Biofunctional oligoN-isopropylacrylamide brushes on silicon wafer surface

In this study, we report a surface-initiated nitroxide-mediated polymerization (NMP) of N -isopropylacrylamide in the presence of cysteamine (CA) chain transfer agent to fabricate oligo N -isopropylacrylamide (oligoNIPAM) brushes with amine end-groups. The resulting oligomeric brushes were characterized by ellipsometry, grazing angle-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and a contact-angle goniometer to identify the film thickness, surface composition, surface morphology and water contact angles. The oligoNIPAM brushes were then functionalized with biotin units in order to provide selective attachment points for streptavidin proteins. Fluorescence spectroscopy confirmed the successful immobilization of streptavidin molecules on the oligoNIPAM brushes. Finally, it is demonstrated that this fabrication method allows the selective immobilization of streptavidin molecules to brush structures functionalized with biotin units. Oligo( N -isopropylacrylamide) (oligoNIPAM) brushes with an amine end-group were fabricated through a novel and reliable strategy by a combination of the self-assembly of a monolayer of bimolecular macroazoinitiator and surface-initiated NMP in the presence of cysteamine chain transfer agent.