Evaporation-driven microfluidic sample concentration

A new method for sample concentration within microfluidic devices is presented. Evaporation at an air/liquid interface is used to induce flow. within a microfluidic device and concentrate sample. The practicality of this method was demonstrated with 0.2 /spl mu/m fluorescent microspheres and FITC-labeled bovine serum albumin (BSA). Eighty one percent of a 0.6 /spl mu/L fluorescent sphere suspension was concentrated into a well within a microfluidic device. In the same amount of time, 93% of a 0.6 /spl mu/L FITC-labeled BSA solution was concentrated.