Transformable Carbonate Apatite Chains As a Novel Type of Bone Graft.

The aging global population is generating an ever-increasing demand for bone regeneration. Various materials, including blocks, granules, and sponges, are developed for bone regeneration. However, blocks require troublesome shaping and exhibit poor bone-defect conformities; granules migrate into the surrounding tissues during and after filling of the defect, causing handling difficulties and complications; and sponges contain polymers that are subject to religious restrictions, lack osteoconductivity, and may cause inflammation and allergies. Herein, carbonate apatite chains that overcome the limitations of conventional materials are presented. Although carbonate apatite granules migrate, causing inflammation and ectopic calcification, the chains remain in the defects without causing any complications. The chains conform to the defect shape and transform into 3D porous structures, resulting in faster bone regeneration than that observed using granules. Thus, these findings indicate that even traditional calcium phosphates materials can be converted to state-of-the-art materials via shape control. Carbonate apatite chains can be easily filled in the bone defect without migration. The chain's transformability improves the conformity to the bone defect and functions as a cell scaffold. These advantages enable faster bone regeneration with minimal concerns regarding complications, user-friendliness, and use restrictions. Thus, carbonate apatite chains overcome the limitations of conventional materials.image