An evaporation-based microfluidic sample concentration method

We present a method for sample concentration within microfluidic devices using evaporation-induced flow. Evaporation-induced flow is easy to incorporate into microfluidic designs and can be used to concentrate a wide variety of molecules. The practicality of this method was demonstrated with 0.2 mum fluorescent spheres and FITC- labeled BSA. Thirty two percent of the 0.6 muL fluorescent sphere suspension was concentrated into a well within a microfluidic device. In the same amount of time, 93% of the 0.6 muL FITC- labeled BSA solution was concentrated.