The Synthesis And Mechanism Research Of Mesoporous Carbon Nanospheres As Drug Carrier

Mesoporous carbons are attracting increasing interest,since it possesses high surface area,large volume,thermodynamic stability and chemical inertness.For these,mesoporous carbon has been used to improve the bioavailability of poorly water-soluble and protect the protein drug from being digested by enzymes in the gastrointestinal tract.However,the mesoporous structure and morphology of mesoporous carbon are not enriched.And the synthesis method of mesoporous carbon lacks innovation.The main reason is that it is difficult to understand the forming mechanism of mesopores.Therefore,it still remains a big challenge in controlling the synthesis of mesoporous carbon with adjustable morphology,particle size and surface roughness,which would further impede the development of mesoporous carbon in various application.Therefore,there is an urgent need to synthesize mesoporous carbon with adjustable physicochemical properties,and make a study of its synthesis mechanism,which will increase the application of mesoporous carbon in pharmaceutical field.In this paper,we have synthesized a series of mesoporous carbon with adjustable morphology,particle size,mesopores size and surface properties,and explored application of the obtained materials as drug carrier.This thesis mainly focuses on two aspects:(1)Synthesis of dual-mesoporous carbon nanospheres(DMCNs)with predictable diameter by an acid-programmed controlled method.Both small diameter and bimodal mesopores are integrated in one single unit to synthesize DMCN.The diameter can be easily manipulated by adjusting the HCl concentration.Meanwhile,a linear function model is established to quantitatively control and predict the particle size.The main innovations are as follows:(?)An extended I~+X~-S~+mechanism is proposed to interpret the formation process of DMCNs.The surface incompatibility issues betweensilicananoparticle(SN,theinorganics)and resorcinol/formaldehyde(RF,the organisms)are addressed through the employment of inorganic/ionic/organic interaction.(?)The highly acidic driven method has effectively balanced the organic-organic,organic-inorganic and inorganic-inorganic assembly to control the polymerization kinetics,thus forming dispersed nanospheres.(?)Since the DMCN integrates both the advantages of small diameter(nanosize effect)and bimodal mesopore system(reduction of transport limitation)in one single unit,it exhibits an excellent release performance of poorly water-soluble drug.(2)Synthesis of N-doped and large mesoporous carbon spheres with adjustable litchi-like surface and particle size.The low IRT(Initial reaction temperature)can adjust the micelles with large size and less tight aggregation,resulting in the large mesopores.Moreover,particle size becomes uniform.At higher IRT,the micelle size can be smaller,resulting in the smaller mesopores.Meanwhile the particle size becomes larger.This result conflicts with heterogeneous nucleation and growth theory,which clarifies that higher temperature would facilitate nucleation and form more nuclei,consequently resulting in a smaller particle size.Therefore,the current understanding of nucleation and growth mechanism of nanospheres has been further extended.The main innovations are as follows:(?)When the IRT is increased to 40°C,hollow N-doped mesoporous carbon spheres are obtained.(?)By varying the solution polarity,the roughly litchi-like surface of NMCNs are obtained,which could significantly improve the cell uptake performance of NMCNs.(?)Insulin is loaded into NMCNs and used as oral preparation,and the results of animal experiment show an excellent performance in vivo hypoglycemic activity.