| Large-scale bone defects in craniofacial region caused by various reasons are difficult to heal themselves,and the most common bone transplantation methods in clinic,such as autologous or allogeneic bone transplantation,have inevitable drawbacks.In order to restore the shape and function of damaged areas as soon as possible,bone tissue engineering scaffolds have a promising application prospect.Among them,the porous scaffold obtained by 3D printing technology has regular shape,uniform pores and interconnected,and has outstanding ability as a tissue engineering bone repair material.In recent years,β-tricalcium phosphate(β-TCP)has become one of the most commonly used basic materials for 3D printing.Its good biocompatibility and bone conductivity make it widely used.Polyvinyl alcohol(PVA),as a water-soluble polymer material,has its viscoelasticity and biological safety,which makes it an excellent partner suitable for compounding with β-TCP to make scaffold materials.Considering the lack of osteoinductive components,icariin(ICA),a traditional Chinese medicine component,was selected to be added to the scaffold material because of its mechanism of promoting bone formation and inhibiting bone resorption similar to estrogen.Therefore,in this study,polyvinyl alcohol/β-tricalcium phosphate composite scaffold loaded with icariin(PVA/β-TCP/ICA)is prepared by3 D printing,and the potential of this scaffold to repair craniofacial bone defects is evaluated through a series of physical characterization and biological experiments.1.First of all,PVA/TCP/ICA scaffold(PTI)was successfully prepared by 3D printing,and PVA/TCP scaffold(PT)was also prepared as a control group without any drugs.Macro and micro observation results show that the colors of the two groups of scaffolds are different,PT is white as a whole,and PTI is light yellow as a whole due to the addition of ICA.In shape,the two groups of scaffolds have a three-dimensional structure with regular shape,and both have a high number of uniform and interconnected macropores.The incorporation of drugs has no effect on the pore size and porosity of scaffolds under electron microscope.Microporous structure can be seen on the surface of both groups of scaffolds,but PTI is more obvious than PT in surface roughness.The experiments of mechanical properties and water contact angle show that the strength of the scaffold is weakened to some extent after drug loading,but a good hydrophilic-hydrophobic balance is achieved,which is beneficial to cell adhesion.Through 80 days of testing,PTI drug release has been proved to be long-acting and controllable.It will not cause cytotoxicity due to excessive concentration caused by ICA release in a short time,but can continuously promote cell proliferation and differentiation.2.Then,the biocompatibility of the two groups of scaffolds was evaluated by the detection of cytotoxicity,cell adhesion and cell proliferation.Both PTI and PT have no cytotoxic effect,but PTI is superior to PT in terms of cell adhesion and cell proliferation promotion.At this time,the advantages of PTI have begun to appear.In addition,the test results of alkaline phosphatase(ALP)activity show that PTI has a significantly higher effect on promoting osteogenic differentiation than PT.From various cell biology experiments,PTI has certain safety and osteogenic effect as a tissue engineering bone repair material.3.Finally,the osteogenic effect of PTI in vivo was detected by rat skull defect model.Combined with the results of gross specimens,micro-CT and tissue sections,the skull defects of rats in PTI group were mineralized from the 4th week to the 12 th week,and the obvious mature bone tissue was repaired,and the effect was better than that of PT group.The results of zoological experiments directly confirmed the osteogenic performance of PTI.This series of research results have confirmed that the addition of icariin improves the osteogenesis effect,and PVA/β-TCP/ICA composite scaffold may become a potential biomaterial in the field of craniofacial bone defect repair. |
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