A Graphene-based Handheld Device for Rapid Detection of Escherichia coli Bacteria in Water

This SBIR Phase I project aims to develop a graphene-based handheld device for the rapiddetection of Escherichia coli (E. coli) bacteria in fresh water.Clean and safe water is crucial forhuman health sustainable agricultural and food production healthy ecosystems and prosperousindustries.Water quality monitoring is one of the core requirements for managing water resourcesand calls for accurate and accessible detection technologies to ensure quality control and earlywarning capabilities for users to minimize negative impacts. There is an unmet need for the real- time in situ and low-cost monitoring of biotic and abiotic contaminants in various water sources(e.g. surface water groundwater and process water).E. coli bacteria are among the mostprevalent pathogens that exist widely in the environment and can spread quickly and easily throughwater and food.A subspecies of E. coli referred to as Enterohaemorrhagic E. coli are mostdangerous pathogens commonly prevalent in the environment and are life-threatening to humans.The US EPA has recommended the use of E. coli in fresh water as an indicator organism.FDA'sFood Safety Modernization Act Produce Safety Rule has established water quality requirementsfor the safe growing harvesting packing and holding of fruits and vegetables grown for humanconsumption.Conventional approaches for E. coli detection in water have significant limitationssuch as a high cost long turn-around time (hours to days) and requirement of specialized operators.NanoAffix Science LLC (NAFX) proposes to develop a handheld device for sensitivespecific fast and cost-effective E. coli detection in fresh water.This device consists of: (i) amicro-sized sensor chip which is built upon a patented graphene-gold nanoparticle (NP) sensingplatform and integrated into a small test cell and (ii) a portable digital meter for direct display oftesting results.The graphene-Au NP sensing platform has superior performance over theconventional E. coli detection methods because of several innovative features (e.g. maximizedspecific surface area with monolayer and non-agglomerated graphene sheets stable and specificbinding sites for the bacterial cells through robust Au NPs conjugated with specific antibodies).Specific research objectives of the project are to: (1) improve the sensitivity and stability of the E.coli sensor chip; (2) investigate the specificity of the E. coli handheld device; (3) prototype ahandheld device with improved reproducibility and calibration; and (4) validate the handhelddevice performance against the gold standard and seek EPA and FDA approval.The project will lead to a portable handheld device (i.e. a test cell containing the sensorchip connected with a digital meter using a USB connector) for rapid measurements of E. coli(both pathogenic and generic).The device performance will meet requirements for real-time on- site E. coli detection in fresh water.The device is anticipated to fulfill an unmet need and play acritical role in improving water safety for consumption and agricultural food productionpreservation of surface waters and public health.The handheld device will help reduce thehealthcare cost from pathogenic bacteria-induced illnesses (100000 illnesses 3000hospitalizations 90 deaths and over $405 million cost annually in the US).The NAFX platformis versatile and can be engineered for a wide range of analytes (e.g. Legionella and Salmonella)with carefully-chosen specific probes.The microelectronics-based platform is conducive tointerface with wireless communication devices (e.g. smart phones) for remote sensing.