[In vitro biological evaluation of PEGylated poly(glycerol sebacate)/β-TCP-coating modified magnesium alloy].

Purpose: To prepare PEGS/β-TCP modified magnesium alloy (PEGS/β-TCP/MZG) membranes by forming a glycolated poly(sebacate)/β-tricalcium phosphate (PEGS/β-TCP) coating on the surface of magnesium-zinc-gadolinium alloy (MZG) membranes, and to evaluate the osteogenic induction activity and immunomodulatory properties of PEGS/β-TCP/MZG using the material extract medium.

Methods: PEGS/β-TCP coating was prepared on the surface of MZG by solvent method, and the PEGS/β-TCP/MZG membrane was fabricated and compared with PEGS/β-TCP and MZG to examine the morphology, composition, and hydrophilicity. The amount of magnesium ions released and the pH value of the materials were tested after 3 days of immersion. The cell viability and osteogenic differentiation of MC3T3 cells induced by extract medium were investigated by CCK-8 assay, ALP and mineralized nodule staining. The cell viability and polarization of RAW cells induced by extract medium were then investigated. The expression of macrophage-secreted cytokines was examined by PCR analysis. GraphPad Prism 9.0 software package was used for statistical analysis.

Results: PEGS/β-TCP/MZG membranes with PEGS/β-TCP coating tightly embedded with MZG were successfully fabricated, and the material had good hydrophilicity. The results of degradation experiments indicated that the PEGS/β-TCP coating effectively slowed down the degradation rate of MZG, leading to a lower pH value and concentration of Mg ion in the extract medium of PEGS/β-TCP/MZG group. The results of in vitro cell experiments showed that PEGS/β-TCP/MZG had no significant effect on the proliferation activity of both MC3T3-E1 and macrophages. PEGS/β-TCP/MZG significantly enhanced the expression of ALP and mineralized nodule staining in MC3T3-E1. Although there was no significant difference in macrophage polarization pattern between PEGS/β-TCP and PEGS/β-TCP/MZG groups, PEGS/β-TCP/MZG further reduced inflammation based on the immunomodulation of PEGS/β-TCP coating related TNF-α expression and increased osteogenesis related TGF-β expression.

Conclusions: MZG membrane modified by PEGS/β-TCP may provide a new material option for the development of bone tissue engineering.