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.