Preparation and Characterization of Vancomycin-Loaded Microsphere Composite Scaffolds

Abstract

Objective: To fabricate and characterize sustained release antibacterial microsphere composite scaffolds for bone tissue engineering. Methods: First, poly(lactic acid glycolic acid) (PLGA) copolymer, chitosan (CS), and hyaluronic acid (HA) were used to prepare porous microspheres by the emulsion method. Vancomycin (VA) hydrochloride was loaded onto the microspheres (VA@PLGA-CS-HA) for sustained release of drug, after which hydroxyapatite (HAP) was added (VA@PLGA-CS-HA/HAP). The detailed in vitro characterization of the antibacterial sustained-release microspheres was performed using various techniques including the Cell Counting Kit-8 assay; hemolysis, osteogenic, and antibacterial experiments; scanning electron microscopy (SEM); and mechanical testing. Results: SEM showed that the sustained-release PLGA-CS-HA microspheres had a regular spherical shape, and the composite scaffolds of VA@PLGA-CS-HA/HAP microspheres were compact in structure. The relative colony-forming unit was less than 3% after 14 d of intervention. Cytotoxicity testing revealed that the relative growth rate of MC3T3-E1 and MG-63 osteoblast cells was more than 80% when the concentration of VA did not exceed 50 mg/mL. The mechanical strength of the scaffolds was comparable to that of human cancellous bone. The composite scaffolds enhanced the alkaline phosphatase activity of MG-63 cells and promoted the mRNA expression of osteogenic genes such as runt-related transcription factor 2, osteocalcin, osteopontin, and collagen. Conclusion: VA@PLGA-CS-HA microspheres can control the slow and sustained release of VA in vitro. The VA@PLGA-CS-HA/HAP microsphere composite scaffolds has a slower degradation rate and good antibacterial and mechanical properties in vitro.