Dual-functional anti-adhesion barrier prepared using micro-hierarchical structured and neutralized shellac films for drug release.

Micro-hierarchical structured shellac films were prepared using a solution casting method with dodecyltrichloro-immobilized shellac microparticles. We evaluated two opposite surfaces of the shellac films-one a micro-hierarchical structured side and the other a neutralized shellac side using alkali ethanol-for their applications in the medical field. A bending strength test using a tensile strength testing machine and measurement of surface hardness using a scratch hardness tester indicated that the optimal composition of the base films comprised 15% shellac and 10% calcium phosphate as durability promoting agents. Further, dodecyltrichloro-immobilized shellac microparticles were synthesized and spray-deposited on the films. The solubility of shellac increased as the pH of the shellac solution increased. Analyses of cell adhesion, proliferation, and anti-thrombus efficiency were performed using a WST assay, field emission scanning electron microscope, and hemocytometer. The contact angle with the micro-hierarchical structure surface was approximately 150°. The spray-deposited shellac film yielded a lower cell and platelet adhesion rate (20%) than the untreated film. These results indicate that the micro-hierarchical structure has unique properties and that this novel superhydrophobic biodegradable shellac film can be applied as a blood/tissue-compatible, biodegradable material for implantable medical devices that need an anti-adhesion barrier.