Biomimetic mineralisation of eggshell membrane featuring natural nanofiber network structure for improving its osteogenic activity.

Designing reasonably priced bioactive organic-inorganic hybrid materials featuring osteogenic activity has received a significant interest in the bone tissue engineering field. In this study, eggshell membrane (ESM), which consists mostly of proteins exhibiting fibrous network structure, was utilised innovatively as a template to prepare eggshell membrane/hydroxyapatite (ESM-HA) composites using a versatile biomimetic mineralisation technique. In addition, the surface morphology and composition, hydrophilicity, crystallinity, and thermal stability of both sides of ESM and ESM-HA composites were systematically studied. Results indicated that both sides of ESM exhibited excellent biomimetic mineralisation ability, and the hydrophilicity and thermal stability of ESM were effectively improved by the introduction of HA. Moreover, in vitro experiments on MC3T3-E1 cells revealed that the inner side of the ESM was more beneficial to cell proliferation and adhesion than the outer side. Remarkably, the proliferation, adhesion and spreading, as well as the alkaline phosphatase (ALP) activity and expression of bone-related genes and proteins (runt-related transcription factor 2, ALP, collagen type I, and osteocalcin) on both sides of ESM-HA composites were significantly higher compared to those of the original ESM. These findings suggested that ESM-HA composites obtained using biomimetic mineralisation could be potential new materials for future bone tissue repair.