He Mei-Ying, Lin Yu-Jen, Kao Yi-Ling, Kuo Pu, Grauffel Cédric, Lim Carmay, Cheng Yi-Sheng, Chou Hsin-Hung David
Department of Life Science, National Taiwan University, Taipei 106, Taiwan.
Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
ACS Sens. 2021 Mar 26;6(3):995-1002. doi: 10.1021/acssensors.0c02204. Epub 2021 Jan 14.
Whole-cell biosensors are useful for monitoring heavy metal toxicity in public health and ecosystems, but their development has been hindered by intrinsic trade-offs between sensitivity and specificity. Here, we demonstrated an effective engineering solution by building a sensitive, specific, and high-response biosensor for carcinogenic cadmium ions. We genetically programmed the metal transport system of to enrich intracellular cadmium ions and deprive interfering metal species. We then selected 16 cadmium-sensing transcription factors from the GenBank database and tested their reactivity to 14 metal ions in the engineered using the expression of the green fluorescent protein as the readout. The resulting cadmium biosensor was highly specific and showed a detection limit of 3 nM, a linear increase in fluorescent intensities from 0 to 200 nM, and a maximal 777-fold signal change. Using this whole-cell biosensor, a smartphone, and low-tech equipment, we developed a simple assay capable of measuring cadmium ions at the same concentration range in irrigation water and human urine. This method is user-friendly and cost-effective, making it affordable to screen large amounts of samples for cadmium toxicity in agriculture and medicine. Moreover, our work highlights natural gene repositories as a treasure chest for bioengineering.
全细胞生物传感器对于监测公共卫生和生态系统中的重金属毒性很有用，但它们的发展受到灵敏度和特异性之间内在权衡的阻碍。在这里，我们通过构建一种用于致癌镉离子的灵敏、特异且高响应的生物传感器，展示了一种有效的工程解决方案。我们对[具体生物名称]的金属转运系统进行基因编程，以富集细胞内的镉离子并去除干扰金属物种。然后，我们从GenBank数据库中筛选出16种镉感应转录因子，并以绿色荧光蛋白的表达作为读数，测试它们在工程化[具体生物名称]中对14种金属离子的反应性。所得的镉生物传感器具有高度特异性，检测限为3 nM，荧光强度在0至200 nM之间呈线性增加，最大信号变化为777倍。利用这种全细胞生物传感器、智能手机和低技术设备，我们开发了一种简单的检测方法，能够在相同浓度范围内测量灌溉水和人尿中的镉离子。该方法用户友好且具有成本效益，使得在农业和医学中筛选大量样品的镉毒性变得经济可行。此外，我们的工作突出了天然基因库作为生物工程宝库的作用。
