Multifunctional 3D sponge-like macroporous cryogel-modified long carbon fiber reinforced polyetheretherketone implants with enhanced vascularization and osseointegration.

Long carbon fiber reinforced polyetheretherketone (LCFRPEEK), a newly developed high-performance composite material, is being investigated as a possible orthopedic implant. However, its inability of angiogenesis and osseointegration after implantation makes it difficult for use as a long-term osteogenic fixation implant, which limits its scope of clinical application. Therefore, we design and construct a multifunctional 3D sponge-like macroporous cryogel to modify sulfonated LCFRPEEK using a cryogelation method based on free radical photopolymerization. The cryogel is mainly composed of graphene oxide-hydroxyapatite (GO-HAP) nanocomposites and gelatin methacrylate/polyethylene glycol diacrylate (GelMA/PEGDA). The results reveal that the multifunctional LCFRPEEK implant shows excellent biocompatibility and osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs) due to the incorporation of HAP nanoparticles into GO-HAP nanocomposites. Systematic animal studies further confirm that the multifunctional surface improves the bone remodeling and osseointegration of the LCFRPEEK implant. Additionally, the characteristic 3D sponge-like macroporous structures of cryogels promote the ingrowth and migration of human umbilical vein endothelial cells (HUVECs) and GO in the GO-HAP also boosts HUVEC migration and tube formation showing that they are beneficial for vascularization during osteogenesis. Therefore, the developed 3D sponge-like macroporous GelMA/PEGDA/GO-HAP cryogel fabricated on sulfonated LCFRPEEK implants with enhanced angiogenesis and osseointegration capabilities has great potential for clinical use as an orthopedic implant material.