Gallium-integrated HA/CaCO₃ scaffold and its effect on gram-positive bacteria and osteoclastogenesis

The development of biomaterials capable of promoting bone tissue regeneration while simultaneously exhibiting antimicrobial activity is a highly relevant and timely topic, both in healthcare and economic terms. The present study aimed to produce scaffolds based on a composite of hydroxyapatite (HA) and calcium carbonate (CaCO₃) loaded with 2.5 and 5 wt% of gallium, known for its antimicrobial activity and only recently investigated for its potential to modulate bone metabolism. The characterization of the scaffolds, performed by X-ray powder diffraction, field emission scanning electron microscopy, and attenuated total reflectance Fourier transform infrared spectroscopy, shows a homogeneous distribution of gallium at the nanoscale and presence of tetracalcium diphosphate oxide beside HA and CaO. In vitro bioactivity test proved the growth of the new HA on the scaffolds after three days. Scaffolds were tested for their antibacterial activity against the gram-positive Staphylococcus aureus and Staphylococcus epidermidis, as well as for their ability to inhibit osteoclastogenesis. The results showed that released gallium interferes with the differentiation of precursor cells into mature bone-resorbing osteoclasts and showed moderate antibacterial effects against the tested strains.