Research On Preparation And Properties Of Polymer Composite Scaffolds Based On Laser Additive Manufacturing Technology

Large-scale bone defects caused by trauma,infection,tumor and other factors are often difficult to heal by their own ability,and good bone tissue substitutes are needed to help repair,which makes artificial bone scaffolds attract much attention.Polymer materials have good biocompatibility and natural degradability,which are widely used as matrix materials of bone scaffold.But their insufficient mechanical properties,lack of antibacterial properties,and poor biological activity limit their further applications.Therefore,this paper proposed a selective laser sintering(SLS)technique to fabricate composite scaffolds,using zinc oxide(ZnO)nanoparticles as reinforcing phase and nucleating agent to improve the crystallinity of polymers,thereby improving the compressive properties of polymer bone scaffolds;In addition,in situ growth of silver(Ag)nanoparticles on ZnO formed Ag@ZnO heterojunctions,and the photocatalytic properties of Ag@ZnO heterojunctions to endow the antibacterial properties of polymer bone scaffolds;In situ growth strontium(Sr)nanoparticles on reduced graphene oxide(r GO),the Sr@r GO co-dispersed structure was formed,and the barrier protection effect of r GO was used to slowly release strontium ions,thereby enhancing the osteogenic activity of the polymer bone scaffold.The main work and innovation results are as follows:1.In view of the problem of insufficient mechanical properties of polymer bone scaffolds,it was proposed that on the one hand,the heterogeneous nucleation effect of ZnO could promote the orderly stacking of polymer chains and accelerate the nucleation of polymers,thereby increasing the crystallinity to enhance the compressive properties of the scaffolds.On the other hand,ZnO acted as a reinforcing phase,which could hinder the propagation and development of cracks,thereby strengthening the compressive strength of the scaffold.2.In view of the lack of antibacterial properties of polymer bone scaffolds,it was proposed in-situ grow Ag on ZnO to form Ag@ZnO heterojunctions.Due to the addition of silver,the forbidden band width of ZnO was narrowed and the surface impedance was reduced,so that the electrons of ZnO were transferred to the surface of silver,preventing the recombination of electron and hole pairs of ZnO,thereby improving the photocatalytic effect of zinc oxide to generate ROS efficiency,which in turn endowed the composite scaffold with antibacterial properties.3.In view of the low biological activity of polymer bone scaffolds,it was proposed to in-situ grow Sr on reduced graphene oxide to form co-dispersed structure,and further composited it with polymers to prepare a scaffold.The effects of Sr@r GO co-dispersed structure on cell adhesion,cell fluorescence and osteogenic activity were investigated.