Micro-imprinting of oligonucleotides and oligonucleotide gradients on gold surfaces: A new approach based on the combination of scanning electrochemical microscopy and surface plasmon resonance imaging (SECM/SPR-i)

A new strategy for the formation of DNA patterns on thin gold surfaces together with DNA hybridization is described. The formation and characterization of the oligonucleotide array is based on a combination of an electrochemical and an optical technique: scanning electrochemical microscopy and surface plasmon resonance imaging (SECM/SPR-i). The DNA array is formed through electropolymerization of a mixture of pyrrole and pyrrole bearing covalently linked oligonucleotides probes using SECM. SPR-i as well as fluorescence imaging are used to quantify DNA hybridization on these multi-parametric interfaces. The capability of scanning electrochemical microscopy (SECM) to pattern gold surfaces with density gradients of oligonucleotides attached to the gold surfaces is further demonstrated. These density gradients result from the progressive increase in the movement of the x-axis while applying continuous potential pulses to the gold surface. Surface plasmon resonance imaging is used to detect the deposition step, while fluorescence imaging is employed to visualize the deposited oligonucleotide density gradient.