Preparation And Properties Of Injectable Silk Fibroin-based Hydrogel Microspheres

The injectable nanofiber gel microsphere is a kind of microcarrier with broad prospect.Although natural silk nanofibers have excellent mechanical properties and biocompatibility,their gel microspheres still have some problems,such as complicated process,difficult shape control and environmental pollution.There is an urgent need to develop a green and mild technology to prepare uniform and environmentally friendly silk nanofiber wiki gel microspheres to meet the application requirements in materials science and engineering.Firstly,super long diameter silk nanofibers(SNFS)were prepared from domestic silk.Furthermore,sodium alginate(SA)was used as binder to improve the stability,hydrophilicity and bioactivity of SNF hydrogel microspheres.The SNF hydrogel microspheres were homogeneous with a diameter of 200μm～300μm,stable three-dimensional mesh structure and ultra-high specific surface area.By grafting specific peptides,SNF hydrogel microspheres were used to greatly improve the sensitivity of trypsin detection,with the detection limit as low as 9.75 p M.Secondly,human umbilical vein endothelial cells(HUVECs)were cultured on SNF gel spheres in vitro.The results showed that the SNF gel spheres supported the growth and proliferation of Huve Cs.Compared with the bulk SNF hydrogels,the gel microspheres had a larger specific surface area,which was more conducive to the transport of nutrients and metabolites,and provided more space for cell proliferation.Furthermore,SNF hydrogel/hydroxyapatite(HA)microspheres were constructed by organic/inorganic hybrid technology.Compared with traditional biomineralization,hybrid microspheres have the advantages of high efficiency,short flow and high and uniform HA content.At the same time,hybrid microspheres can significantly promote the growth of osteoblasts,suggesting that they may be used as cell culture vectors for injectable bone tissue engineering repair materials.Finally,doxorubicin(DOX)was loaded into SNF hydrogel microspheres to be used as drug controlled release vectors.The results showed that the microspheres could be sustainably released for more than 72 hours,and had a good sustained release effect.They also showed a similar inhibition effect on Hela cell growth by direct administration,and showed higher targeting.In conclusion,this study established an efficient and green method for the preparation of silk nanofibril injectable gel microspheres.The microspheres have excellent physical and chemical properties and biocompatibility,and show great application potential in biological detection,cell carrier,tissue engineering and other fields.