Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Tuberculosis (Edinb). 2012 Sep;92(5):407-16. doi: 10.1016/j.tube.2012.05.009. Epub 2012 Jun 17.
Early diagnosis of active tuberculosis (TB) remains an elusive challenge, especially in individuals with disseminated TB and HIV co-infection. Recent studies have shown a promise for the direct detection of pathogen-specific biomarkers such as lipoarabinomannan (LAM) for the diagnosis of TB in HIV-positive individuals. Currently, traditional immunoassay platforms that suffer from poor sensitivity and high non-specific interactions are used for the detection of such biomarkers. In this manuscript, we demonstrate the development of sandwich immunoassays for the direct detection of three TB-specific biomarkers, namely LAM, early secretory antigenic target 6 (ESAT6) and antigen 85 complex (Ag85), using a waveguide-based optical biosensor platform. Combining detection within the evanescent field of a planar optical waveguide with functional surfaces that reduce non-specific interactions allows for the ultra-sensitive and quantitative detection of biomarkers (an order of magnitude enhanced sensitivity, as compared to plate-based ELISA) in complex patient samples (urine, serum) within a short time. We also demonstrate the detection of LAM in urine from a small sample of subjects being treated for TB using this approach with excellent sensitivity and 100% corroboration with disease status. These results suggest that pathogen-specific biomarkers can be applied for the rapid and effective diagnosis of disease. It is likely that detection of a combination of biomarkers offers greater reliability of diagnosis, rather than detection of any single pathogen biomarker. NCT00341601.
早期诊断活动性结核病（TB）仍然是一个难以实现的挑战，尤其是在患有播散性结核病和 HIV 合并感染的个体中。最近的研究表明，直接检测病原体特异性生物标志物（如脂阿拉伯甘露聚糖（LAM））有望用于诊断 HIV 阳性个体的结核病。目前，用于检测此类生物标志物的传统免疫分析平台存在灵敏度差和非特异性相互作用高的问题。在本文中，我们展示了使用基于波导的光学生物传感器平台开发用于直接检测三种 TB 特异性生物标志物（即 LAM、早期分泌抗原靶 6（ESAT6）和抗原 85 复合物（Ag85））的夹心免疫测定法。通过将检测与平面光学波导的倏逝场结合，并使用减少非特异性相互作用的功能表面，可在短时间内（与基于平板的 ELISA 相比，灵敏度提高了一个数量级）对复杂患者样本（尿液、血清）中的生物标志物进行超灵敏和定量检测。我们还通过这种方法检测了一小部分正在接受结核病治疗的患者尿液中的 LAM，具有出色的灵敏度，并且与疾病状态完全一致。这些结果表明，病原体特异性生物标志物可用于快速有效地诊断疾病。很可能检测多种生物标志物比检测任何单一病原体生物标志物具有更高的诊断可靠性。NCT00341601。
