PLGA bone plates reinforced with crosslinked PPF

In this study a matrix of poly(propylene fumarate) (PPF) was crosslinked with N-vinylpyrrolidone (NVP), 2-hydroxyethylmethacrylate (HEMA), or a mixture of NVP and ethyleneglycol dimethacrylate (EGDMA) in the presence of poly(lactide-co-glycolide) (PLGA) to reinforce and preserve the form of PLGA bone plates. The degree of crosslinkage varied depending on the crosslinker as shown by the rapid and almost complete leaching of NVP upon incubation in phosphate buffered saline at 37 degrees C in 900 h and retention of 92% of HEMA. With the reinforced bone plates extracted for 72 h at room temperature methylene chloride, the extracted PLGA from NVP/PPF, NVP-EGDMA/PPF, and HEMA/PPF were 75.42% (w/w), 59.52% (w/w), and 30.86% (w/w), respectively. The flexural modulus and compressive strength of the crosslinked PPF reinforced bone plates were higher than that of the unreinforced bone plate. Atomic force microscopy showed that NVP/PPF reinforced PLGA bone plates eroded substantially (a mean surface roughness of 19.319 nm) whereas NVP-EGDMA-PPF reinforced bone plate showed a distinct crystalline organization (and a higher roughness, 43.525 nm). In conclusion, we propose the consideration of NVP-EGDMA/PPF reinforced PLGA as a biodegradable orthopedic implant material that has a lower likelihood of warping or failing catastrophically than the currently available materials.