Synergistic enhancement of toughness and biocompatibility in poly(l-lactide) via copolymerization with poly(ε-caprolactone) and multi-arm branched strategy for aortic stent applications

Poly(lactide) has demonstrated significant potential in small-diameter vascular stents, particularly in coronary artery applications. However, its limited toughness and suboptimal biocompatibility hinder its use in high-stress regions such as the aorta. To overcome these limitations, we have designed and synthesized multi-arm poly(l-lactide-b-ε-caprolactone) (PLCL) copolymers with enhanced toughness and biocompatibility through copolymerization with polycaprolactone and multi-arm branching strategies. This study comprehensively evaluates the chemical structure, crystallization properties, mechanical properties, adhesion properties, biocompatibility and in vivo degradation profiles of multi-armed PLCLs. Results show that PLCLs exhibit substantial tensile strength and toughness, with tensile strength ranging from 1.43 MPa (2a-PLCL) to 42.45 MPa (6a-PLCL), and elongation at break from 3.07 % (2a-PLCL) to 31.49 % (6a-PLCL). Both of them were positively correlated with the number of arms. In vitro studies revealed enhanced cell adhesion and proliferation for multi-armed PLCLs. Animal model evaluations confirmed excellent histocompatibility and as the number of polymer arms increased, inflammation decreased, and the degradation rate accelerated. Notably, the 6a-PLCL exhibited the best overall performance, making it more favorable for promoting aortic remodeling. In summary, this study suggests that multi-armed PLCLs are promising candidates for cardiovascular tissue engineering and absorbable medical devices due to their enhanced mechanical properties and biocompatibility.