Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Tianjin University), Ministry of Education, Tianjin, China.
Appl Environ Microbiol. 2019 May 16;85(11). doi: 10.1128/AEM.00694-19. Print 2019 Jun 1.
Whole-cell biosensors (WCBs) have been designed to detect As(III), but most suffer from poor sensitivity and specificity. In this paper, we developed an arsenic WCB with a positive feedback amplifier in DH5α. The output signal from the reporter mCherry was significantly enhanced by the positive feedback amplifier. The sensitivity of the WCB with positive feedback is about 1 order of magnitude higher than that without positive feedback when evaluated using a half-saturation As(III) concentration. The minimum detection limit for As(III) was reduced by 1 order of magnitude to 0.1 µM, lower than the World Health Organization standard for the arsenic level in drinking water, 0.01 mg/liter or 0.13 µM. Due to the amplification of the output signal, the WCB was able to give detectable signals within a shorter period, and a fast response is essential for operations. Moreover, the WCB with the positive feedback amplifier showed exceptionally high specificity toward As(III) when compared with other metal ions. Collectively, the designed positive feedback amplifier WCB meets the requirements for As(III) detection with high sensitivity and specificity. This work also demonstrates the importance of genetic circuit engineering in designing WCBs, and the use of genetic positive feedback amplifiers is a good strategy to improve the performance of WCBs. Arsenic poisoning is a severe public health issue. Rapid and simple methods for the sensitive and specific monitoring of arsenic concentration in drinking water are needed. In this study, we designed an arsenic WCB with a positive feedback amplifier. It is highly sensitive and able to detect arsenic below the WHO limit level. In addition, it also significantly improves the specificity of the biosensor toward arsenic, giving a signal that is about 10 to 20 times stronger in response to As(III) than to other metals. This work not only provides simple but effective arsenic biosensors but also demonstrates the importance of genetic engineering, particularly the use of positive feedback amplifiers, in designing WCBs.
全细胞生物传感器 (WCBs) 已被设计用于检测 As(III)，但大多数都存在灵敏度和特异性差的问题。在本文中，我们在 DH5α 中设计了一种带有正反馈放大器的砷生物传感器。报告基因 mCherry 的输出信号通过正反馈放大器得到显著增强。当使用半饱和 As(III)浓度评估时，具有正反馈的 WCB 的灵敏度比没有正反馈的 WCB 高约 1 个数量级。As(III)的最低检测限降低了 1 个数量级，至 0.1µM，低于世界卫生组织规定的饮用水砷含量标准，即 0.01mg/liter 或 0.13µM。由于输出信号的放大，WCB 能够在更短的时间内给出可检测的信号，快速响应对于操作至关重要。此外，与其他金属离子相比，具有正反馈放大器的 WCB 对 As(III)表现出异常高的特异性。总的来说，设计的正反馈放大器 WCB 具有高灵敏度和特异性，满足对 As(III)进行检测的要求。这项工作还证明了遗传电路工程在设计 WCB 方面的重要性，使用遗传正反馈放大器是提高 WCB 性能的良好策略。砷中毒是一个严重的公共卫生问题。需要快速、简单的方法来灵敏、特异性地监测饮用水中的砷浓度。在这项研究中，我们设计了一种带有正反馈放大器的砷生物传感器。它具有很高的灵敏度，能够检测到低于世界卫生组织限量水平的砷。此外，它还显著提高了生物传感器对砷的特异性，使其对 As(III)的响应信号比其他金属强 10 到 20 倍。这项工作不仅提供了简单而有效的砷生物传感器，还展示了遗传工程，特别是正反馈放大器的使用，在设计 WCB 方面的重要性。
