World-to-chip interconnects for efficient loading of genomic DNA into microfluidic channels

Abstract

A novel sloped interconnect for the efficient delivery of long genomic DNA fragments into a microfluidic channel is designed, fabricated and tested. Out-of-plane slopes are fabricated in silicon wafers using the deep reactive-ion etch lag phenomenon and a combination of anisotropic and isotropic etching. The final structure is capped with anodically bonded glass. Based upon a series of etch-lag calibration studies, the interconnect was designed using finite element analysis to provide a channel with flow acceleration properties appropriate to straighten DNA molecules. The efficiency of transit of the 48.5 kb DNA fragments (∼16.5 µm long when fully extended) through the microfluidic device, established using quantitative real-time polymerase chain reaction, is 95 ± 7.3%.