SBIR Phase I: Handheld graphene-based sensors for rapid detection of Salmonella species in food processing facilities

The broader impact of this Small Business Innovation Research (SBIR) Phase I project is faster and accurate detection of Salmonella species in food processing plants. Salmonella bacteria are the most frequently reported cause of foodborne illness. Food contamination in processing facilities can lead to serious public health problems as well as costly recalls of millions of food units. Rapid and accurate sensing technology is currently lacking for definitive detection of Salmonella in food-processing plants, which delays initiation of appropriate control measures and increases the likelihood of spreading contamination and foodborne illnesses to consumers. This technology will enable more frequent testing throughout the entire manufacturing process at reduced costs. It is fully expected that this technology could be applied to the detection of other pathogens. The proposed project will create and test a rapid (20 minutes), hand-held, sensitive (1 bacteria cell per milliliter) platform to enable food-processing facilities to detect Salmonella on site. The innovation of this technology lies in the ability to avoid bacterial enrichment (22 to 48 hours to allow bacteria to grow), while still sensitively and selectively detecting Salmonella species. The device uses a testing cartridge to bring bacteria directly to a detection surface, which consists of graphene printed or scribed on a test-strip and subsequently functionalized with Salmonella-specific antibodies. Unique laser processing induces a 3D-structured surface at the nanoscale level in graphene that becomes highly conductive for biosensing and for antibody attachment, which are desirable properties for enabling low detection limits and increasing test sensitivity. These technologies can be combined into a portable platform to make a user-friendly handheld biosensor and displaying quantitative counts of bacteria. The integrated platform (test strip and cartridge) will be designed to interface with existing portable electrical readers in much the same fashion that diabetics monitor blood glucose levels at home with a blood test strip that connects to a portable reader with a digital display. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.