Immobilization of Stimuli-Responsive Nanogels onto Honeycomb Porous Surfaces and Controlled Release of Proteins

In this article, we describe the formation of functional honeycomb like porous surfaces fabricated by the breath figures technique using blends of either amino-terminated poly(styrene) or a poly(styrene)-b-poly(acrylic acid) block copolymer with homopoly(styrene). Thus, the porous interfaces exhibited either amino or acid groups selectively located inside of the holes, which were subsequently employed to anchor stimuli-responsive nanogels by electrostatic interactions. These nanogels were prepared from poly(N-isopropylacrylamide) (PNIPAM) cross-linked with dendritic polyglycerol (dPG) and semi-interpenetrated with either 2-(dimethylamino)ethyl methacrylate (DMAEMA) or 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) to produce positively and negatively charged nanogel surfaces, respectively. The immobilization of these semi-interpenetrated networks onto the surfaces allowed us to have unique stimuli responsive surfaces with both controlled topography and composition. More interestingly, the surfaces exhibited stimuli-responsive behavior by variations on the pH or temperature. Finally, the surfaces were evaluated regarding their capacity to induce a thermally triggered protein release at temperatures above the cloud point temperature (T-cp) of the nanogels.