Whole-cell biosensors have been regarded as a prominent alternative to chemical and physical biosensors due to their renewability, environmental friendliness, and biocompatibility. However, there is still a lack of noninvasive measurements of urine glucose, which plays a vital role in monitoring the risk of diabetes in the healthcare system, via whole-cell biosensors. In this study, we characterized a glucose-inducible promoter and further enhanced the sensing performance using three genetic effectors, which encompassed ribozyme regulator (RiboJ), clustered regularly interspaced short palindromic repeat interference (CRISPRi), and plasmid-based T7RNA polymerase (PDT7), to develop the noninvasive glucose biosensor by fluorescent signal. As a result, RiboJ increased dynamic range to 2989 au, but declined signal-to-noise (S/N) to 1.59, while CRISPRi-mediated NIMPLY gate intensified both dynamic range to 5720 au and S/N to 4.58. The use of single PDT7 orthogonal with T7 promoter in cells (i.e., P strain) achieved a 44 180 au of dynamic range with S/N at 3.08. By coupling the PDT7 and NIMPLY-mediated CRISPRi, we constructed an optimum PIGAS strain with the highest S/N value of 4.95. Finally, we adopted the synthetic bacteria into a microdevice to afford an integrative and portable system for daily urine glucose inspection, which would be an alternative approach for medical diagnosis in the future.

中文翻译：

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CRISPRi 介导的 NIMPLY 逻辑门，用于微调全细胞传感以实现简单的尿液葡萄糖检测

由于其可再生性、环境友好性和生物相容性，全细胞生物传感器被认为是化学和物理生物传感器的重要替代品。然而，仍然缺乏对尿糖的无创测量，这在监测医疗保健系统中的糖尿病风险方面起着至关重要的作用，通过全细胞生物传感器。在这项研究中，我们表征了一个葡萄糖诱导型启动子，并使用三种遗传效应器进一步增强了传感性能，其中包括核酶调节剂 (RiboJ)、成簇的规则间隔短回文重复干扰 (CRISPRi) 和基于质粒的 T7RNA 聚合酶 (PDT7) , 通过荧光信号开发无创葡萄糖生物传感器。结果，RiboJ 将动态范围增加到 2989 au，但将信噪比 (S/N) 降低到 1.59，而 CRISPRi 介导的 NIMPLY 门将动态范围增强到 5720 au，S/N 增强到 4.58。在细胞中使用与 T7 启动子正交的单个 PDT7（即, P 应变) 实现了 44 180 au 的动态范围，S/N 为 3.08。通过耦合 PDT7 和 NIMPLY 介导的 CRISPRi，我们构建了具有最高 S/N 值为 4.95 的最佳 PIGAS 菌株。最后，我们将合成细菌应用到微型设备中，提供了一个集成的便携式日常尿糖检测系统，这将成为未来医学诊断的替代方法。