DNA-enrichment microfluidic chip for chromatin immunoprecipitation

Chromatin immunoprecipitation (ChIP) is a powerful and widely applied technique for detecting association of individual proteins with specific genomic regions; the technique requires several complex steps and is tedious. In this paper, we develop a microbead-packed microfluidic chip which eliminates most of the laborious, timeconsuming, and skill-dependent processes of the ChIP procedure. A computational fluid dynamics model was established to analyze fluidic behavior in a microbeadpacked microchannel. With the use of the new chip, a ChIP procedure was performed to purify the GAPDH (glyceraldehyde 3-phosphate dehydrogenase) gene from human embryonic kidney cells (cell line 293). The ChIP capability of the microfluidic chip was evaluated and compared with that of a commercial assay kit; the precipitation performance of both methods was almost identical as shown by quantitative measurement of DNA. However, our chip offers the advantage of low resin volume, and the experimental time is greatly reduced. In addition, our method is less dependent on individual technical skill. Therefore, we expect that our microfluidic chip-based ChIP method will be widely used in DNA-, gene-, and protein-related research and will improve experimental efficiency.