Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China.
Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China; Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, PR China.
Biosens Bioelectron. 2024 Jul 15;256:116283. doi: 10.1016/j.bios.2024.116283. Epub 2024 Apr 9.
Due to the toxicity of mercury and its harmful effects on human health, it is essential to establish a low-cost, highly sensitive and highly specific monitoring method with a wide detection range, ideally with a simple visual readout. In this study, a whole-cell biosensor with adjustable detection limits was developed for the detection of mercury ions in water samples, allowing controllable threshold detection with an expanded detection range. Gene circuits were constructed by combining the toehold switch system with lactose operon, mercury-ion-specific operon, and inducible red fluorescent protein gene. Using MATLAB for design and selection, a total of eleven dual-input single-output sensing logic circuits were obtained based on the basic logic of gene circuit construction. Then, biosensor DTS-3 was selected based on its fluorescence response at different isopropyl β-D-Thiogalactoside (IPTG) concentrations, exhibiting the controllable detection threshold. At 5-20 μM IPTG, DTS-3 can achieve variable threshold detection in the range of 0.005-0.0075, 0.06-0.08, 1-2, and 4-6 μM mercury ion concentrations, respectively. Specificity experiments demonstrated that DTS-3 exhibits good specificity, not showing fluorescence response changes compared with other metal ions. Furthermore spiked sample experiments demonstrated its good resistance to interference, allowing it to distinguish mercury ion concentrations as low as 7.5 nM by the naked eye and 5 nM using a microplate reader. This study confirms the feasibility and performance of biosensor with controllable detection threshold, providing a new detection method and new ideas for expanding the detection range of biosensors while ensuring rapid and convenient measurements without compromising sensitivity.
由于汞的毒性及其对人类健康的有害影响，建立一种低成本、高灵敏度、高特异性、检测范围广的监测方法至关重要，理想情况下还应具有简单的目视读数功能。在这项研究中，开发了一种具有可调检测限的全细胞生物传感器，用于检测水样中的汞离子，允许进行可控的阈值检测，并具有扩展的检测范围。通过将碱基对开关系统与乳糖操纵子、汞离子特异性操纵子和诱导型红色荧光蛋白基因相结合，构建了基因电路。使用 MATLAB 进行设计和选择，基于基因电路构建的基本逻辑，共获得了十一个双输入单输出传感逻辑电路。然后，根据不同异丙基β-D-硫代半乳糖苷 (IPTG) 浓度下的荧光响应，选择了生物传感器 DTS-3，其具有可控的检测阈值。在 5-20 μM IPTG 下，DTS-3 可以在 0.005-0.0075、0.06-0.08、1-2 和 4-6 μM 汞离子浓度范围内实现可变阈值检测。特异性实验表明，DTS-3 具有良好的特异性，与其他金属离子相比，没有表现出荧光响应的变化。此外，加标样品实验表明，它具有良好的抗干扰能力，能够通过肉眼区分低至 7.5 nM 的汞离子浓度，使用微孔板读数器可区分低至 5 nM 的汞离子浓度。这项研究证实了具有可控检测阈值的生物传感器的可行性和性能，为生物传感器的检测范围扩展提供了一种新的检测方法和新的思路，同时在不影响灵敏度的情况下确保了快速方便的测量。
