection period was about two hours for the established immunoassay.Conclusion The established immunoassay by the CDs technique can rapidly detect Salmonella paratyphi B in samples.