Alginate-based composite scaffolds loaded with streptomycin sulfate for bone regeneration: In vitro studies

Abstract

In this work, nanoceramic powders were prepared by the wet-chemical precipitation method. Furthermore, composite scaffolds were fabricated by blending alginate and gelatin with nanoceramic powders as fillers through the freeze-drying method to obtain various compositions of scaffolds, free and loaded with streptomycin sulfate. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy-dispersive X-ray analyses (SEM-EDX), and mechanical properties of the designed scaffolds were all investigated. The in vitro drug release was assessed with phosphate-buffered saline (PBS) at 37 °C and pH 7.4 for 28 days. In addition, kinetic drug release was characterized through mathematical models. The composite scaffold images SEM revealed porous surface morphology with variable pore sizes (113–426, 40–287 μm). The mechanical strength increased from 0.88 MPa to 4.86 MPa with the addition of higher nanoceramic content and streptomycin sulfate, while the swelling (%) decreased from 792% to 512% for the scaffolds containing fillers. In vitro bioactivity against the tested scaffolds revealed a deposition of hydroxy appetite on the scaffold's surfaces which is ensured through FTIR and SEM-EDX. The composite scaffolds revealed excellent biocompatibility, up to 90%. Also, the proliferation capability for the selected scaffolds showed increased cell populations after 48 h compared to the control. Further, the presence of streptomycin sulfate in composite scaffolds demonstrated an effective role in resisting bacterial infections with inhibition zones in a range from 10 to 22 mm as compared with the polymeric scaffolds, which had no antibacterial activity. Sustained drug release profiles from scaffolds were recorded (up to 87.96%). Overall, the results confirmed that scaffolds with (60 w/w %) of bio-nanoceramic filler in the presence of drug are the most appropriate composite scaffolds. Therefore, these developed scaffolds are a promising candidate to be used in repairing bone.