Fishing DNA targets in DNA solutions by using affinity microcontact printing

Abstract

In this paper, we report the application of affinity microcontact printing (αCP) for “fishing” DNA targets in aqueous solutions and transferring them to solid surfaces for detection purposes. Affinity stamps used in this experiment were made of poly(dimethylsiloxane) (PDMS) with DNA probes covalently immobilized on their surface. When these stamps were immersed in DNA solutions, DNA targets with a perfect-match (PM) sequence to the probes can selectively hybridize to the stamp surfaces and then be transferred to solid surfaces. However, to distinguish PM DNA from single base-pair mismatch (1MM) DNA targets, 10 mM of NaCl must be added to the hybridization buffer. Under the optimized conditions, this αCP can lead to a surface density of PM which is 15 times higher than that of 1MM. The affinity stamp is also able to “fish” PM DNA targets from a mixture of PM/1MM DNA targets and transfer them to solid surfaces. Because DNA probes and targets are separated after printing, we also applied this technique for label-free detection of DNA targets by using liquid crystals.