Engineering bone formation with peptidomimetic hybrid biomaterials.

Bone exhibits hierarchical levels of organization from macroscopic to microscopic, and nano- length scales. Furthermore, multiple bioactive peptides, as part of the collagenous and non-collagenous water soluble glycoproteins and proteoglycans in the bone ECM, interact with progenitor BMS cells to initiate the cascade of chemotaxis, differentiation, and mineralization. In this work, a nanofiber hydrogel/apatite composite matrix is developed to mimic the laminated structure of the osteons in bone and to determine the effect of RGD and BMP peptides, grafted to the composite, on osteogenic differentiation and mineralization of BMS cells. For four-layer laminates, the Young's modulus of the laminated composites was four times that of the nanofibers alone. BMS cells seeded on RGD+BMP peptide modified composites showed synergistic 4.9- and 11.8-fold increase in calcium content from day 7 to 14 and 21. These findings are potentially useful in developing engineered scaffolds for bone regeneration.