The Preparation And Biological Application Of Ag@PS-CHO Core-shell Functional Microspheres

In this paper,the functional polymer microsphere with aldehyde-base on PS surface was designed first.Based on the Lewis-Meyer equation,the influencing factors of microsphere synthesis and the control of copolymerization were studied.The process of copolymerization of microspheres and influencing factors were discussed.With the help of the reductive action of functionalized PS microspheres' surface active groups,the silver nanoparticles were reduced to the surface of the microspheres.The influencing factors on the particle size of the silver nanoparticles were studied,and the influence of the microsphere coverage degree was discussed.The use of prepared core-shell microspheres to detect a series of concentrations of protein solution,using a variety of detection methods to detect low and very low concentrations of protein,building a series of mathematical model of protein concentration and detection strength.The results can increase the detection limit of trace protein and improve the rapid detection response.The results of the study constructed ultra-sensitive protein detection devices and conducted preliminary research and discussion on rapid detection of biomedical protein concentrations.The main research content includes the following aspects:(1)With styrene,acrolein as monomer,polyvinylpyrrolidone as dispersant,ethanol/water as dispersion medium,azobisisobutyronitrile and dibenzoyl peroxide as initiators,different particle sizes of PS-CHO functional microspheres were prepared by dispersion polymerization.The PS-CHO microspheres were characterized by modern instrument testing techniques.The particle size and monodispersity of microspheres under different polymerization conditions were studied.The effects of monomer ratio,dispersant dosage,initiator type,initiator dosage,reaction temperature and polarity of reaction medium on the particle size and monodispersity of PS functionalized microspheres were investigated.The results show that the amount of initiator and the temperature of the reaction system increase the diameter of the microspheres.In the copolymerization composition,the amount of polar monomer increases,the amount of dispersant increases,and the polarity of the reaction medium increases.(2)The aldehyde-functionalized polystyrene microspheres were used as carriers to achieve the directional reduction and fixation of silver nanoparticles on the surface of the microspheres.Ag@PS core-shell microspheres were prepared by chemical reduction deposition using the reducibility of aldehyde groups on the surface of the microspheres.By adjusting the ratio of monomers,the amount of silver nitrate,the amount of initiator,the reaction temperature and the reaction time,the size and distribution of the silver particles loaded on the surface of the microspheres were studied,and silver nanoparticles coated with different shapes and sizes were constructed.The control mechanisms of the formation of microspheres with different surface topography were discussed.The results show that the particle size of the silver nanoparticles coated on the surface of the microspheres is 6 nm,9 nm,13 nm,20 nm,30nm and 40 nm,and the coating degree of the silver nanoparticles is controllable.The Ag@PS core-shell microspheres can be preserved in air for 60 days at room temperature,and still have good silver nanoparticle properties.The introduction of surface aldehyde groups provides a stable chemical environment for the silver nanoshell layer,and has a regulatory effect on the degree of nanoparticle coating,particle size and morphology of the nanoparticles.(3)Using a variety of modern testing methods,the application of Ag@PS core-shell functional microspheres in trace protein detection was studied.Adsorption of proteins on prepared Ag@PS microspheres,detection of higher concentrations of proteins using Coomassie brilliant blue,and surface-enhanced Raman effects of Ag@PS and electrochemical and current-voltage responses of Ag@PS,detection is extremely low.A device for efficiently and rapidly detecting low-concentration protein is prepared.The results showed that using Coomassie's method to detect protein concentration to 10"6mg/mL,protein concentration with surface Raman enhancement can reach 10-10mol/L,while the electrochemical response to detect protein concentration to 10-14mol/L.The sensitivity of protein detection has increased by 4 orders of magnitude.The limit of detection has been increased by 8 orders of magnitude compared with the lower limit of protein detection of 10-6mol/L that has been reported in related literature.A preliminary exploration was made on trace detection and ultrasensitive detection.