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High Throughput Salmonella Detector

Torija, M. A.
Advanced Technologies Nve Corporation
Start date
End date
The primary goal of the Phase II program is to develop a prototype benchtop sensor system that accepts a 100ml sample, preconcentrates it, and provides a yes-or-no indication of Salmonella enterica in less than 20minutes. We will accomplish this goal by completing the following technical objectives:Optimize sensor and concentrator surface treatments to minimize chemical adherence, reduce reactions from other matrix elements, and maximize magnetic particle adherence. In phase I, channel clogging problems were anticipated but not fully resolved.Develop a magnetophoretic device that successfully separates unbound magnetic nanoparticles from bound Salmonella-MNP conjugates with at least 99% efficiency. Removing unbound MNP is important to minimize false positives. Other chip-scale separation technologies such as dielectric electrophoresis will be considered if necessary.Develop scalable multichannel electronic signal processing that supports two 16×16 sensor arrays. Phase I prototype measurements were made with laboratory electronics on individual sensors. The Phase II design will be built from discrete components on printed circuit boards to create a standalone test system.Develop a pre-measurement sample preparation protocol for filtration and magnetic concentration using commercially available tools. This protocol will ensure that the sample fluids are sufficiently mixed with functionalized MNPs for effective Salmonella-MNP tagging. Filtration must remove particulates large enough to plug sensor holes without removing Salmonella. The ratio of sample volume and MNPs will also be optimized.MicroPlumbers Microsciences (MPM) and Diagnostic Biosensors (DiagBio). Develop a microfluidic manifold for the fluidic samples with electrical connections to two sensor chips, the magnetophoretic concentrator, and electronics.University of Florida (UF). Scale MNP coating processes for commercial manufacturing. Functionalized MNPs have been produced in small quantities suitable for prototyping. A large-scale process is needed for commercialization.University of Minnesota (UMN). Complete additional SELEX processes to refine the Salmonella enterica aptamer. Additional characterization including imaging number of MNP per bacteria will further enhance sensor efficacy.Demonstrate a compact benchtop detection system with a sample preparation protocol, magnetophoretic separator, integrated next-generation sensor chip, test electronics and software.Evaluate the prototype system for accuracy and lowest detectable limit. The goal of one CFU will be statistically compared to qPCR for several Salmonella enterica serovars.The sensor system will be documented and a datasheet and other collaterals generated for sales and marketing.
Funding Source
Nat'l. Inst. of Food and Agriculture
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Prevention and Control