Zinc borate

Zinc borate is a bioactive inorganic compound with characteristics such as osteoinduction, promotion of angiogenesis, antioxidant properties, anti-mutagenicity, and cytotoxicity. In bone tissue engineering, it is often incorporated into chitosan scaffolds. By releasing zinc and boron ions, zinc borate induces human dental pulp stem cells to differentiate into osteoblasts, upregulates bone-related gene expression, and facilitates calcium deposition. It also enhances angiogenesis through the upregulation of key factors like vascular endothelial growth factor. Zinc borate exhibits antioxidant capacity by scavenging free radicals and specifically reduces mutagenicity under certain conditions. Although it decreases the survival rate of mouse fibroblasts, it remains useful for research in bone tissue engineering.

Zinc borate supports the survival of stem cells from human exfoliated deciduous teeth (SHEDs) when loaded onto chitosan scaffolds at a concentration of 1.0% (w/v) for 7-21 days, significantly increasing the absorbance values at 570 nm to approximately 0.29, 0.41, and 0.57, while also enhancing alkaline phosphatase (ALP) activity. In these scaffolds, zinc borate promotes the upregulation of osteogenesis-related genes (Runx2, OPN, and OCN) and angiogenesis-related genes (VEGF, Ang-1) during osteogenic differentiation in SHEDs. In a cell-free assay, zinc borate at 1 mg/mL for 30 minutes demonstrated low DPPH radical scavenging activity with an inhibition rate of 13.50% at the same concentration. Moreover, zinc borate (0.04-0.2 mg; 72 h) displayed a low antimutagenic effect against 4-NPD induced mutagenicity in Salmonella typhimurium TA98 strains, and it showed no antimutagenic activity against sodium azide-induced mutagenicity in TA100 strains. Additionally, zinc borate exhibited cytotoxicity towards mouse fibroblast cells L929, with IC50 values of 40.70 µg/mL at 24 hours and 32.93 µg/mL at 72 hours when concentrations ranged from 0.3 to 76.19 µg/mL.