Exploring the bioactivity and antibacterial properties of silver and cerium co-doped borosilicate bioactive glass†

Abstract

Bone defects resulting from trauma or diseases that lead to bone loss have created a growing need for innovative materials suitable for treating bone-related conditions. The purpose of this study is, therefore, to synthesize and analyse the synergistic effects of cerium (Ce) and cerium–silver (Ce–Ag) doping of borosilicate bioactive glass (BBG) on the bioactivity, antibacterial properties, and biocompatibility for potential applications in bone tissue engineering. This study utilized a sol–gel Stöber method to synthesize doped BBGs based on S49B4. Characterization techniques were utilized to evaluate the thermal stability, elemental composition, structural integrity, and morphological properties of the synthesized Ce and AgCe-BBGs. Cytotoxicity was evaluated using a GMSM-K gingival cell line, while antimicrobial tests were conducted using clinical isolates of Escherichia coli and Staphylococcus aureus. The characterization results confirmed the successful incorporation of Ce and Ag, resulting in elongated pineal to spherical nanosized BG particles (33–68 nm). Thermal analysis indicated that silver exhibited lower thermal stability compared to cerium. Bioactivity tests indicated that while silver has intrinsic bioactive qualities, elevated cerium levels above 0.5 wt% may inhibit or delay apatite formation by generating insoluble cerium phosphate ions. Lactate dehydrogenase assays demonstrated that among other BBGs, SBAgCe1 showed the highest LDH activity, suggesting mild cytotoxicity. The co-doped BBG exhibited strong antibacterial activity through a complex interaction between Ag and Ce ionic exchange. Nonetheless, a careful balance of Ce and Ag concentrations is critical, as high levels can compromise bioactivity and increase cytotoxicity. The results highlight the potential of SBAgCe0.5 as a candidate for bone tissue engineering applications due to its favourable bioactivity, and antibacterial and cytocompatible properties, emphasizing the importance of optimizing dopant concentrations for therapeutic applications in favour of good health and the well-being of humanity.