Novel green synthesized strontium doped electro-spun chitosan and alginate nanofibers in alveolar bone regeneration

Introduction: Alveolar bone regeneration requires bioactive scaffolds that mimic the extracellular matrix (ECM) while providing therapeutic cues to promote healing and resist infection. We aimed to green-synthesize strontium nanoparticles (SrNps) using the horsetail plant ( Equisetum ) and incorporate the SrNps into alginate and chitosan nanofibers to characterize and evaluate the antimicrobial and cytotoxic activity of strontium (Sr)-incorporated alginate and chitosan nanofibers. Materials and Methods: SrNps were synthesized using Equisetum extract and electrospun with alginate/chitosan to fabricate the nanofibers. Alginate, chitosan, Sr-alginate, and Sr-chitosan nanofibers were tested for antimicrobial activity against common oral pathogens, Candida albicans , Streptococcus mutans , and Lactobacillus, using zone of inhibition and time-kill kinetic assays. Further, cytotoxicity was assessed using the brine shrimp lethality assay. High resolution Scanning electron microscopy analysis of the nanofibers was performed to characterize the nanofibers. FTIR spectroscopy was used to confirm the incorporation of SrNps into the polymer matrices. Results: FTIR confirmed successful incorporation of SrNps into alginate and chitosan polymers. HR SEM analysis characterized the Sr-incorporated nanofibers. Sr-chitosan exhibited significant antimicrobial activity, with ZOI against Lactobacillus ranging from 11.97 ± 0.17, 14.25 ± 0.29, and 18.00 ± 0.35 mm at 25, 50, and 100 μg/mL, respectively, and ZOI against S. mutans was observed to be 11.93 ± 0.02 and 18.85 ± 0.56 mm at 50 and 100 μg/mL, respectively. All test formulations exhibited no significant cytotoxicity up to a 50 µg/mL concentration for 48 h. Conclusion: Sr-incorporated alginate and chitosan nanofibers are biocompatible materials, with Sr-chitosan nanofibers exhibiting significant antimicrobial activity. Further cell-line and in vivo studies need to be carried out to underscore their potential as promising tissue regeneration scaffolds.