Preparation And Properties Of Silicon-based Nano Bioactive Glass/sodium Alginate Composite Hydrogel

Bioactive glass（BG）is a kind of biomaterials that can generate solid bond with bone tissue,and promote replacement,repair and regeneration of bone tissue.In physiological conditions,BG is osteoconductive,osteoinductive and motivate angiogenesis,which significantly facilitates its application in bone repair and regeneration.However,the massive and powdery BG synthesized by the traditional melting method and sol-gel method are not only difficult to be shaped and fixed,but also make the local p H value of the bone defect too high when they are used alone.In this paper,nano bioactive glass（NBG）with high bioactivity was prepared.In addition,NBG was compound with sodium alginate（SA）which had good biocompatibility and nano-hydroxyapatite（n-HA）was added as another calcium source to prepare the ionic cross-linking NBG/n-HA/SA hydrogel scaffold.The main contents and results are as follows:（1）NBG with mesoporous structure was fabricated by template combined with sol-gel method using CTAB and P123 as composite templates.It was found that the dosage of CTAB could adjust the particle size of spherical NBG from 30 nm to 70 nm.When the addition of CTAB was 0.01 g,the particle size distribution of NBG was uniform and the sample had high specific surface area.Moreover,the HA was generated quickly after the NBG immersed in vitro,which inferred that the NBG had high bioactivity.（2）In the presence of D-gluconic acidδ-lactone（GDL）solution,NBG and n-HA which acted as calcium sources,could slowly release Ca²⁺and cross-link in situ with SA to obtain complex hydrogel.The results showed that the mixture of the precursor forming the network had good injectability and plasticity.Increasing the amount of GDL shortened the gelation time,but excessive GDL could affect the gelation,which was not conducive to the integrity of the network,and reduced the mechanical properties of the composite hydrogel.When the dosage of GDL was 0.75 g,the gel time of composite hydrogel could be regulated within 4-8 min,and the hydrogel had high compressive strength（170-220k Pa）.The ratio of calcium source to SA in the system had an important influence on the integrity of the cross-linking network.When the contents of other components were the same,calcium source concentration either too high or too low was not conducive to the formation of the porous network.When the mass ratio of calcium source to SA was 1:1,the cross-linking network was rather uniform,and the proportion of large pores around40μm was high.Immersion experiment in vitro showed that the composite hydrogel could promote the deposition of bone-like HA on the surface of the material.The cell experiments in vitro verified that the NBG/n-HA/SA composite hydrogel had no cytotoxicity and good cytocompatibility.The composite hydrogel could improve the activity of ALP of mouse bone marrow mesenchymal stem cells and had good osteogenic activity.（3）NBG/n-HA/SA/PNMA double network hydrogel with good toughness was obtained by adding PNMA radical polymerization network into NBG/n-HA/SA ionic cross-linking network.The addition of the second network compacted the structure of the porous network and improved the ability of the system to resist deformation.The fracture energy W of the double network hydrogel was up to 1.193 MJ/m³.The rheological tests showed that the storage modulus G’of the dual-network was about 10 times higher than that of SA single network at low strain.Under dynamic stress,composite hydrogels had higher shear resistance.The ion release tests in vitro showed that the dual-network hydrogel consumed PO₄^3-and Ca²⁺associated with the formation of HA.There are 37 figures,9 tables and 122 references.