SBIR Phase I: Real-time, In-situ Detection of Escherichia Coli Bacteria in Water Using Graphene

This Small Business Innovation Research (SBIR) Phase I project aims to develop a graphene-gold nanoparticle-based sensing platform for detection of Escherichia Coli (E. Coli) bacteria in water. Real-time, inline detection of E. coli in water is an unmet need but critical for water quality monitoring to ensure public safety. Several methods have been used for E. coli detection in water; however, these methods have disadvantages such as low sensitivity, time-consuming, and high cost. Therefore, there is a great demand for sensitive, fast, and cost-effective detection technology that could address the limitations of conventional methods for E. coli detection. The intellectual merit of the SBIR Phase I project is realized by the superior sensing performance for the detection of E. coli and the application of graphene as the sensing element in a field-effect transistor sensor to fulfill unmet needs. Specific research objectives of the project are: (1) to improve the sensor sensitivity; (2) to test the sensor performance in flowing water; (3) to study the stability/reliability of the sensor; (4) to examine recycling potential of the sensor. The project is expected to lead to a reliable and low-cost E. coli sensor with a lower detection limit of 1 cfu/mL or below. The broader impact/commercial potential of this project will be realized by developing a new E. coli detection platform for improving public safety in the fresh water supply. The real-time, in-situ sensor will also contribute to a smart water distribution grid. The proposed activities will improve the biosensing performance (detection limit, stability, and recycling) and maximize the commercialization opportunities of the real-time sensing platform. The targeted commercial product will be a handheld, stand-alone unit that can be used to measure the E. coli concentration in well water, water from our faucets and refrigerators. The major sensing materials used in this platform, i.e., thermally-reduced graphene oxide and gold nanoparticles, are affordable, particularly given the small amount of materials needed for each sensor. The project is expected to generate a deeper understanding of the binding interaction between anti-bacterial antibody and bacteria, which will be useful for developing next-generation sensors for sensitive and accurate detection of food-borne and water-borne pathogens. The project will also train University of Wisconsin-Milwaukee postdocs and graduate students in the areas of nanomaterials and nanodevices.