Lysostaphin is highly effective on eliminating methicillin resistant Staphylococcus aureus (MRSA). In order to achieve controlled release of lysostaphin, a biocompatible drug carrier is needed. Hydroxyapatite/chitosan (HA/CS) composites were chosen to carry lysostaphin and sample composites with different weight ratios of HA to CS, including 80/20, 70/30, 60/40, and 40/60, were prepared. Multiple analyses were performed to determine the structural and physicochemical properties of the composites, including scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. We immersed HA/CS composites loaded with 1 wt% lysostaphin to test in vitro release activity and cultured MC3T3-E1 cells to carry out biocompatibility test. The result of the release behavior of the composites revealed that the controlled release of lysostaphin from 60/40 HA/CS composites was the highest release rate of (87.4 ± 2.8)%, which lasted for 120 hours. In biocompatibility testing, MC3T3-E1 cells were able to proliferate on the surface of these composites, and the extract liquid from the composites could increase the growth of the cells. These results demonstrate the controlled release of lysostaphin from HA/CS composites and their biocompatibility, suggesting the potential application of these composites to bone injury and infection applications.

BACKGROUND: Hydroxyapatite/chitosan (HA/CS) complex may act as a drug carrier for drug release, but little is reported about the release amount and antibacterial effect of minocycline-HA/CS (Mino-HA/CS) complex. OBJECTIVE: To investigate the in vitro release and antibacterial property of Mino-HA/CS complex. METHODS: HA/CS and Mino-HA/CS were prepared using co-precipitation method. The surface and cross-section features of the complexes were observed under scanning electron microscopy. The porosities were measured according to Archimedes Principle. The release of minocycline hydrochloride was measured by high performance liquid chromatography with the simulated saliva as drug release media. In vitro antibacterial effect on Porphyromonas gingivalis and Staphylococcus aureus were measured by bacteria-inhibiting ring method. Biological toxicities were evaluated via cel counting kit-8cel proliferation assay. RESULTS AND CONCLUSION: The porosity of Mino-HA/CS was larger than that of HA/CS, with the average porosity of 53.99%. Single-day release amount of Mino-HA/CS could maintain at the level of 0.5-1 μg per day for a long-term. Bacteriostatic rings of Porphyromonas gingivalis and Staphylococcus aureus stil existed clearly after 7 days. Cel proliferation assays showed that Mino-HA/CS extract had the significant effect on promoting cel proliferation. These findings indicate that the Mino-HA/CS sustains the release of minocycline at a relatively stable level within a longer period, shows good inhibitory effect on Porphyromonas gingivalis and Staphylococcus aureus and promotes the proliferation of periodontal ligament cel s.