Preparation Of Silicon Hybrid Microgel And Its Influence On Pre-osteoblasts

The traditional synthesis method of silicon dioxide（SiO₂）usually involves harsh synthesis conditions such as high temperature and pressure,strong acid and alkali.On the contrary,organisms such as diatoms and siliceous sponges in nature can generate complex and ordered hierarchical structure of SiO₂under mild physiological conditions.Amine-containing molecules with a similar structure to the organic matrix in these organisms are selected as templates,and SiO₂ and its composite nanomaterials can be synthesized in a normal temperature,normal pressure,and near-neutral aqueous solution.Unlike most work that uses vinyl microgels as templates,this paper uses the cationic amine-epoxy microgels（MG）previously developed by our group as templates for biomimetic silicification research.After confirming that the silicon hybrid microgel（sMG）was successfully prepared,it was deposited on the surface to study the mineralization ability of this surface in simulated body fluids（SBF）,and to explore the influence of the sMG modified surface on adhesion,proliferation and differentiation behaviors of MC3T3-E1 pre-osteoblasts.The MG obtained by amine-epoxy click addition is used as a template,and tetraethyl orthosilicate（TEOS）is used as a silicon source to prepare a silicon hybrid microgel under ambient conditions.The effect of the silicification time and the amount of TEOS on sMG was studied.The sMGs obtained under the experimental conditions are all positively charged and responsive to temperature.Extending the silicification time to 24 h,sMG with a SiO₂ content of more than 40%can be obtained.Besides,the sMGs became structurally more rigid to resist drying induced deformation and exhibited a rugged surface texture.In addition,by increasing the amount of TEOS,sMG with a larger particle size can be obtained.Mechanistically,the aminated nature of the MGs was proved beneficial for the success of their silicification,fulfilling dual functions of catalyst for TEOS hydrolysis and template for SiO₂ deposition.Similar to the previous research on MG,sMG can also be used as a reducing agent and stabilizer to react with chloroauric acid（HAu Cl₄）to form a gold-loaded silicon hybrid microgel.In addition,due to the hydrolysis of a large number of Si-R or Si-OH groups on the surface of SiO₂,sMG stored in water for 6 months will degrade.Through electrostatic adsorption,the sMGs provided a facile yet robust option for surface modifications toward bone related applications.The surface on which sMG was deposited was immersed in SBF,and induced mineralization of apatite was observed.In vitro MC3T3-E1 pre-osteoblast cell studies showed that cell adhesion,morphology,proliferation and differentiation behaviors could be influenced by both sMG types and their adsorption density.In particular,the cells exhibited elongated and greatly polarized morphology on the surface with a high adsorption density of sMGs of 43%SiO₂.It was postulated that the rugged appearance of such sMGs could have presented a hierarchically structured surface toward cells,which may be used for the engineering of cell-surface interactions.