Pore-Filling Nanoporous Templates from Degradable Block Copolymers for Nanoscale Drug Delivery

Nanoporous thin-film samples, fabricated from degradable block copolymers, polystyrene-b-poly(l-lactide) (PS-PLLA), were utilized as templates for the formation of ordered nanoarrays. This work elucidates the feasibility of using such nanoporous PS templates as coatings on implantable devices for drug delivery through pore-filling sirolimus. Specific pore-filling process was adopted to increase loading efficiency by exploiting the capillary force associated with the tunable wetting property of the sirolimus solution. After the pore-filling process, sirolimus-loaded cylindrical and lamellar nanoarrays can be obtained. A comparison with those of macroscale templates indicates that the developed nanoporous templates can successfully entrap the loaded drug in nanoscale pores, markedly increasing the duration of drug delivery. As a result, the size, geometry, and depth of the nanoscale pores of the nanoporous templates can be readily controlled to regulate the drug release profiles.