Effect of peptide secondary structure on calcium phosphate mineralization for bone regeneration

Biomineralization often inspires new approaches to the synthesis of bone repair materials. Calcium phosphate mineralization is regulated by peptides, the function of which is influenced by their secondary structure. However, the specific role of secondary structure in mineralization and the osteogenic properties of its products remain unclear. In this study, we use ion concentration to regulate the secondary structure of P11-4, a peptide with potential for clinical applications, to investigate the issue. We found that P11-4 with the helix structure changes the shape of calcium phosphate and enhances its osteogenic properties. With the increase of phosphate from 0.5 mM to 1.5 mM, the helix structure and part of the sheet structure of P11-4 transformed into a random coil structure. P11-4 induced the formation of brushite (DCPD) and the aggregation of calcium phosphate particles. P11-4 with the helix structure inhibited the formation of needle-like particles and enhanced the promotive role of calcium phosphate in osteogenic differentiation in vitro. Our findings may help to understand the role of peptides in biomineralization and design hard tissue repair materials.