Bioactive functional sericin/polyvinyl alcohol hydrogel : biomaterials for supporting orthopedic surgery in osteomyelitis

Chronic osteomyelitis can be treated using non-biodegradable carriers for local antibiotic delivery, but a second surgery for their removal, which delays bone healing. A drug carrier with efficient antibiotic delivery, biodegradability, and supporting bone cell proliferation would be preferable. This study was aimed to develop ciprofloxacin-loaded sericin/polyvinyl alcohol (PVA) hydrogels as a dual-functional biodegradable carrier for infection treatment and bone regeneration. Sericin and PVA were mixed with different ratios (75:25, 50:50, and 25:75) and incorporated with 5 mg of ciprofloxacin. The hydrogels were prepared by a freeze-thaw method without using chemical agents. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were performed to characterize the hydrogels. The physical properties and biological activities of the hydrogels were evaluated. The results demonstrated that 75:25 and 50:50 formulations had a suitable pore size with a consistently porous structure. FT-IR characterization indicated the molecular motion of sericin and PVA molecules into the hydrogel. Based on the physical properties, 75:25 formulation demonstrated the greatest swelling ratio and degradation rate. Moreover, 75:25 formulation released high concentrations of ciprofloxacin, followed by a sustainable release of up to 88% within 35 days. The bacterial growth assay against Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli confirmed the antibacterial activity of the hydrogels. Furthermore, 75:25 and 50:50 formulations significantly induced the proliferation of osteoblast cells after incubation for 21 days. Therefore, ciprofloxacin-loaded sericin/PVA hydrogel, especially 75:25 formulation, could be considered as a promising option for chronic osteomyelitis treatment.