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

ABSTRACT 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.