Structure–Property Relationships in Streptomycin Sulfate–Incorporated Bioactive Glass/Chitosan Composite Scaffold: Physicochemical and Antibacterial Insights

In this study, a streptomycin sulfate-loaded bioactive glass/chitosan (STRS–BG/CH) composite scaffold was fabricated via an improved unidirectional freeze-drying method, with drug loadings of 20–40%. The scaffolds were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray analysis before and after in vitro testing. Antibacterial efficacy was evaluated against Gram-positive (Enterococcus faecalis, Staphylococcus aureus) and Gram-negative (Klebsiella pneumoniae, Escherichia coli) microorganisms via the agar diffusion method. The STRS–BG/CH scaffolds exhibited highly interconnected porous structures, prolonged antibacterial activity, and enhanced apatite-forming ability in vitro. Compared with bead-based carriers, scaffold-based systems provide enhanced structural integrity and interconnected porosity, which are advantageous for sustained drug release, apatite formation, and tissue integration. Accordingly, these multifunctional scaffolds may simultaneously provide localized antibacterial activity and potential relevance to bone tissue engineering applications. The prepared STRS–BG/CH scaffolds functioned as controlled release carriers for streptomycin sulfate while simultaneously maintaining antibacterial efficacy and bioactive performance. These results illustrate the importance of STRS–BG/CH scaffolds as a promising antibacterial bioactive scaffold system, warranting further biological investigation.