Diffusion-based microfluidic PCR for "one-pot" analysis of cells

Genetic analysis starting with cell samples often requires multi-step processing including cell lysis, DNA purification, and polymerase chain reaction (PCR) based assays. When conducted on a microfluidic platform, the compatibility among various steps often demands complicated procedure. Here we present a microfluidic device that permits "one-pot" strategy for multi-step PCR analysis starting from cells. Taking advantage of the diffusivity difference, we replace the smaller molecules in the reaction chamber by diffusion while retaining DNA molecules inside. This simple scheme effectively removes reagents from the previous step to avoid interference and thus permits multi-step processing in the same reaction chamber.