Direct detection of DNA with an integrated detector on a microfluidic chip

Abstract

A microfluidic chip has been developed which allows for the direct detection of several distinct DNA targets present in a sample. The direct detection of underivatized DNA is advantageous for the analysis of very small amounts of sample, where contamination is a major concern. DNA probes can be attached in microchannels present on the chip via a biotin/avidin linkage. The sample is then introduced into the channel where an appropriate DNA target hybridizes with its complementary probe. Following hybridization of the target, an alkaline buffer is introduced to the channel to dehybridize the double-stranded DNA and flush the target downstream to a copper electrode. The dehybridized DNA is then detected electrochemically. The elution time can be used to identify the particular DNA target since the DNA probes are spatially segregated in the channel. Integrating the detector and the sensing probes on the microfluidic chip allows for an inexpensive and easily fabricated biosensor device for the precise recognition and subsequent detection of a specific complimentary DNA target for diagnosis and genetic screening.