Fast DNA Immobilization and Hybridization on a CD (Compact Disc) Microfluidic Platform

In this study, we report a method to enhance the adsorption rate of thiolated single-stranded DNA (ssDNA) on gold surfaces using a compact disc (CD)-based flowthrough approach. A multi-level SU-8 lithography process was used to fabricate a two-level mold for replication of polydimethylsiloxane (PDMS) flow cells. Various concentrations of thiolated, Cy3-labeled 25-mer capture probes (5µM, 2.5µM, 1µM) were immobilized in a flow through column using either the flow-through protocol or standard passive diffusion limited procedures. Fluorescence measurements were used to test the relative efficiencies of the flow vs. passive immobilization methods. Compared to passive incubation, the adsorption rate from the flowthrough method was up to 2.5-fold higher given the same immobilization time. In addition, the ability of the probes that were immobilized with the flow-through protocol to hybridize with their compliment was verified.