In recent years, the composite hydrogels composed of micro-nano bioactive glass (MNBG) and gelatin are widely used in tissue regeneration. However, the relationship between hydrogels and MNBG in terms of mineralization and degradation is still unclear. In this paper, gelatin based composite hydrogels with different concentrations of MNBG were prepared, and the effect of MNBG on the mineralization and degradation properties of composite hydrogel was investigated by in vitro experiments. The results show that the composite hydrogel does not affect the bioactive ion release of MNBG, and the formation of negative curvature interface by a high concentration of MNBG aggregates is a necessary condition for composite hydrogels to mineralize. In addition, increasing the concentration of MNBG and quickly mineralizing to form hydroxyapatite layer can effectively reduce the degradation rate of gelatin based composite hydrogel.

Micro-nano bioactive glass (MNBG) has a good biological activity and is widely used in tissue engineering. In recent years, a variety of metal ions are incorporated into the network structure of materials during the preparation of MNBG, thereby endowing MNBG with various physicochemical and biological functional properties. However, the exact mechanism of interaction between the ion release products of MNBG and human cells is not fully clarified. This review represented the preparation methods and processes of MNBG and the application of its lysates in bone and tooth and other hard tissue repair, skin tissue repair, cancer treatment and cell imaging. This review could provide a reference for the further development of MNBGs applied to the biomedical field.

The structural origins of bone toughness at the nanoscale are not completely understood. Therefore, we performed in situ scanning using atomic force microscopy during macroscopic mechanical testing of antler and bovine bone, to reveal the origins of the irreversible plastic deformation at the mineralized collagen fibril (MCF) array and MCF levels. We found that the plastic deformation behavior at the nanoscale level could be divided into two stages. The first stage of plastic deformation at the nanoscale level was characterized by slippage between the MCF arrays, which contained mineral aggregate grains with regular shapes under load. In the second stage of nanoscale plastic deformation, the MCFs broke through the bonds of the extrafibrillar mineral aggregate grains and exhibited interfibrillar slippage. These nanoscale plastic deformation behaviors may thus be the origins of stress whitening and irreversible plastic deformation. Thus, the findings in this study not only shed light on the plastic deformation mechanisms of MCF arrays and MCFs, but also provide structural and mechanistic insights into bioinspired materials design and mechanisms of relevant bone diseases.