# Natural Nacre-Derived Biomimetic Materials for In Vivo Bone Regeneration

## TL;DR

This study shows that combining nacre-derived materials with porous silicon enhances bone regeneration in rats, offering a promising new strategy for bone repair.

## Contribution

The novel contribution is demonstrating the synergistic effect of nacre and porous silicon in promoting in vivo bone regeneration.

## Key findings

- The nacre–pSi composite produced near-complete defect bridging and higher bone mineral density.
- Osteoid deposition occurred directly on material surfaces with no inflammation observed.
- Combining nacre with porous silicon significantly enhances bone regeneration compared to individual materials.

## Abstract

Bone regeneration in critical-size defects requires biomaterials that provide both structural support and appropriate osteoinductive cues. Natural nacre contains an organic matrix rich in acidic macromolecules with reported osteogenic activity; however, its in vivo regenerative potential remains insufficiently explored. This study evaluated the bone regenerative capacity of nacre-derived materials alone and combined with oxidized porous silicon microparticles (pSi-MP), a bioactive material known to release silicic acid and support mineralized tissue formation. Critical-size defects were created in four caudal vertebrae of Wistar rats and filled with nacre, pSi-MP, a nacre–pSi composite, or left empty. After 60 days, bone formation was assessed using micro-computed tomography and non-decalcified histology. Empty defects failed to regenerate, whereas nacre and pSi-MP individually promoted partial mineralized tissue deposition. The nacre–pSi composite produced the most extensive repair, showing near-complete defect bridging, higher bone mineral density, and seamless integration of particles within newly formed bone. No inflammation or adverse reactions were observed, and osteoid deposition occurred directly on material surfaces. These findings demonstrate that nacre-derived materials exert intrinsic osteogenic effects in vivo and that combining nacre with porous silicon yields a synergistic response that significantly enhances bone regeneration. The composite represents a promising candidate for future bone repair strategies.