Construction And Application Of Porous Silicon Particle Based On Gold Nanoparticles Modification

There are a lot of naturally occurring multi-functional porous structures in nature.Some porous structures play an important role in maintaining stable and rapid biochemical processes in living organisms.Before human have mastered the technology for producing porous structures,they often use the porous materials available in nature to meet the needs of production and life.For example,activated carbon,sponge has a shell of diatoms,etc.As mankind enters the information age,mankind's processing of microelectronic devices has entered the nanoscale.In the process,a method of fabricating microstructures using photolithography has been developed.Take advantage of this now mature technology combined with elaborate design of electrochemical corrosion,we obtain a discoidal porous silicon(DPS)nanomaterial with regular shape.It has uniform morphology,controllable pores,good biocompatibility and high specific surface area.Therefore,the adsorption capacity and loading capacity of this porous material for molecules or particles are very significant.This thesis is to take advantage of this material and use multidisciplinary interdisciplinaries such as biochemistry,nanotechnology,interface chemistry,etc.Gold nanoparticles(AuNP)were loaded into discoidal porous silicon(DPS),and the optimal conditions for in-situ reduction of gold nanoparticles on the surface and in the channels were discussed.A new form of three-dimensional hotspot matrix is obtained.Based on the characteristics of the material,experiments are designed to verify its performance in cancer treatment,detection,and simulation of enzymes,and to discuss it scientifically.It has good biocompatibility and practical application value,and further explores useful applications of functional nanomaterials.The main content of this thesis is as follows:(1)The silicon wafer is widely used as the basic material of the porous structure carrier on the earth,and the silicon wafer is processed using photolithography and electrochemical etching technology.Lithography can control the regular morphology of DPS,and electrochemical corrosion can control the inner diameter of holes on DPS.Finally,the prepared DPS is separated from the silicon wafer by ultrasonic method and collected.It was characterized by SEM,BET,and extinction spectrum.Make sure that the disc-shaped porous silicon material meets the expected characteristics.It was found in experiments that the size of the pores formed on the DPS is positively related to the current intensity during electrochemical corrosion.Therefore,the additional rate of DPS can be adjusted in this way to meet its specific needs as a carrier.Can control the formation of nanopores ranging from several nanometers to hundreds of nanometers.It is determined by the nature of the silicon material,which itself has a certain reducing property,and in a proper manner,the surface of the DPS can be modified by the nanoparticles already having functional molecules.This provides a means to later demonstrate the versatility of the composite material.(2)Utilizing its pore structure has been itself reducing.The DPS solid-liquid interface can send an in-situ reduction reaction to deposit and anchor gold nanoparticles within its surface and channels.Regulate the molar ratio between DPS and tetrachloroauric acid,control the relative strength of the nucleation reaction and growth reaction of nanoparticles,and under appropriate conditions can form a uniform particle size and densely arranged.Such densely arranged gold nanoparticles will strongly affect the characteristics of their plasmon resonance.By comparing the absorption spectra of composite particles with monodispersed AuNPs of the same particle size,it can be seen that the absorption peaks have a distinct red shift,which can move from 525 nm to about 800 nm.In this way we obtain a three-dimensional hotspot that converts light energy into thermal energy.The effects of reactant concentration,surfactant,temperature and reaction time on the deposition behavior of gold nanoparticles were explored in the experiment,so as to optimize the reaction environment to achieve the desired effect.In addition,we also tried to use other metal salts to react with DPS to deposit different types of metal nanoparticles.Pt and Ag are metals often used in nanomaterials.After being deposited on DPS,it has the potential for improvement in terms of catalysis and Raman spectroscopy.(3)After SEM and BET characterization,it was found that there are still huge spaces in the holes of Au-DPS that can be loaded with other substances,which provides structural support for the combination of photothermal treatment and chemotherapy to kill cancer cells.Au-DPS has good photothermal properties,and can be locally heated from room temperature to 50.1°C within 15 minutes in its low concentration suspension system.pDox is synthesized by covalently binding Dox to a poly(1-glutamic acid)glutamic acid side chain via a pH-sensitive linker.After loading in such as Au-DPS,its photothermal controllable release is realized.Further in vitro cell experiments verify that the combined effect of photothermal and chemotherapeutic drugs has a very significant effect on killing cancer cells.In addition,the absorption of light energy by Au-DPS will also promote the desorption of small molecules it adsorbs.Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry detection using 6 standard small peptides.With matrix-free CHCA,P14 R,Angiotensin II,and ACTH 18-39 were successfully detected with three particles.The experimental results show that the larger the pore size of porous silicon and the smaller the metal nanoparticles,the more sensitive the detection.For the detection of ACTH 18-39 standard peptides,the three particles showed lower detection limits than common organic matrices.Finally,the platform was used to study the glutathione mimic enzyme.The EDC/NHS modification method was used to modify the selenocysteine ??(Sec)with GPx active center to the surface of Au-DPS.The affinity of the active site Se with the substrate GSH and peroxide specifically accelerates the reaction.The related researches on catalytic activity and reaction kinetics were carried out.This multi-level structure of the nano-enzyme system provides new design ideas for the development of mimic enzymes.In summary,this thesis follows the basic rules of nanomaterial properties,and uses a synthetic disc-shaped porous silicon as a framework to prepare a matrix of gold nanoparticles with uniform properties,and realizes the concept of combined photothermal drugs to kill tumor cells,and improves The sensitivity of some small molecules using mass spectrometry was determined.Finally,a nanoenzyme system with glutathione-like peroxidase catalysis was constructed,and its properties and reaction mechanism were discussed.Therefore,it can be seen that DPS is a nanomaterial with multifunctionality and has broad application prospects.