Functionalization of gold surfaces with copoly(DMA-NAS-MAPS) by dip coating: Surface characterization and hybridization tests

In this work, a new method to functionalize a gold surface by dip coating with a functional copolymer is presented. The coating procedure is simple, robust and can be accomplished in less than one hour. Atomic force microscopy (AFM) scratch tests reveal the presence of a homogeneous polymer coating with a thickness of 2.5 nm. X-ray photoemission spectroscopy spectra from C1s, N1s and O1s levels present the typical fingerprints of the polymeric overlayer, i.e. the characteristic peaks from CNCO and NCO groups. Surface plasmon resonance (SPR) binding assays were used to check the coating functional properties. Immobilization of heparin to SPR gold surfaces functionalized with copoly(DMA-NAS-MAPS)- followed by binding analysis with the well known heparin binding protein fibroblast growth factor 2 yield binding kinetic parameters comparable to those obtained with commercially available carboxymethyl dextran-functionalized sensorchips, thus confirming the great potential of the proposed technique.