Drug and gene delivery system using functional polymers

Abstract

Cancer therapeutics has been investigated vigorously in bio-medical field as life span of human ex-tends. The conventional strategies for drug development in finding excellent synthetic drugs have been changed into the method for smart delivery of an efficient drug. In that sense, stimuli-responsive polymer and nucleic acid drugs are exploited. Here, I suggest two kinds of drug delivery system: thermal responsive drug release with poly(N-isopropylacrylamide) coated surface and dextran conjugated siRNA for high serum stability and efficient gene silencing. Stimuli-sensitive polymer coatings of nanoporous materials have attracted increasing attention for controlled mass transport applications. However, most of the available techniques are based on surface-initiated polymerization that requires additional treatments for surface pre-activation. Here we report a facile one-step method to coat the pore surface of an anodized aluminum oxide (AAO) membrane with a pre-synthesized functional polymer. Monodisperse poly(N-isoproylacrylamide) (PNIPAAm) with a molecular weight of 12 kDa is synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, followed by the conjugation of catechol, a mussel-derived adhesive molecule, to one chain end of the synthe-sized PNIPAAm. The catechol-conjugated PNIPAAm is successfully grafted to the surface of nanopores by infiltration of polymer solution through a porous alumina membrane. The temperature-controlled conforma-tional transition of the grafted PNIPAAm chain is correlated to the variations of contact angle and topography of the membrane surface. Our results show that the hindered diffusivity of dextran (40 kDa) through the 20-nm pores is determined by the surface wettability rather than the pore size. We expect that this simple coating approach can be extended as a general method for other polymer coatings to modify the surface of various nanostructured materials. Small interfering RNA (siRNA) has been...