Figure 1.

A biomimetic biphasic scaffold to recapitulate endochondral ossification. A) Schematic of endochondral ossification at the growth plate of a long bone. Histological (H&E) staining of a mouse femur reveals ossification centers (yellow boxes) adjacent to the hypertrophic cartilaginous matrix. Ossification centers contain central blood vessels, osteoblast lining, and bone matrix. B) Schematic depicting the composition of the biphasic biomimetic scaffold. Phase 1 is composed of a chondroitin sulfate (CS) matrix decorated with whitlockite calcium phosphate nanoparticles (WHNPs). Phase 2 is composed of Matrigel, a basement membrane (BM) hydrogel. C) Schematic depicting cell seeding. The cells (MSCs + ECFCs) occupy the scaffold’s porous space and mediate the progressive formation of osteovascular niches and then ossification centers in vivo. D) Scaffold fabricated using a cylindrical mold (4 mm in diameter and 1 mm in height). Macroscopic photographs of the lyophilized (Phase 1) and reconstituted (Phase 1 + Phase 2) scaffold. E) Schematic depicting the fabrication process of a scaffold with a customized anatomical geometry.