This Small Business Innovation Research Phase I project proposes to develop a state-of-the-art microfluidic technology for pathogen and toxin diagnostics in drinking water. The innovation stems from our ability to transfer enzyme linked immunosorbent assay (ELISA) to an integrated microfluidic format that has a fully automated platform for microparticle label immunoassays. By using fluorescence detection, we can achieve sub-ppb levels of detection sensitivities for a variety of chemicals and toxins in low concentrations in water to meet the stringent regulatory requirement. The proposed technology has a handheld platform, designed to perform simultaneous detections of multiple toxins with a degree of sensitivity and specificity only currently achievable with laboratory based instruments. Compared with laboratory based methods, on site portable detection platform offers these advantages: (1) reduction in time and cost, (2) real-time data for better and timely decision making, and (3) reduction in sample consumption. In Phase I, the technical feasibility will be demonstrated through simultaneous detection and identification of microcystins and other cyanobacteria toxins as a proof-of-concept. In the follow-on Phase II effort, we will build and test a prototype and extend the diagnostics capability to other water-based pathogens and toxins.
The broader impact/commercial potential of this project encompasses environmental monitoring of Harmful Algal Bloom (HAB) toxins. Most of the current diagnostic methods that have high detection sensitivity and specificity such as biological assays and chromatography are all laboratory based. This requires having to take the samples from the field to the laboratory for analysis, often a time consuming and costly process. The lack of real-time data also hampers proper and timely decision making such as an early warning system. Current portable technologies such as electrochemical detections do not have the sensitivity and specificity of laboratory based instruments. Our portable field deployable technology has a miniature and automated format. Automation allows for precise fluid control, real-time data collection and analysis, eliminates the need for manual sample preparation, and prevents contamination between operations. Moreover, the programmable nature of the platform enables the integrated microfluidic technology to have broader commercial application to include diagnostics of a broader class of pathogens and toxins beyond HAB toxins. If successful, the technology can be a powerful analytical tool for monitoring a variety of toxins present in food, water, and soil. The key target customers include resource managers, public health officials, and aquaculture facilities.
In this NSF SBIR Phase I effort, HJ Science & Technology, Inc. has established the technical feasibility of a novel portable microfluidic platform for performing automated immunoassay for a variety of water-based toxins with multiplexing capability. The microfluidic automation technology demonstrated in the Phase I effort is inexpensive, easy to use and has a portable platform, designed to address several shortcomings of current portable sensing technologies. Specifically, we have demonstrated the automation and multiplexing capabilities by performing simultaneous automated assays for multiple toxins in the same water sample with a degree of sensitivity and specificity only currently achievable with laboratory based instruments. High detection sensitivity is particularly important because most toxins have sub-ppb level of regulatory requirements for limits of detection. Compared with traditional laboratory based methods, our portable diagnostic platform for environmental monitoring offers several important advantages including reduction in time and cost, real-time data for better and more timely decision making, and reduction in reagent consumption. In the Phase I feasibility study, we have adapted conventional enzyme linked immunosorbent assay (ELISA) procedures to our microfluidic multiplexing automation format for analyzing multiple target antigens from a single sample. Microfluidic automation of ELISA is achieved with our novel microfluidic device, consisting of microvalves and micropumps that can precisely control the delivery and the flow of sample and reagents. Specifically for the Phase I effort, we addressed three key issues: 1) fabrication of microfluidic devices with multiplexing capability, 2) development of an ELISA platform for the target antigens that is suitable for the microfluidic automation format, and 3) development of a detection platform that is suitable for microfluidic multiplexing ELISA. The key technical result of this SBIR Phase I effort is the successful demonstration of the ability of the automated microfluidic multiplexing ELISA platform to 1) quantify the sub-ppb concentrations for cylindrospermopsin and saxitoxin, two common cyanobacteria toxins, in the same sample with a detection limit of 0.05 ppb, 2) exhibit negligible cross-talk between the target toxin detections, and 3) have quantitative results that are comparable to those of manually prepared commercial ELISA kits.
