Electrochemistry, biosensors and microfluidics are popular research topics that have attracted widespread attention from chemists, biologists, physicists, and engineers. Here, we introduce the basic concepts and recent histories of electrochemistry, biosensors, and microfluidics, and describe how they are combining to form new application-areas, including so-called "point-of-care" systems in which measurements traditionally performed in a laboratory are moved into the field. We propose that this review can serve both as a useful starting-point for researchers who are new to these topics, as well as being a compendium of the current state-of-the art for experts in these evolving areas.

Portable digital microfluidic serological immunoassays for measles and rubella were developed and evaluated in a remote setting.

In low-resource settings, resilience to infectious disease outbreaks can be hindered by limited access to diagnostic tests. Here we report the results of double-blinded studies of the performance of paper-based diagnostic tests for the Zika and chikungunya viruses in a field setting in Latin America. The tests involved a cell-free expression system relying on isothermal amplification and toehold-switch reactions, a purpose-built portable reader and onboard software for computer vision-enabled image analysis. In patients suspected of infection, the accuracies and sensitivities of the tests for the Zika and chikungunya viruses were, respectively, 98.5% (95% confidence interval, 96.2–99.6%, 268 serum samples) and 98.5% (95% confidence interval, 91.7–100%, 65 serum samples) and approximately 2 aM and 5 fM (both concentrations are within clinically relevant ranges). The analytical specificities and sensitivities of the tests for cultured samples of the viruses were equivalent to those of the real-time quantitative PCR. Cell-free synthetic biology tools and companion hardware can provide de-centralized, high-capacity and low-cost diagnostics for use in low-resource settings.