Expanding accessibility of diagnostics through miniaturized technologies

There is a disproportionate burden of disease (measured in daily-adjusted life years, or DALYs) in low-income countries. Much of this disparity is due to infectious diseases: 53% of DALYs in Africa are due to infectious diseases, compared with only 3% in the American continents. This disparity is largely due to differences in electrical and transport infrastructure as well as access to skilled personnel and monetary resources. Current diagnostic solutions are primarily designed for high-resource settings and therefore these solutions cannot be easily translated to a lower-resource setting. In order to tackle this health disparity, new solutions must be designed specifically for a lower-resource setting. In this dissertation, we take a translational approach to engineering appropriate diagnostics for resource-limited settings. First, we develop a handheld smartphone accessory to perform an assay similar to enzyme-linked immunosorbent assay (ELISA), traditionally a laboratory-based test. In 15 minutes, it provides an objective diagnostic readout important for minimal training, while using an average of 1.6mW of power and costing only $34. We further develop the device to provide a quantitative hemoglobin measurement simultaneously with an HIV immunoassay, for use in antenatal care screening. The multiplexing two assay types that are clinically relevant has the potential to streamline workflow. While specifications can be demonstrated in the laboratory, the true test of the device must be performed in the field. We brought our smartphone accessory to three health centers in Kigali, Rwanda to be used by healthcare workers with no prior experience in ELISA. After a short 30 minute training, the healthcare workers were able to obtain diagnostic results comparable to other immunoassays run under field conditions. With a simple and user-friendly design, we sought to further expand the usage of our device as a self-testing device, having patients test themselves. Lastly, we explore manufacturable thermoplastics as a material for a microfluidic diagnostic for nucleic acid detection. The sum of this work aims to gain insight into methods of design, testing, and implementation of translational design.