A study on the preparation of a BGN-loaded thermosensitive adhesive and its performance in barrier membrane fixation

To investigate the barrier membrane fixation performance and enhanced guided bone regeneration (GBR) capability of a thermosensitive adhesive containing bioactive glass nanoparticles in order to provide a novel solution for membrane fixation during GBR procedures.

M2NP@BGN (methoxyethyl acrylate-co-N-isopropylacrylamide-co-protocatechuic acid@Bioactive glass nanoparticle), a thermosensitive adhesive, was synthesized via free radical polymerization by compositing methoxyethyl acrylate, N-isopropylacrylamide, and protocatechuic acid into a basic adhesive that was modified with bioactive glass nanoparticle (BGN). The successful fabrication of basic adhesive M2NP was characterized by attenuated total reflection-Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The thermosensitive adhesive M2NP@BGN (BGN concentration of 1 mg/mL) was characterized by scanning electron microscopy and a rheometer. By adjusting the BGN concentration (0.1 mg/mL, 0.5 mg/mL, 1 mg/mL, and 2 mg/mL), the adhesive and mechanical strengths were investigated with a universal testing machine. Biocompatibility was evaluated with a cell counting kit-8 assay and hemolysis test to identify the optimal formulation. The optimal material’s extract was co-cultured with mouse bone marrow mesenchymal stem cells, and its osteogenic activity was examined in vitro by quantitative real-time PCR, alkaline phosphatase, and alizarin red S staining. The rat mandibular defect model was established, filled with bone graft, and divided into 3 groups based on membrane fixation method: M2NP@BGN (BGN concentration of 1 mg/mL) fixation group (M2NP@BGN), titanium nail fixation group (Nail), and unfixed control group (Negative). Bone regeneration was analyzed after 8 weeks by micro computed tomography and histological staining.

M2NP@BGN (BGN concentration of 1 mg/mL) was successfully synthesized and demonstrated rapid gelation under warm, humid conditions. The adhesive with a BGN concentration of 1 mg/mL exhibited the highest adhesive strength (P < 0.001) and significantly enhanced mechanical strength (P < 0.001) under 37℃ wet conditions. All formulations showed excellent biocompatibility, with cell viability > 80% and hemolysis ratio < 5%. M2NP@BGN (BGN concentration of 1 mg/mL) significantly upregulated the expression of Runx2 and Col Ⅰ (P < 0.001) and enhanced the activity of osteogenic differentiation markers (P < 0.05). In the animal model, the M2NP@BGN group (BGN concentration of 1 mg/mL) achieved significantly higher bone volume fraction and better bone maturity compared to the negative and nail groups (P < 0.05).

M2NP@BGN (BGN concentration of 1 mg/mL) combines excellent wet adhesion with potent osteogenic activity, enhances the bone augmentation efficacy of membranes, and presents a novel fixation strategy with significant clinical translation potential for GBR therapy.