Study On The Adhesion Characteristics Of Mussel Adhesive Protein And Preparation Of Anti-fouling Materials

Mussels are one of the most typical fouling organisms in the sea.They usually attach to ships and other underwater facilities by secreting adhesion protein,which would cause the corrosion of the facilities and increase fuel consumptions as a result.It is of great significance to investigate the adhesion behavior between mussel adhesion protein and the surface of various materials,explore the reason why the mussel adhesion protein has a strong adhesion effect and design materials that possess the abilities of anti-fouling.In this paper,three mussel adhesion adhesion proteins Mefp-3,Mfp-5,and Mefp-5 are taken as the study objects,and the adhesion force of the three proteins to different materials before and after the dopa modification is studied through the comparisons of atomic force spectroscopy.The quartz crystal microbalance（QCM-D）is adopted to analyze the adsorption and desorption process of adhesion proteins at different interfaces.Silane coupling agents including zwitterions,quaternary ammonium salts,and perfluorinated functional groups were used to modify polydimethylsiloxane（PDMS）on the surface to prepare anti-adhesive materials.Subsequently,anti-bacterial,anti-algae and anti-mussel protein tests are used to evaluate the anti-fouling performance.The study uses tyrosinase to dopa-oxidize the three mussel foot adhesion proteins of Mefp-3,Mfp-5,and Mefp-5.The oxidized protein is measured by ultraviolet spectroscopy to characterize the degree of dopa.After 12 hours of oxidation,the degree of dopainization of foot protein more than 57%.Modify the protein before and after dopaization to the surface of the atomic force probe,and use the above probe to test the adhesion force between the protein and different interfaces.The adhesion force of all the proteins on the mica is greater than the adhesion force on the silicon wafer;After dopaization,the adhesion of the protein increase,and the adhesion of Mfp-5 dopaized protein on the mica sheet increased the most,from 15 n N to 70n N.The adsorption and desorption experiments of mussel protein before and after dopaization are carry out with QCM-D.The adsorption frequency of dopa protein is greatly increase.The adsorption frequency is fit to obtain the protein adsorption quality per unit area of the chip.After Dopaization,the adsorption quality of Mfp-5 protein on the gold chip surface increase from 433 ng/cm² to 2258 ng/cm²,and the adsorption quality increase by 5 times.And the amount of desorption of dopaized protein is low.The adsorption of dopaized protein on the chip surface change from simple rigid adsorption to complex flexible adsorption.Sulfhydryl compounds with different functional groups are synthesized by Michael addition reaction,and then the hydrophilic zwitterion（sulfobetaine）and hydroxyl surface are constructe on the surface of the gold chip by the sulfhydryl group.The surface was charged with positively charged quaternary ammonium salt and low surface.Through QCM-D,we explore the adsorption and desorption of Mfp-5_Dopa on different surface modified chips.Studies show that the hydrophilic functional groups can form a dense hydration layer on the surface of the chip,so the protein adsorption capacity is the lowest.The quaternary ammonium cations also have a certain anti-protein adsorption capacity because the surface has the same charge as the protein.The perfluorinated surface protein adsorption capacity larger;but the desorption experiment results show that the low surface energy chip（surface energy 20.76 m N/m）modified by perfluorinated protein has strong decontamination ability.After washing,the surface protein adsorption frequency drops from 26 Hz to 15 Hz,and the protein desorption rate is 42%.However,the amount of protein desorption on the surface of the chip modified with hydrophilic functional groups is lower.The surface of the PDMS material was activated by a plasma surface treatment instrument,and then zwitterions,quaternary ammonium salt,and perfluorofunctional groups were modified on the surface of the activated material with a silane coupling agent.PDMS antifouling materials with hydrophilicity,positively charged surface and low surface energy are prepared respectively.Characterize the elemental composition and morphology of the material surface through X-ray photoelectron spectroscopy,scanning electron microscope,etc.,and explore the anti-fouling performance of different surface modified PDMS.The results show that the PDMS antifouling material modified with zwitterionic surface has the strongest antifouling performance,and the inhibition rate of the adhesion to Halamphora sp and the antibacterial rate of Escherichia coli reached more than 90%;and the anti-Mfp-5_Dopa protein ability was also reach more than 80%.The PDMS modified with quaternary ammonium salt has a positive charge that can destroy the cell structure,and the antibacterial rate against Staphylococcus aureus and Escherichia coli is above 80%.Studies have found that hydrophilic materials represented by zwitterions have excellent anti-protein adsorption and anti-fouling properties.