Optimization of the bio-functionalized area of magnetic biosensors

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 2.5nm. 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 CNC   O and NC   O 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.