Synthesis and Antiplatelet Adhesion Behavior of a Poly(L-lactide-co-glycolide)–Poly(1,5-dioxepan-2-one) Multiblock Copolymer

[Image: see text] Platelet adhesion and denaturation on artificial medical implants induce thrombus formation. In this study, bioabsorbable copolymers composed of poly(l-lactide-co-glycolide) (PLGA) and poly(1,5-dioxepan-2-one) (PDXO) were synthesized and evaluated for their antiplatelet adhesive properties. The PLGA–PXO multiblock copolymer (PLGA–PDXO MBC) and its random copolymer (PLGA–PDXO RC) showed effective antiplatelet adhesive properties, and the number of adhered platelets was similar to those adhered on poly(2-methoxyethylacrylate), a known antiplatelet adhesive polymer, although a large number of denatured platelets were observed on a PLGA–poly(ε-caprolactone) multiblock copolymer (PLGA–PCL MBC). Using monoclonal antifibrinogen IgG antibodies, we also found that both αC and γ-chains, the binding sites of fibrinogen for platelets, were less exposed on the PLGA–PDXO MBC surface compared to PLGA–PCL MBC. Furthermore, free-standing films of PLGA–PDXO MBC were prepared by casting the polymer solution on glass plates and showed good tensile properties and slow hydrolytic degradation in phosphate-buffered saline (pH = 7.4). We expect that the unique properties of PLGA–PDXO MBC, i.e., antiplatelet adhesive behavior, good tensile strength, and hydrolytic degradation, will pave the way for the development of new bioabsorbable implanting materials suitable for application at blood-contacting sites.