A mobile electrochemical detector called uMED can test for a variety of molecular-level health or environmental indicators and then use any cell phone on any cellular network to transmit results for remote analysis and diagnosis. The device, which costs about $25, could give people in resource-limited areas the ability to perform tests typically carried out by expensive laboratory electrochemical instruments.
Developed by George M. Whitesides of Harvard University and coworkers, uMED is based on a simple blood glucose monitor (Proc. Natl. Acad. Sci. USA 2014, DOI: 10.1073/pnas.1405679111). The device mixes samples by vibration and uses test strips or electrodes together with a potentiostat to analyze them by any of several electrochemical methods: chronoamperometry, cyclic voltammetry, differential pulse voltammetry, square wave voltammetry, or potentiometry.
Using a cell phone’s headphone jack and voice channel, uMED uploads sample data to a data management network. This voice-based data transfer approach ensures that the device is compatible with any mobile phone and with cellular networks from 2G to 4G. The network records and analyzes the data, and results and advice are returned to the user via text message to the same phone.
The researchers note that in most cases previous mobile reporting and point-of-care diagnostic systems required users to enter data by hand, were more limited functionally and lacked network connectivity, or required sophisticated equipment and technologies available primarily in developed countries.
The team demonstrated uMED by using it to detect trace amounts of toxic heavy metals in drinking water, measure glucose in blood, monitor sodium in urine, and perform an electrochemical enzyme-linked immunosorbent assay for malaria antigen.
The study implements “a couple of clever ideas, including the vibration mechanism for on-board sample mixing and the audio jack as a universal communication mechanism,” comments biomedical engineer Samuel K. Sia of Columbia University. “Further work would involve deploying the device in a field setting to gather data and user feedback.”