Monolithic DNApatite: An Elastic Apatite with Sub‐Nanometer Scale Organo–Inorganic Structures

Hydroxyapatite (HA) exhibits outstanding biocompatibility, bioactivity, osteoconductivity, and natural anti‐inflammatory properties. Pure HA, ion‐doped HA, and HA‐polymer composites are investigated, but critical limitations such as brittleness remain; numerous efforts are being made to address them. Herein, the novel self‐crystallization of a polymeric single‐stranded deoxyribonucleic acid (ssDNA) without additional phosphate ions for synthesizing deoxyribonucleic apatite (DNApatite) is presented. The synthesized DNApatite, DNA1Ca2.2(PO4)1.3OH2.1, has a repetitive dual phase of inorganic HA crystals and amorphous organic ssDNA at the sub‐nm scale, forming nanorods. Its mechanical properties, including toughness and elasticity, are significantly enhanced compared with those of HA nanorod, with a Young's modulus similar to that of natural bone. The novel realization of an elastic‐ceramic material, featuring ‘deoxyribonucleic apatite (DNApatite),’ is newly synthesized, incorporating both ceramic (hydroxyapatite, HA) and polymeric (single‐stranded DNA, ssDNA) elements at a sub‐nm scale to overcome the limits of conventional ceramic materials. This novel non‐composite material achieves synergistic effects from the combination of different material types, namely ceramic and polymer without additional phosphate ion.