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

点击翻译按钮获取中文摘要

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.