A comprehensive study on bioactivity, mechanical and tribological behavior of copper-doped borosilicate glass derived from natural waste for dental applications

Abstract

The present study investigates in-vitro biomineralization, mechanical, and tribological properties of bioactive borosilicate glass composed of 31B2O3–20SiO2-(24.5-x)Na2O-24.5CaO and xCuO (mol%). Glass was manufactured using conventional melt-quench technique, utilizing chemicals partially derived from bio-waste, with varying copper oxide (CuO) content (x = 0, 1, 3, and 5). In-vitro study was conducted by immersing the specimens in simulated body fluid for 21 days. The formation of apatite layer was confirmed using FTIR, XRD and FESEM-EDS. Vicker's micro hardness tester and a universal testing machine measured hardness and compressive strength, while a pin-on-disc tribometer assessed wear. MTT assay was performed for all the specimens using osteosarcoma MG63 cell line. The study revealed that substituting copper in place of sodium increased the ion dissolution and improved the formation of the apatite layer hence, enhanced the bioactivity, however, accompanied by a gradual decrease in hardness and compressive strength. BSG-0 exhibited the highest hardness (6.64 GPa) and compressive strength (86.81 MPa), while wear resistance weakened with higher CuO content, notably in BSG-5 with the highest specific wear rate (0.072 mm³/N-m) under a 5 N load. Although MTT assay showed non-toxicity for all specimens, except BSG-5, the compounds demonstrated cell tolerance and growth stimulation. In conclusion, the study suggests that CuO-doped borosilicate glasses exhibit superior bioactivity, making them potentially effective for bone filling, wound healing, and dental applications, despite a compromise in mechanical strength and wear resistance.