Rapid, Affordable, Point-of-Use Microfluidic Sensors for Water Monitoring for Global Health
The difficulty of detecting small quantities of arsenic and other contaminants in water currently threatens the health of millions of people worldwide, as long-term exposure to arsenic has been associated with both cancerous and noncancerous health risks. Existing technologies make it possible to very accurately quantify arsenic levels in water; however the expense, extensive training, and off-site analysis required by these methods impede wide scale-use.
To overcome these limitations, we have developed an integrated system combining a microfluidic sensor, data acquisition mobile app, and web-based data logging ecosystem, which allows for quick, easy, error proof evaluation of water sources for a variety of contaminants. Our microfluidic sensor employs a three-electrode system onto a polymer substrate, providing a rigid and durable platform that remains cost-effective and disposable. Considering that the communities that need these sensors the most lack internet access and the ability (personnel and equipment) to analyze the data obtained by the sensor locally, we have adapted the sensor to a mobile device, e.g., a cellular telephone, to enable the instant interpretation of the data obtained and the mapping of the test results from different places, indicating safe vs. not-safe water sources. This aspect of our platform could resolve the issues associated with the lack of trained personnel, which is a major and severe constraint in deploying health technology in these resource-limited regions.
Paper-based Microfluidic Devices towards Affordable, Equipment-free, and Specific Detection of Pathogens
The development of affordable, equipment-free, fast, and accurate pathogen detection methods is essential to many field applications including food and environmental monitoring, as well as diagnostics. Most current pathogen detection methods are not suitable for resource limited settings because an accurate result is dependent on special equipment or reagents, specialized training, extended time periods, electricity or cold storage, or sterile environments not feasible outside of a laboratory. To satisfy these unmet needs, we have developed a paper-based sensor detecting a specific target sequence of oligonucleotide on a functionalized cellulose surface. The entirety of the assay is performed on a piece of paper and requires no external instrumentation or electricity. The broad applications of this detection method as simple, portable, rapid and specific diagnostics were exemplified by the detection of E. coli target oligonucleotide.
Monolithic, Low-power Micropump towards Integrated Microfluidic Systems
While the most common way to drive microfluidic flow is via syringe pumps attached to tubing onto a chip, these pumps are quite bulky, expensive, and not ideal for miniaturization and integration with other microfluidic components, especially for point-of-care diagnostic applications. To overcome these limitations, we have developed an electrolytic micropump integrating a pump, check valves, and chambers within a single layered platform, which allows facile integration with other microfluidic systems. Our micropump combines electrolytic bubble growth, catalyst-driven recombination of electrolysis gasses and passive check-valves to cyclically dispense fluids.