Chemical micropatterning of polycarbonate for site-specific peptide immobilization and biomolecular interactions

Polycarbonate (PC) is a useful substrate for the preparation of microfluidic devices. Recently, its utility in bioanalysis has attracted much attention owing to the possibility of using compact discs as platforms for the high-throughput analysis of biomolecular interactions. In this article we report a novel method for the chemical micropatterning of polycarbonate based on the printing of functionalized silica nanoparticles. The semicarbazide groups present on the surface of the nanparticles were used for the site-specific semicarbazone ligation of unprotected peptides derivatized by an alpha-oxoaldehyde group. The peptide micropatterns permitted the specific capture of antibodies. We report also the characterization of micropatterns on PC by using a wide-field optical imaging technique called sarfus; this allows the detection of nm-thick films by using nonreflecting PC substrates and an optical microscope working with reflected differential interference contrast. The method described here is an easy way to modify polycarbonate surfaces for biomolecular interaction studies and should stimulate the use of PC for developing plastic biosensors.