Mineral encapsulation of microorganisms in calcified oral biofilms: implications for immune dysregulation and...

Oral biofilms represent highly organized microbial ecosystems embedded within extracellular matrices enriched with calcium and phosphate ions that promote the nucleation of calcium phosphate minerals, including hydroxyapatite. During plaque mineralization, microorganisms may become incorporated within calcium phosphate-protein matrices, forming mineralized microenvironments that facilitate microbial persistence while partially shielding pathogens from host immune surveillance. Hydroxyapatite crystals can also directly influence innate immune responses. Macrophages exposed to these particles exhibit altered polarization, impaired antigen presentation, and sustained low-grade inflammatory signaling accompanied by dysregulated tissue repair mechanisms. In biological fluids, calcium phosphate nanoparticles rapidly acquire a protein corona that modulates cellular uptake, biodistribution, and systemic interactions. These particles may disrupt intracellular calcium homeostasis, promote endothelial dysfunction, influence coagulation pathways, and contribute to vascular remodeling. We propose that calcium phosphate mineralization within oral biofilms encapsulates microbial cells within mineral-protein matrices that behave as protected reservoirs capable of systemic dissemination, immune modulation, and promotion of vascular calcification. This mineral encapsulation model provides a mechanistic framework linking opportunistic oral microorganisms with chronic inflammation and cardiovascular disease and suggests potential targets for therapeutic intervention.