Magnesium-based layered double hydroxides nanosheets: a new bone repair material with unprecedented osteogenic differentiation performance

Osteonecrosis of femoral head (ONFH) has been one of the most common diseases, and thus the development of novel biomaterials with superior osteogenic ability is the key issue. In this work, Yb-containing MgAl-layered double hydroxide (LDH) monolayer nanosheets (MgAlYb-LDHs) are designed and synthesized, which was used as a new biomaterial with outstanding osteogenic differentiation ability. The LDHs monolayer nanosheets give a high loading content (LC) of 197% for alendronate (AL) with an encapsulation efficiency (EE) of 98.6%. Notably, outstanding in vitro osteogenic differentiation performance of MgAlYb-LDHs was demonstrated in transcriptional level of Collagen I, with 3000.68-fold enhancement compared with the blank control. For in vivo tests with rabbits, the total volume of bone regeneration treated with LDHs group was 2.77 and 1.41 times larger than the negative control group and positive control group (autologous bone graft, clinical gold standard) at 8 weeks postoperatively. In addition, with the degradation of AL/LDHs, the bone mass density (BMD) of femoral head increased by 1.52 times compared with positive control group at 8 weeks postoperatively. Therefore, this work provides a new perspective for the design and preparation of 2D monolayer MgAlYb-LDHs and its drug formulation (AL/LDHs), which shows great promises in ONFH accompanied by osteoporosis.