Surface Modification And Biomimetic Mineralization Of Cellulose/Sodium Alginate Composite Aerogels

In this study,cellulose/sodium alginate(SA)composite aerogels were prepared via freeze-drying technique as a valid method for preparing three-dimensional(3D)scaffolds in tissue engineering.The ice crystal in the frozen hydrogel was sublimated by freeze-drying process,and the gap structure of air medium was obtained.Then the phosphorylated composite aerogel and carboxylated composite aerogel were modified by esterification and chemical oxidation,respectively.The biomineralization of cellulose/SA composite aerogels were investigated by means of artificial simulation mineralization.The biocompatibility of the mineralized cellulose/SA composite aerogels were investigated as well.The unmodified cellulose/SA composite aerogels were used as control.Study of phosphorylated composite aerogels revealed that the phosphate group was grafted onto the surface of the composite aerogels by esterification reaction.Compared with unmodified composite aerogels,the mineralization ability of phosphorylated composite aerogel materials was improved.The results showed that the deposition of apatite nanoparticles on the surface of phosphorylated composite aerogels was faster.Furthermore,the spherical apatite nanoparticles were aggregated as rod-like apatite crystals.The Ca/P molar ratio of HA on the surface of phosphorylated cellulose/SA composite aerogels is 1.45.CCK8 experiment and L929 cells culture showed that the cells were well grown on the mineralized phosphorylation composite aerogel extract.Conclusively,the phosphorylated cellulose/SA composite has the potential as a bone repair material.The dicarboxylic cellulose/SA composite aerogels were carried out with sodium peroxidate and sodium chlorite.The hydroxyl groups at C2 and C3 of cellulose and SA were oxidized into carboxyl groups,improving mineralization ability.Results showed that the formation of HA on the surface of dicarboxylic cellulose/SA composite aerogels was faster with smaller grain size,and the deposition layer was more uniform after mineralization for 7 d.It is noticeable that the dicarboxylic cellulose/SA composite aerogels show a Ca/P molar ratio with 1.35,promising a candidate for orthopedic biomaterial application.In addition,the L929 cells activity of cellulose/SA and dicarboxylic cellulose/SA composite aerogels extracts were both more than 80%.Conclusively,the dicarboxylic cellulose/alginate composite has the potential as a bone repair material.