磁纳米散射探针暗场超灵敏检测具核梭杆菌

Ultra-sensitive detection of Fusobacterium nucleatum with magnetic nanoparticle probe in dark-field

【背景】具核梭杆菌(Fusobacterium nucleatum)作为机会致病菌,能够引起许多感染性疾病,已被证实是促直肠癌发展的潜在重要危险因素,临床检测中亟需一种快速简单检测F.nucleatum的方法。【目的】通过建立一种磁纳米探针结合暗场显微镜直接观察计数的方法,可方便快速地检测样本中具核梭杆菌的数量。【方法】在磁纳米颗粒(magnetic nanoparticle,MNP)表面修饰制备的抗F.nucleatum抗体,构建一种特异性结合F.nucleatum的MNP探针。此外,比较MNP探针-暗场显微计数法与实时荧光定量PCR(qPCR)方法检测F.nucleatum的灵敏度。【结果】该方法的检测限可低至3.42×10^(1) copies/µL,比qPCR的灵敏度高5倍左右。在实际样本的检测中,该方法与qPCR方法所检测F.nucleatum数量保持一致。【结论】本研究建立的方法用于检测F.nucleatum,操作简单、检测快速(约30 min)、灵敏且成本低,有应用于临床样本检测的前景。

[Background]Fusobacterium nucleatum,an opportunistic pathogen causing infectious diseases,is a risk factor for the occurrence of colorectal cancer.Simple and rapid techniques are urgently needed for the detection of F.nucleatum in clinical practice.[Objective]In this study,we established a direct observation and counting method to count F.nucleatum cells in samples with magnetic nanoparticle(MNP)probe under dark-field microscopy.[Methods]We prepared the MNP probe by modifying MNPs with the homemade polyclonal antibodies against F.nucleatum,which can bind to F.nucleatum specifically.Furthermore,we compared the sensitivity of our method with that of real-time fluorescence quantitative PCR(qPCR)for detection of F.nucleatum.[Results]The method established in this study showed the limit of detection as low as 3.42×10^(1) copies/µL and the sensitivity 5 times higher than that of qPCR.For detection of the real samples,the results of ounting F.nucleatum by our method are consistent with that by qPCR.[Conclusion]The established method is simple,rapid(within about 30 min),sensitive,and economical for detecting F.nucleatum,which has the potential to serve the detection of clinical samples.