Microfluidic chips for DNA amplification, electrophoresis separation and on-line optical detection

This paper reports at innovative microfluidic chip capable of performing DNA amplification (polymerase chain reaction, PCR), electrokinetic sample injection and separation, and on-line optical detection of DNA. All microfluidic modules are integrated on cheap and biocompatible soda-lime glass substrates using a simple and reliable fabrication process. With this approach, DNA samples could be first duplicated using the micro PCR module, then injected and separated in the micro electrophoretic channels driven by electrokinetic forces, and finally detected optically by buried optical waveguides downstream the separation channel. In order to have a better separation efficiency for DNA samples, a novel surface treatment method by coating a thin layer of spin-on-glass (SOG) is developed. Experimental data show that DNA samples can be successfully duplicated using the micro PCR device with less sample and reagent volumes in a shorter period thanks to lower thermal inertia of the micro devices. DNA samples can be injected, separated and detected successfully in the subsequent microfluidic channels. The integrated microfluidic device could be crucial for genetic analysis.