Development of a methacrylate-terminated PLGA copolymer for potential use in craniomaxillofacial fracture plates

• A new high molecular weight methacrylate-terminated PLGA copolymer has been synthesised.
• The flexural modulus of the new methacrylate-terminated PLGA is maintained at a level comparable with mandibular bone over a six week period in PBS.
• The methacrylate-terminated PLGA behaves similarly to a clinically applied PLGA in mechanical and cytocompatibility tests.

We synthesised methacrylate-terminated PLGA (HT-PLGA, 85:15 LA:GA, 169 kDa), for potential use as an adhesively attached craniomaxillofacial fracture fixation plate. The in vitro degradation of molecular weight, pH and flexural modulus were measured over 6 weeks storage in PBS at 37 °C, with commercially available high (225 kDa, H-PLGA) and low (116 kDa, L-PLGA) molecular weight 85:15 PLGAs used as comparators. Molecular weights of the materials reduced over 6 weeks, HT-PLGA by 48%, H-PLGA by 23% and L-PLGA by 81%. HT-PLGA and H-PLGA exhibited a near constant pH (7.35) and had average flexural moduli in excess of 6 GPa when produced, similar to that of the mandible. After 1 week storage both exhibited a significant reduction in average modulus, however, from weeks 1–6 no further significant changes were observed, the average modulus never dropped significantly below 5.5 GPa. In contrast, the L-PLGA caused a pH drop to below 7.3 by week 6 and an average modulus drop to 0.6 from an initial 4.6 GPa. Cell culture using rat bone marrow stromal cells, revealed all materials were cytocompatible and exhibited no osteogenic potential. We conclude that our functionalised PLGA retains mechanical properties which are suitable for use in craniofacial fixation plates.