A microfluidic droplet serial dilutor with enhanced mixing

We present the development of an automated microfluidic platform that is capable of creating logarithmic serial dilution by adapting pneumatically actuated microvalves. A valve-assisted droplet manipulator integrated with a peristaltic mixer allowed the accurate formation of droplets with controlled sizes and the dilution of reagent sequentially. Hence, serial dilution with flexible dilution factors was obtained in a series of nanoliter-scale droplets. We validated the mixing efficiency and droplet generating performance of the chip at various operating conditions and demonstrated an example of logarithmic serial dilution with two different dilution factors. The microfluidic droplet serial dilutor could be used as an analytical tool to evaluate various complex chemical and biochemical reactions.