Design And Synthesis Of Monolithic Hierarchically Porous Silica For Enzymatic Bioreactor

Enzymes are efficient,specific and green biocatalysts which can be used in field of food production,pharmaceutical preparation,biosensor and medicine.For the application of enzymes in industry,problems such as separation and re-use of enzymes from solution and catalytic activity of enzymes out of natural environment should be solved.By immobilization of enzymes in materials,we can realize the large-scale use of enzymes.Nowadays,major problems in the field of enzymes immobilization focused on improving the catalytic activity and stability of enzymes and realizing device of bioreactor.Immobilization of enzymes based on the property of carrier materials.With the properties of high specific surface area,ordered mesoporous structure and uniform tunable pore size,mesoporous silica which can be synthesized in kinds of morphologic structures.The abundant Si-OH on surface of silica could be easily modified by different organic functional groups.With all these advantages,mesoporous silica could serve as the ideal support for enzymes.However,enzymes tend to leak from the silicate material for the weak adhesion.Gold nanoparticles which are biocompatible,can combine with enzymes by electrostatic interaction,and do not inactivate the biomacromolecule.Immobilization of enzymes in monolithic macro-mesoporous silica/gold nanoparticle could make it easier to improve the diffusing rate of substrate in the macropore,and mesopore provides abundant of binding sites of enzymes,gold nanoparticle can enhance the catalytic stability of enzymes.What's more,the monolithic bioreactor could be easily separated from the catalytic reaction system and is suitable for continuous catalytic reaction in industry.The research idea of the work includes two steps.Firstly,by changing the ratio of the reactants and hydrothermal time,the morphologic structures and diameter of mesopore could be regulated.Choosing the monolithic macro-mesoporous silica in which the diameter of mesopore is suitable for the molecular dimension of horseradish peroxidase(HRP).Then add gold nanoparticle in the monolith,and immobilize HRP by the monolithic macro-mesoporous silica/gold nanoparticle material and study the effect of gold nanoparticle to the enzyme.The main results are as followed:1.The morphologic structure and the diameter of mesopore could be easily regulated by changing the time of hydrothermal treatment of the monolithic material.2.Gold particle can improve the catalytic activity and stability of HRP.HRP immobilized in monolithic macro-mesoporous silica/gold nanoparticle shows higher catalytic activity and stability than HRP immobilized in pure silica,and the relative catalytic activity increases from 30% to 65% after 5 times of recycling run.