Multifunctional Biodegradable Vascular PLLA Scaffold with Improved X-ray Opacity, Anti-Inflammation, and Re-Endothelization

Poly(L-lactic acid) (PLLA) has been used as a biodegradable vascular scaffold (BVS) material due to high mechanical property, biodegradability, and biocompatibility. However, acidic byproducts from hydrolysis of PLLA reduce the pH after the surrounding implanted area and cause inflammatory responses. As a result, severe inflammation, thrombosis, and in-stent restenosis can occur after implantation by using BVS. Additionally, polymers such as PLLA could not find on X-ray computed tomography (CT) because of low radiopacity. To this end, here, we fabricated PLLA films as the surface of BVS and divided PLLA films into two coating layers. At the first layer, PLLA film was coated by 2,3,5-triiodobenzoic acid (TIBA) and magnesium hydroxide (MH) with poly(D,L-lactic acid) (PDLLA) for radiopaque and neutralization of acidic environment, respectively. The second layer of coated PLLA films is composed of polydopamine (PDA) and then cystamine (Cys) for the generation of nitric oxide (NO) release, which is needed for suppression of smooth muscle cells (SMCs) and proliferation of endothelial cells (ECs). The characterization of the film surface was conducted via various analyses. Through the surface modification of PLLA films, they have multifunctional abilities to overcome problems of BVS effectively such as X-ray penetrability, inflammation, thrombosis, and neointimal hyperplasia. These results suggest that the modification of biodegradable PLLA using TIBA, MH, PDA, and Cys will have important potential in implant applications.