Tailored Biodegradable Copolymers With Random-Block Architecture for High-Performance Absorbable Tissue Ligation Clips.

To address the balance between mechanical strength and flexibility in absorbable tissue ligation clips, a novel copolymer poly(L-lactide-r-ε-caprolactone)-b-poly(L-lactide) (PLCL-b-PLLA) with random-block molecular architecture is developed by integrating the flexibility of PLCL random copolymer and the high strength of PLLA homopolymer. Three random-block copolymers with different LLA/CL ratios are designed and synthesized. Among them, the copolymer with an LLA/CL ratio of 75:25 (PLC75-RB) exhibits the most balanced overall performance. The PLC75-RB copolymer is injected into Hem-o-lok-shaped clips (CLIP75-RB), and the CLIP75-RB possesses sufficient closure force and favorable rebound ability, meeting the requirements for tissue ligation. The degradation evaluation indicates that the CLIP75-RB maintains effective closure force for up to 4 weeks and then begins to degrade gradually. Further validation in a rabbit unilateral nephrectomy model confirms that CLIP75-RB effectively performs ligation function and subsequently undergoes controlled degradation. The histological analysis demonstrates the good biocompatibility of the clips. The random-block PLCL-b-PLLA copolymers expand the range of biodegradable polymers, and the PLC75-RB exhibits well-matched mechanical performance and degradation behavior, highlighting the potential for the next generation of absorbable tissue ligation clips.