Objective: To fabricate a hydrogel loaded with inositol hexaphosphate-zinc and preliminarily evaluate its performance in self-mineralization and osteoinduction, thereby providing a theoretical basis for the development of bone regeneration materials. Methods: The hydrogel framework (designated DF0) was formed by copolymerizing methacryloyloxyethyltrimethylammonium chloride and four-armed poly(ethylene glycol) acrylate, followed by sequentially loading inositol hexaphosphate anions via electrostatic interaction and zinc ions via chelation. The hydrogel loaded only with inositol hexaphosphate anions was named DF1, while the co-loaded hydrogel was named DF2. The self-mineralization efficacy of the DF0 , DF1 and DF2 hydrogels was characterized using scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and selected area electron diffraction (SAED). The biocompatibility was assessed via live/dead cell staining and a CCK-8 assay. The osteoinductive capacity of the DF0 , DF1 and DF2 hydrogels on MC3T3-E1 cells was assessed via alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining. In the aforementioned cell experiments, cells cultured in standard medium served as the control group Results: The DF0, DF1, and DF2 hydrogels were successfully synthesized. Notably, DF1 and DF2 exhibited distinct self-mineralization within 6 days. Results from TEM, EDS, and SAED confirmed that the mineralization products were amorphous calcium phosphate in group DF1, and amorphous calciumzinc phosphate in group DF2. Biocompatibility tests revealed that none of the hydrogels (DF0, DF1, and DF2) adversely affected cell viability or proliferation. In osteogenic induction experiments, both ALP and ARS staining were intensified in the DF1 and DF2 groups, with the most profound staining observed in the DF2 group. Conclusion The developed inositol hexaphosphate-zinc hydrogel (DF2) demonstrates the dual capacity to generate calcium-phosphate compounds through self-mineralization while exhibiting excellent osteoinductive properties. This biocompatible, dual-promoting osteogenic hydrogel presents a novel strategy for bone regeneration.

Objective: 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. Methods: 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. Results: 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). Conclusion 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.

Objective:To compare the efficacy between dual stability constructs and modified Scott techniques for treatment of symptomatic spondylolysis in active adolescents.Methods:A retrospective study was conducted to analyze the clinical date of 64 active adolescents who had been treated for symptomatic spondylolysis at Department of Orthopedic Surgery, The 900th Hospital of Joint Logistic Support Force from January 2017 to October 2021. There were 59 males and 5 females with an age of (24.9±5.2) years. Responsible vertebral bodies were L 3 in 2 cases, L 4 in 10 cases, L 5 in 47 cases, and L 4 to L 5 in 5 cases; spondylolisthesis was accompanied in 9 cases. Depending on the surgical methods, the patients were divided into a dual stability constructs (pedicle screws and laminar screws) group (observation group, 31 cases) and a modified Scott group (control group, 33 cases). The 2 groups were compared in terms of operative time, bleeding volume, postoperative drainage volume, isthmus healing rate, rate of internal fixation failure, visual analogue scale (VAS) for low back pain, Japanese Orthopaedic Association (JOA) score and the good and excellent rate by JOA at postoperative 1 month, 3 months, and the last follow-up, and the incidence of complications. Results:There was no statistically significant difference in the preoperative general data between the 2 groups, indicating comparability ( P>0.05). All patients were followed up. The operation time in the observation group [(94.7±14.9) min] was significantly longer than that in the control group [(84.4±16.4) min] ( P=0.011), but there was no significant difference in intraoperative bleeding volume or postoperative drainage volume ( P>0.05). The healing rate of bilateral isthmi in the observation group was 93.5% (29/31), significantly higher than that in the control group [60.6% (20/33)], and the rate of internal fixation failure in the observation group (0) was significantly lower than that in the control group (12.1%, 4/33) ( P<0.05). At postoperative 1 month, 3 months, and the last follow-up, the VAS scores were significantly lower than the preoperative value in all patients while the JOA scores significantly higher ( P<0.05). At the last follow-up, in the observation group the VAS score [0 (0, 1.0)] was significantly lower than that in the control group [1(0, 2)], and the JOA score [(27.1±1.2) points] and the excellent and good rate by JOA [93.5% (29/31)] were significantly higher than those in the control group [(25.7±2.1) points and 75.8% (25/33)] ( P<0.05). In the control group, follow-ups revealed internal fixation failure in 4 cases due to the cable cutting out of the spinous processes, yielding a failure rate of 12.1%, while no internal fixation failure was observed in the observation group. Conclusions:Both dual stability constructs and modified Scott techniques can relieve the clinical symptoms of spondylolysis in active adolescents to various extents. However, dual stability constructs with pedicle screws and laminar screws may lead to a higher isthmus healing rate and better curative effects.