Currently coronary stent coating materials focus on biodegradable polymers requiring excellent performances, including biodegradability, cytocompatibility and hemocompatibility as well as ductility. To endow poly(l-lactide) (PLLA) with good ductility as stent coating, two kinds of high branched PLLA grafted copolymers with introduction of biobased poly(β-myrcene) rubber segments were developed towards sent coating. The impacts of topological architectures (including linear comb and star comb) on physical properties, hydrolytic and enzymatic degradation behaviors, cytocompatibility, hemocompatibility and coating morphology were investigated. It was found that the nonbiodegradable poly(β-myrcene) rubber segments delayed the degradation rate, and further decreased with more complex architectures. Proteinase K accelerated enzymatic degradation compared with hydrolytic degradation. Biocompatibility testing showed that the fully biobased thermoplastic elastomers possessed good cytocompatibility and hemocompatibility. Morphological characterization of stent coatings indicated that the linear comb and star comb PLLA grafted copolymers improved the surface smooth of pure PLLA coating. Thus, these highly branched fully biobased thermoplastic elastomers are promising to as potential coating materials in drug eluting stent.

当前，冠状动脉支架涂层材料集中于需要优异性能的生物可降解聚合物，包括生物可降解性，细胞相容性和血液相容性以及延展性。为了赋予具有良好延展性的聚（l-丙交酯）（PLLA）作为支架涂层，开发了两种引入生物基聚（β-月桂烯）橡胶链段的高支链PLLA接枝共聚物，以用于成品涂层。研究了拓扑结构（包括线性梳和星形梳）对物理性能，水解和酶促降解行为，细胞相容性，血液相容性和涂层形态的影响。发现不可生物降解的聚（β-月桂烯）橡胶链段延迟了降解速率，并且随着更复杂的结构而进一步降低。蛋白酶与水解降解相比，钾加速了酶的降解。生物相容性测试表明，完全生物基的热塑性弹性体具有良好的细胞相容性和血液相容性。支架涂层的形态学表征表明，线性梳和星形梳PLLA接枝共聚物改善了纯PLLA涂层的表面光滑度。因此，这些高度支化的全生物基热塑性弹性体有望用作药物洗脱支架中的潜在涂料。