Design and construction of electrogenic cell-based biosensors for pathogens and toxins

传统的以实验室为基础的细菌病原体和环境毒素分析方法昂贵、耗时，通常需要专业人员和复杂(昂贵)的设备。这限制了它们在资源有限的农村地区和发展中国家的使用，这些地区缺乏足够的熟练人员和医疗保健设施，无法迅速识别风险。因此，迫切需要为与致命性细菌感染和受污染的日常资源相关的病原体和毒素提供简单、经济、快速的现场传感解决方案。例如，受霍乱弧菌污染的水或食物通常是腹泻疾病霍乱的罪魁祸首，霍乱可导致严重脱水，甚至在几小时内死亡。铜绿假单胞菌是一种机会致病菌，常见于导管等医疗器械表面，对免疫功能低下的人群具有致命性。地下水中的砷污染在世界上许多地方都有发现，特别是在孟加拉国，那里超过一半的人口面临着砷中毒的风险，砷中毒可能会导致癌症和各种皮肤病。一种简单、经济、高效的传感解决方案，能够准确、快速地报告这些严重的健康危害，对于预防这些疾病的流行并有助于改善公众健康和生活质量至关重要。在这个项目中，我们将建立一种基于自主细胞的生物传感器的开发路线，具有直接数字电子输出，用于经济高效地现场检测与致命细菌传染病或受污染资源相关的病原体和环境毒素。不同的基因编码传感器将被构建并放置在活的良性肠道细菌大肠杆菌中，以监测病原体分泌的特定毒素或指纹分子的外观。然后，通过定制的遗传电路进一步放大和调制被转换的传感信号，以提高传感灵敏度和选择性。一旦检测到目标病原体或毒素，基因工程细菌细胞将开启电子穿梭的生产，在一种名为微生物燃料电池的设备中产生电力，该设备利用修饰后的细菌将有机物转化为电能。因此，自主细胞生物传感器能够在不使用特定分析设备的情况下为电子系统供电并报告相关的病原体或毒素水平。这项研究在目前集成度较低的蜂窝和电子系统之间建立了一条合成电子管道，并将在环境、农业和医疗环境中找到许多应用。该项目还将向新兴领域贡献新的设计工具和方法、新的监管部件和设备，即在活微生物中部署非本地生物系统，以改变对人类有益的行动。

The traditional laboratory-based analytical assays for bacterial pathogens and environmental toxins are expensive, time consuming and normally require specialised personnel and complex (expensive) equipment. This restricts their use in resource limited rural areas and developing countries where lack sufficient skilled personnel and healthcare facilities to rapidly identify the risks. There is therefore an urgent need to provide simple cost effective, fast on-site sensing solutions for pathogens and toxins associated with fatal bacterial infections and contaminated daily resources. For example, Vibrio cholerae bacteria contaminated water or food are typically responsible for the diarrheal illness cholera that can result in severe dehydration and even death within a matter of hours. Pseudomonas aeruginosa, commonly found on the surface of medical equipments such as catheters, is an opportunistic human pathogen and can be fatal for immunity compromised population. Arsenic contamination of groundwater is found in many places in the world, especially in Bangladesh where more than half of the population are facing the risk of arsenic poisoning which can cause cancers and various skin diseases. A simple, cost effective sensing solution that can accurately and rapidly report these severe health hazards will be vital to prevent the prevalence of these diseases and contribute to improved public health and quality of life.In this project we will establish a route to develop autonomous cell-based biosensors with direct digital electrical output for cost effective, on-site detection of pathogens and environmental toxins associated with fatal bacterial infectious diseases or contaminated resources. Different genetically coded sensors will be constructed and placed inside living benign gut bacteria Escherichia coli to monitor the appearance of specific toxin or fingerprinting molecules secreted by pathogen. The transduced sensory signals then further undergo amplification and modulation via customised genetic circuits to enhance sensing sensitivity and selectivity. Upon the detection of target pathogen or toxin, the genetically engineered bacterial cells will switch on the production of an electron shuttle to generate electrical power in a device known as microbial fuel cell, which utilises the modified bacteria to convert organic matter into electricity. As a result, autonomous cellular biosensors are constructed with the ability to power and report the associated pathogen or toxin levels to electronic systems without the use of specific assay equipment. The research builds a synthetic electron conduit between the currently less integrated cellular and electronic systems and will find many applications in environmental, agricultural and medical settings. The project will also contribute new design tools and methods, novel regulatory components and devices to the emerging field of deploying non-native biological systems in living microbes for repurposed actions of benefit to man.