Study On Surface Mineralization Of AG-Nano-Hydroxyapatite/Polyamide66Porous Scaffold

Objective:Bacterial infection after implantation of bone tissue engineering scaffolds is still a serious clinical problem. This study was to fabricate a novel surface mineralized Ag-nano-hydroxyapatite (Ag-nHA)/polyamide66(PA66) antibacterial composite scaffold and to investigate the release behaviors of Ag+and antibacterial properties of mineralized scaffold.Methods:Ag-nHA/PA66porous scaffolds were prepared by thermal-induced phase inversion method. The scaffolds were cut into cubes (6×6×6mm3) and mineralized in saturated calcium phosphate solution at37℃for24h. The micro structure and the newly formed nano-apatite deposition on the scaffolds before and after mineralization were observed using scanning electron microscopy (SEM). In order to investigate the release behaviors of Ag+, the Ag-nHA/PA66scaffolds before and after mineralization were immersed into5ml PBS at37℃for a period of3h to168h. Moreover, the samples were cultured with E.coli (8099) to test the antibacterial effect of the scaffolds. Results:The results show that, after mineralization, Ag-nHA/PA66porous scaffolds still exhibit well inter-connective and a new apatite layer is formed on the surface of the scaffolds. The average macro pore size is626.61±141.94μm. The porosity is76.89±8.21%and the compressive strength is2.94±1.12MPa. All these physical parameters have no significant difference from the un-mineralized scaffolds. The Ag+release of the scaffolds with and without mineralization is fast within1d and then keeps slow and stable after1d. The antibacterial test confirms the scaffolds after mineralization have good antibacterial effects on E.coli.Conclusion: After the mineralization, a plate-like nano-apatite is formed on the surface of Ag-nHA/PA66porous scaffolds, but the physical parameters (porosity, average macropore size and compressive strength) have no significant difference from the un-mineralized scaffolds. The Ag+can be released slowly, and it keeps good antibacterial ability. Ag-nHA/PA66is an ideal antibacterial composite for the bone repair and regeneration.