A nanoporous biodegradable polymer (polycaprolactone) is fabricated utilizing a zinc oxide nanotemplate (see figure). Chemical characterization verifies removal of the template, and preliminary tests on the cytotoxicity demonstrate basic bio-compatibility. Diffusion of a model small molecule and a protein are shown to be first and zero order, respectively, indicating these nanoporous membranes may be useful for controlled release of protein-based therapeutics.