Preparation Of Mesoporous Silicon Microspheres And Study Of Cell Switches

In recent years.with the rapid development of nanotechnology,functional nanomaterials as a new type of drug carrier has attractive potential and broad application prospects in drug-targeted transport and medical care.Mesoporous silica has the advantages of ordered pore structure,large and continuously adjustable pore size,high specific surface area,good biocompatibility,and abundant surface silanol,which has many advantages in catalysis,adsorption,separation,medicine,biomedical applications.At the same time,great progress has been made in detecting biosensors of small molecules such as ATP by using aptamer as a sensitive unit,which has the characteristics of configuration diversity,good biocompatibility,and specific binding with target molecules.Therefore,MCM-41-type mesoporous silica is used as an artificial cell,fluorescent aptamer sensor is used as a channel switch of artificial cells,and the effect of both small molecule sensitivity and fluorescence is sealed while sealing the microsphere pores so as to establish a cyclic small molecule transport and signal transduction system with closed circulation.The main work of this thesis is as follows:(1)In this paper,the modified soft template method was used to prepare monodisperse mesoporous silica nanospheres with different morphologies under different conditions,mainly including the content of ethanol,the temperature of reaction system,the amount of silicon source(TEOS)and so on condition.Topography is divided into four categories are directly through the hole spherical,straight through the hole rod-shaped,through-hole channel bean-shaped and spherical radiation.The morphology and pore size distribution of mesoporous silica particles can be clearly seen by high-power transmission electron microscopy.The small-angle X-ray diffraction peaks show three diffraction peaks(100,110 and 200 peaks,where(100)is a strong peak)between 20=1-8°,which is a typical MCM-41 type mesoporous silica.Through the nitrogen adsorption-desorption test,the characteristics and trend of the curve conform to the Langmuir type IV nitrogen adsorption-desorption isotherm characteristic curves of the typical mesoporous materials,and the product has a high specific surface area(about 900 cm3/g)and uniform pore size(2.8 nm).Surface modification of microspheres through the Zeta potential changes and infrared spectroscopy analysis,the modification was successful.(2)One kind of ATP fluorescent aptamer probe was designed using carboxyfluorescein(FAM)as the energy donor and AuNPs as the energy receptor to attach the single-stranded DNA to the surface via the Au-S bond.Fluorescence resonance energy transfer system(FRET)was constructed by hybridizing DNA strands in different buffers to prepare amino-modified fluorescent ATP aptamer probes.(3)We explored that the ATP fluorescent aptamer probe was loaded on the surface of mesoporous silica microspheres to activate the carboxyl groups modified by mesoporous silica under the action of EDC or NHS,and reacted with amino-modified single-stranded DNA.Then,a fluorescent probe loaded with Si02 microspheres was obtained by hybridization between DNA strands in PBS buffer.The experimental results showed that when the concentration of TET-DNA-NH2 was lOOnM,the maximum loading capacity of mesoporous silica microspheres was 100 nmol/g,and the loading ratio was 58%.On this basis,hybridization with Au-DNA was carried out in PBS buffer,the fluorescence quenched,and the fluorescence recovered after the addition of ATP.Through TEM images,it is clear that gold nanoparticles adhere to the surface of the microspheres.