A Thermoresponsive injectable drug delivery system of chitosan/β-glycerophosphate with gellan gum/alginate microparticles

Synergistic Antioxidant and Anti-Ferroptosis Therapy via BPNS-Encapsulated Thermoresponsive Chitosan Hydrogel for Spinal Cord Injury Regeneration

Background: Spinal cord injury (SCI) is a devastating neurological condition with limited therapeutic options. Current clinical interventions predominantly rely on prolonged or high-dose pharmacological regimens, often causing systemic toxicity and adverse events. Although black phosphorus nanosheets (BPNSs) exhibit remarkable reactive oxygen species (ROS)-scavenging capacity to mitigate oxidative damage, their rapid degradation severely compromises their therapeutic efficacy. Methods: This study presents a thermosensitive hydrogel with rapid gelation properties by incorporating different proportions and concentrations of sodium alginate (SA) into a chitosan/β-glycerophosphate (CS/β-GP) hydrogel and loading it with BPNS for the treatment of SCI in rats. In vitro, the physical properties of the composite were characterized and the cytotoxicity and ROS scavenging abilities were assessed using PC12 cells; in vivo, behavioral tests, histopathological analysis, transcriptomics, immunohistochemistry, and Western blotting were performed to explore the therapeutic effects and mechanisms. Results: The results demonstrate that this hydrogel effectively slows BPNS degradation, exhibits a high ROS scavenging capacity, reduces lipid peroxidation, and thereby inhibits ferroptosis and apoptosis, offering neuroprotective effects and promoting motor function recovery. Conclusions: Our findings establish the CS/β-GP/SA-BPNS hydrogel as a multifunctional therapeutic platform for SCI, synergizing sustained drug release with ROS-ferroptosis-apoptosis axis modulation to achieve neuroprotection and functional restoration. This strategy provides a translatable paradigm for combining nanotechnology and biomaterial engineering in neural repair.

Vancomycin-Loaded Sol-Gel System for In Situ Coating of Artificial Bone to Prevent Surgical Site Infections

Surgical site infections (SSIs) related to implants have always been a major challenge for clinical doctors and patients. Clinically, doctors may directly apply antibiotics into the wound to prevent SSIs. However, this strategy is strongly associated with experience of doctors on the amount and the location of antibiotics. Herein, an in situ constructable sol-gel system is developed containing antibiotics during surgical process and validated the efficacy against SSIs in beagles. The system involves chitosan (CS), β-glycerophosphate (β-GP) and vancomycin (VAN), which can be adsorbed onto porous hydroxyapatite (HA) and form VAN-CS/β-GP@HA hydrogel in a short time. The VAN concentration from VAN-CS/β-GP@HA hydrogel is higher than minimum inhibitory concentration (MIC) against Staphylococcus aureus (S. aureus) at the 21st day in vitro. In an in vivo canine model for the prevention of SSIs in the femoral condyle, VAN-CS/β-GP@HA exhibits excellent biocompatibility, antimicrobial properties, and promotion of bone healing. In all, the CS/β-GP instant sol-gel system is able to in situ encapsulate antibiotics and adhere on artificial bone implants during the surgery, effectively preventing SSIs related to implants.