Tuberculosis (TB) has been a major public health problem, which can be better controlled by using accurate and rapid diagnosis in low-resource settings. A simple, portable, and sensitive detection method is required for point-of-care (POC) settings. This paper studies an amperometric biosensor using a microtip immunoassay for a rapid and low cost detection of Mycobacterium Tuberculosis (MTB) in sputum. MTB in sputum is specifically captured on the functionalized microtip surface and detected by electric current. According to the numerical study, the current signal on microtip surface is linearly changed with increasing immersion depth. Using a reference microtip, the immersion depth is compensated for a sensing microtip. On the microtip surface, target bacteria are concentrated and organized by a coffee ring effect, which amplifies the electric current. To enhance the signal-to-noise ratio, both the sample processing- and rinsing steps are presented with use of deionized water as a medium for the amperometric measurement. When applied to cultured MTB cells spiked into human sputum, the detection limit was 100 CFU/mL, comparable to a more labor-intensive fluorescence detection method reported previously.

中文翻译：

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用于快速检测结核分枝杆菌的电流免疫传感器

结核病 (TB) 一直是一个主要的公共卫生问题，可以通过在资源匮乏的环境中使用准确和快速的诊断来更好地控制。即时 (POC) 设置需要一种简单、便携且灵敏的检测方法。本文研究了一种使用微尖端免疫测定法快速、低成本检测痰中结核分枝杆菌 (MTB) 的电流生物传感器。痰中的 MTB 被功能化的微尖端表面特异性捕获并通过电流检测。根据数值研究，微尖端表面的电流信号随着浸入深度的增加而线性变化。使用参考微尖端，浸入深度补偿感应微尖端。在微尖端表面，目标细菌通过咖啡环效应聚集和组织，从而放大电流。为了提高信噪比，样品处理和冲洗步骤都使用去离子水作为电流测量的介质。当应用于掺入人类痰液中的培养 MTB 细胞时，检测限为 100 CFU/mL，与之前报道的劳动密集型荧光检测方法相当。