Brucine Sulfate, a Novel Bacteriostatic Agent in 3D Printed Bone Scaffold Systems

Bacterial infection is a common complication in bone defect surgery, in which infection by clinically resistant bacteria has been a challenge for the medical community. Given this emerging problem, the discovery of novel natural-type inhibitors of drug-resistant bacteria has become imperative. Brucine, present in the traditional Chinese herb Strychnine semen, is reported to exert analgesic and anti-inflammatory effects. Brucine's clinical application was limited because of its water solubility. We extracted high-purity BS by employing reflux extraction and crystallization, greatly improved its solubility, and evaluated its antimicrobial activity against E. coli and S. aureus. Importantly, we found that BS inhibited the drug-resistant strains significantly better than standard strains and achieved sterilization by disrupting the bacterial cell wall. Considering the safety concerns associated with the narrow therapeutic window of BS, a 3D BS-PLLA/PGA bone scaffold system was constructed with SLS technology and tested for its performance, bacteriostatic behaviors, and biocompatibility. The results have shown that the drug-loaded bone scaffolds had not only long-term, slow-controlled release with good cytocompatibility but also demonstrated significant antimicrobial activity in antimicrobial testing. The above results indicated that BS may be a potential drug candidate for the treatment of antibiotic-resistant bacterial infections and that scaffolds with enhanced antibacterial activity and mechanical properties may have potential applications in bone tissue engineering.