Antibacterial and osteogenic properties of vancomycin/PLGA-coated porous magnesium alloy scaffolds / 中华创伤骨科杂志

ABSTRACT

Objective:To evaluate the physicochemical properties, degradation and drug release behaviour, cytocompatibility and bacteriostatic properties in vitro of porous magnesium alloy scaffolds containing vancomycin/poly(lactic-co-glycolic acid) (PLGA). Methods:Porous magnesium scaffolds (Mg-2Zn-0.3Ca) were prepared using the template replication technique. The MgF 2 surface layer was obtained by high temperature fluorination. The vancomycin/PLGA porous magnesium alloy drug-loaded scaffolds were obtained by homogeneous lifting after submersion in a dichloromethane solution of PLGA containing vancomycin hydrochloride. According to the products at each stage of the preparation (scaffolds of magnesium alloy, magnesium fluoride alloy, PLGA coated magnesium fluoride alloy, and vancomycin/PLGA magnesium fluoride alloy), they were divided into an Mg group, an MgF 2 group, a PLGA group, and a vancomycin/PLGA group. Immediately after preparation, the material science characterization, degradation rate, drug release rate, antibacterial properties, hemocompatibility, and cell proliferation and differentiation ability of the scaffolds were measured and evaluated. Results:Vancomycin-loaded magnesium alloy scaffolds were successfully prepared with an average porosity of 66.39%. Their degradation rate [(0.540±0.102) mm/year] was significantly lower than that of the Mg ones [(10.048±0.297) mm/year] ( P<0.05). Their pH of degradation in Hank equilibrium salt solution was close to the physiological pH. Their release of vancomycin was fast in the first 48 h and gradually slowed down after 48 h. Their cumulative drug concentration reached a maximum of 43 mg/L at d 11; their vancomycin was still released slowly after d 11. The antimicrobial rate in the vancomycin/PLGA group (97.89%±0.28%) was significantly higher than that in the Mg group (74.92%±2.20%), the MgF 2 group (78.46%±2.59%) and the PLGA group (61.08%±4.21%) ( P<0.05). Their hemolysis rate (0.55%) was much lower than the requirement of ISO 10993-4 (5%). The extract liquid from them promoted the proliferation of rat bone marrow mesenchymal stem cells (BMSCs), showing a gradually increased proliferation rate from d1 (104.80%±5.13%) to d3 (112.36%±2.07%) and d7 (127.79%±4.61%). The calcium nodules in BMSCs were significantly increased at d 14, with an OD value of absorbance of 1.189±0.020, significantly higher than that in the Mg group (0.803±0.020), the MgF 2 group (0.878±0.028) and the PLGA group (0.887±0.026) ( P<0.05). Conclusion:Vancomycin/PLGA-loaded porous magnesium alloy scaffolds exhibit good material properties, antibacterial properties, biocompatibility and osteogenic properties in vitro.