Mineralization Modification And Its Cellular Responses On Microsphere Scaffold For Bone Repair

Not only porous composite microsphere scaffolds performing good biocompatibility,degradability and controlled delivery,but also HA coatings endowed with favorable osteogenic activity were facilitated in bone tissue engineering.In this paper,based on emulsion solvent evaporation method and low-temperature fusion technique,we successfully fabricated porous PLGA/HA composite microspheres and corresponding scaffolds.Then the construction of mineralized topographies on PLGA/HA composite microsphere scaffolds were made use of low-temperature plasma processes and mineralization in vitro,and the corresponding cellular responses were investigated.Firstly,porous PLGA/HA composite microspheres were prepared by means of emulsion solvent evaporation method and the morphologies of them could be tuned by PLGA concentration and HA content.Then we fabricated corresponding scaffolds using low-temperature fusion technique in which space and air flow could be changed to enhance the compressive strength of scaffolds.Secondly,PLGA/HA composite microsphere scaffolds were processed by oxygen and ammonia plasma treatments which could enhance roughness,hydrophilicity,change the type and content of elements and radicals,decrease zeta potential of microsphere unite surface,and regulate apatite nucleation to a certain degree.Thirdly,diverse mineralized topographies on PLGA/HA composite microsphere scaffold were fabricated by mineralization in vitro and the responses of mouse bone mesenchymal stem cells to them were further studied.The results showed that mineralized layer with high roughness which had pore and bump topographies had more effects on cell attachment,proliferation and differentiation.Finally,we investigated drug delivery release of mineralized PLGA/HA composite microspheres and corresponding scaffolds loading growth factor.The results showed that mineralized layer decreased drug burst release for encapsulation and drug burst release/release rate for absorption.In conclusion,the mineralized topography design on PLGA/HA composite microsphere scaffold can affect stem cell attachment,proliferation,osteogenic differentiation and growth factor delivery release,providing a reference to fabricate multi-functional artificial bone tissue regeneration devices.