In vitro study on new bioactive bone screws affecting biological behavior of osteoblasts

Abstract

Objective To detect the effect of a new bioactive bone screws composed of nanohydroxyapatite/polyamid 66/glass fiber (n-HA/PA66/GF) biomaterial on biological behavior of osteoblasts with a view to a later clinical application of the screws.Methods Mice osteoblasts were co-cultured with n-HA/PA66/GF biomaterial or its extract.Cell growth was detected under a microscope,cell proliferation using MTT assay,apoptosis by flow cytometry,osteocalcin by ELISA method,cell migration using Transwell invasion assay,cell adhesion and growth by scanning electron microscope,and cytoskeleton and actin filament distribution using immunofluorescene.Results Direct contact test demonstrated n-HA/PA66/GF material had no obvious cytotoxicity to osteoblasts.Extract of n-HA/PA66/GF material stimulated osteoblast proliferative activity over time with absorbance value of 0.96 ± 0.14,1.54 ± 0.15,and 2.39 ±0.27 respectively after 2,4,and 6 hours of coculture (P ＜ 0.05).The n-HA/PA66/GF material induced more osteoblasts to entering S period without obvious influence on apoptosis rate and promoted osteocalcin secretion.Migrated cells in medium supplied with n-HA/PA66/GF material or FBS was 8.73 ± 3.26 and 9.47 ± 3.29 in each visual field,but there was no significant difference (P ＞ 0.05).Osteoblasts had a regular form on the surface of n-HA/PA66/GF material,closely adhered to the surface,and reproduced and aggregated with each other to form stratified cell layers.However,nHA/PA66/GF material exhibited no obvious influence on distribution of cytoskeleton and actin filament.Conclusion The new n-HA/PA66/GF screws has excellent cytocompatibility with positive regulatory effect on cell growth,proliferation,secretion,adhesion,cycle,and osteocalcin secretion. Key words: Cell biology; Osteoblasts; Nano-hydroxyapatite/polyamide 66/glass fiber