Zwitterion Polymer Functionalized Gold Nanoparticles And Its Adsorption Study On The Resistance Of Protein

Endowing nanoparticles with high anti-fouling property is essential to apply them in biological system.As a kind of the most studied functional nanomaterials,Gold nanoparticles?GNPs?have een widely applied in biomedical fields,such as the biological monitoring,tumor imaging and cancer treatment due to their unique optical,chemical and electrical properties,as well as good stability,easy surface modification and biocompatibility etc.However,the surfaceof GNPs is easy to adsorb protein as a result of poor biocompatibility and low application effect under physiological environment.To improve the applicability of GNPs,an effective way is the introduction of impedance material on their surface,forming an isolation layer between the GNPs and the protein to inhibitthe adsorption of protein.Zwitterionic polymershave attracted much attention due to theirexcellent property of anti-protein adsorption in recent years.In this paper,we used poly sulfobetainemethaerylate?PSBMA?as impedance material,and then grafted on GNPs surface to study it.In this case,anti-fouling property was characterized by means of a sequence of method through bovine serum albumin?BSA?as the protein model.The results showed that the protein adsorption of GNPs was greatly reduced by special polymer long chain and zwitterionic structure of PSBMA.Firstly,PSBMA was firstly obtained by RAFT polymerizationand then coated gold nanoparticles to prepare PSBMA-@-GNPs via the strong binding between the thiol at end groups of polymer and gold.The structure of PSBMA was characterized by nuclear magnetic hydrogen spectrum?¹HNMR?,carbon nuclear magnetic resonance spectroscopy(¹³C-NMR)and gel permeation chromatography?GPC?.The“core-shell”structure of PSBMA-@-GNPs was investigated by UV-vis spectra,dynamic light scattering?DLS?and transmission electron microscopy?TEM?and determined a good dispersion of PSBMA-@-GNPs.Secondly,the number of BSA adsorption on the surfaceof PSBMA-@-GNPs was determined under different parameters including time,temperature and initial concentration.The optimum parameterswere obtained.Then,a series of characterization methods,such as ultraviolet spectrophotometer,fluorescence quenching,BCA kit and SDS-page gel electrophoresis was used to compare the quantity of BSA on GNPs,PSBMA-@-GNPs and PEG-@-GNPs.The results showed as follows:The BCA kit method was used to determine the surface protein adsorption percentage is 33.0%,8.5%and 7.0%of GNPs,PEG-@-GNPs and PSBMA-@-GNPs,respectively.SDS-PAGE gel electrophoresis method was used to determine the surface protein adsorption percentage is 29.0%,10.0%and 3.0%of GNPs,PEG-@-GNPs and PSBMA-@-GNPs,respectively.The anti-fouling property of PSBMA has been confirmed through above experiments.The surface modification of PSBMA established an effective strategy for the application of GNPs in drug carriers,biometrics,cancer detection and other fields.