ABSTRACT
BACKGROUND: Bioglass has high brittleness and poor mechanical strength, which limits its application in bone defect of bearing part. Nitrogen oxide glass has higher strength and hardness. Therefore, nitriding treatment is expected to improve the mechanical strength of bioglass. OBJECTIVE: To analyze the effects of nitridation on the porosity, compressive strength, bending strength, degradation performance and mineralization activity of porous bioglass scaffolds. METHODS: This experiment was based on silicate glass (SiO2-CaO-P2O5-Na2O-ZnO), and nitriding it (SiO2 was replaced by 0%, 2%, 4%, 6% Si3N4, respectively). The basic glass (SiO2-CaO-P2O5-Na2O-ZnO-Si3N4) was prepared by melting method. The polyurethane foam was used as template and organic foam impregnation method was used to prepare porous bioglass scaffolds. The porosity, compressive strength, bending strength, and degradation performance in vitro of the porous bioglass scaffolds were measured in four groups. Four groups of scaffolds were immersed in simulated body fluid for 7 days. The surface morphology of the scaffold was observed with the scanning electron microscope. RESULTS AND CONCLUSION: (1) The porosity of the four groups had no statistical difference (P > 0.05). (2) With increased Si3N4 content, compressive strength and bending strength of porus bioglass scaffold increased, and there was statistical difference between each group (P < 0.05). (3) With increased Si3N4 content, the degradation performance of porous bioglass scaffolds decreased gradually in vitro. (4) Scanning electron microscope revealed that typical hydroxyapatite membrane was formed on the surface of porous bioglass scaffold without nitriding treatment and porous bioglass scaffold containing 2% Si3N4, but no hydroxyapatite membrane was formed in the other two groups. (5) Nitriding treatment can significantly enhance the mechanical strength of bioglass, but can reduce its degradation performance and mineralization activity in vitro.