Real-time monitoring of estrogenic activity in the aquatic environment is a challenging task. Current biosensors face difficulties due to their limited response speed and environmental tolerance, especially for detecting wastewater, the major source of estrogenic compounds in aquatic environments. To address these difficulties, this study developed a single fluorescent protein (FP) -based whole-cell bacterial biosensor named ER-Light, which was achieved by inserting the sensing domain of the estrogen receptor (ER) into the FP Citrine and expressing it in the periplasm of Escherichia coli. As designed, ER-Light enables the detection of net estrogenic activity in mixtures, represented by estradiol equivalent concentration (EEQ). ER-Light detects EEQ in 40 s with a detection limit of 4.55 × 10⁻⁷ μM and a maximum working range of 1.1 × 10⁻⁴ μM, demonstrating sufficient response speed, sensitivity, and working range. In addition, the ER-Light can survive and tolerate wastewater effluent. Satisfactory recoveries (91.0 % to 102.1 %) eliminated concerns about the matrix effect of wastewater. EEQs (Not detected-2.9 ×10⁻⁵ µM) measured by ER-Light from the effluent of 9 wastewater treatment plants validate its practicality in detecting wastewater. This is the first attempt to integrate ER into FP-based biosensors for environment monitoring. Our findings provide valuable design rules for real-time detection of bioactivity effects in the environment, contributing to the safeguarding of ecological and human health.

中文翻译：

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一种基因编码的荧光全细胞生物传感器，用于实时检测水样中的雌激素活性


实时监测水生环境中的雌激素活性是一项具有挑战性的任务。当前的生物传感器由于其有限的响应速度和环境耐受性而面临困难，尤其是在检测废水方面，废水是水生环境中雌激素化合物的主要来源。为了解决这些困难，本研究开发了一种名为 ER-Light 的基于荧光蛋白 （FP） 的全细胞细菌生物传感器，这是通过将雌激素受体 （ER） 的传感域插入 FP 黄水晶并在大肠杆菌的周质中表达来实现的。按照设计，ER-Light 能够检测混合物中的净雌激素活性，以雌二醇当量浓度 （EEQ） 表示。ER-Light 可在 40 秒内检测 EEQ，检测限为 4.55 × ^10-7 μM，最大工作范围为 1.1 × ^10-4 μM，表现出足够的响应速度、灵敏度和工作范围。此外，ER-Light 可以存活并耐受废水排放。令人满意的回收率（91.0% 至 102.1%）消除了对废水基质效应的担忧。ER-Light 从 9 个污水处理厂的污水中测量的 EEQ（未检测到 2.9 ×10⁻⁵ μM）验证了其在检测废水方面的实用性。这是将 ER 集成到基于 FP 的生物传感器中以进行环境监测的首次尝试。我们的研究结果为实时检测环境中的生物活性影响提供了有价值的设计规则，有助于保护生态和人类健康。