Segmental long bone regeneration guided by degradable synthetic polymeric scaffolds

Xiaowen Xu, Jie Song

Table 1 Degradable synthetic polymeric scaffolds for long bone segmental defects

Graft composition Animal Segmental defect Therapeutics Regeneration outcomes Limitations 3D printed PCL/β-TCP composite SheeP44 3 cm tibial 3.5 mg rhBMP-7 Radiographic union; mechanical restoration Slow graft resorption PLGA microparticles SheeP38 2.5 cm femoral 4-mg rhBMP-2 Radiographic union (no mechanical testing) Tendency of PLGA breakage PLGA-coated gelatine sponge Dog39 2.5 cm tibial 0.4 mg/mL rhBMP-2 Radiographic union; mechanical restoration Small sample size; Bone resorption Porous PLA-PEG/HAP Rabbit46 1.5 cm radial 5-20 μg rhBMP-2 Radiographic union (no mechanical testing) Slow graft resorption PLA-DX-PEG/b-TCP Rabbit47 1.5 cm femoral 50 mg rhBMP-2 Radiographic union; mechanical restoration; full graft resorption Graft distortion within defect 3D-printed PELGA/HAP Rat54 5 mm femoral 400 ng rhBMP-2/7 Facile & stable graft fixation; rapid union, full graft resorption & mechanical restoration Larger animal translation unknown Solid PPF rod/porous sleeve with PLGA microparticle Rat60 5 mm femoral 2-8 μg rhBMP-2 Improved defect fixation by solid rod; improved bone formation Regeneration impeded by solid rod; no union Crosslinked PPF/PPF diacrylate with PLGA microparticle Rabbit61 1.5 cm radial 200 μg TP508 Improved osteointegration No union; slow graft resorption Salicylic acid-based poly(anhydride-ester)/PCL membrane Rat65 5 mm femoral 12 μg rhBMP-2 Ectopic bone formation suppressed; long bone regeneration improved (no mechanical testing) Poor graft mechanical property; long-term remodelling unclear Tyrosine-derived polycarbonate/CP Rabbit99 1.5 cm radial 17-35 μg rhBMP-2 Improved bone formation (no mechanical testing) No union pHEMA-HAp composite Rat116 5 mm femoral 400 ng rhBMP-2/7 Radiographic union; mechanical restoration Slow graft resorption MMP-sensitive 4-arm PEG hydrogel with integrin binding GFOGER Murine126 2.5 mm radial 30 ng rhBMP-2 Radiographic union; mechanical restoration; MMP-responsive degradation Potentially high manufacturing cost