Study On Antifouling And Anticorrosion Performance Of Hull Surfaces Modification By Antimicrobial Peptides

The attachment and colonization of marine fouling organisms to a wide range of surfaces such as ships,pipelines and aquaculture nets pose a range of hazards associated with human activities related to the sea and biofouling is a growing concern.However,traditional antifouling coatings contain heavy metal ions and are also highly toxic to non-target marine organisms,which is not in line with the concept of green antifouling,hence the need to develop an environmentally friendly broad-spectrum antifouling means.Antimicrobial peptides are biomolecules secreted by many organisms that can inhibit the adhesion of fouling organisms such as bacteria.Some of the antimicrobial peptides have excellent cytocompatibility and high affinity and can be used as potential materials for modifying ship surfaces.In this thesis,304 stainless steel(SS)was used as the substrate for the study,and the surface of the metal material was modified with the antimicrobial peptides obtained through screening and optimization to obtain modified bio-organic metal materials.The physical and chemical properties of the sample surface were characterized using characterization instruments,and Vibrio natriegens(V.natriegens)and Phaeodactylum tricornutum(P.tricornutum)were selected to assess the antifouling properties of the sample surface,and the corrosion resistance of the sample was also evaluated for different periods of immersion in the V.natriegens culture solution.The study is aimed at establishing a new means of antifouling and anticorrosion on the surface of ships through continuous optimization of the modification methods.The main research elements are as follows.1.Dopamine/PEI/SiO2/antibacterial peptide multi-modified surfaceNanocomposite surfaces SS-DA/PEI/SiO2 were prepared using dopamine(DA),polyethyleneimine(PEI)and silicon dioxide(SiO2)co-deposited to modify DA-modified 304 SS surfaces,and SS-DA/PEI/SiO2-M composite surfaces were prepared by grafting antimicrobial peptides(AMPs)MAG Ⅱ.The morphological structure,physicochemical properties,cytocompatibility,antifouling and anticorrosion properties of SS-DA/PEI/SiO2 and SS-DA/PEI/SiO2-M surfaces were tested and investigated in detail.The results showed that the DA/PEI/SiO2/AMPs composite coatings were successfully prepared on the 304 SS surfaces,and both modified surfaces showed excellent cytocompatibility.The results of antifouling experiments showed that the antibacterial efficiency of SS-DA/PEI/SiO2 surfaces before and after AMPs modification reached 78.39%and 95.90%,and the successful grafting of AMPs improved the antifouling performance of the modified sample surfaces.Electrochemical and stability tests showed that the modified sample surfaces exhibited good corrosion resistance and antifouling stability.2.Surface modification by dopamine and antimicrobial peptideBased on the above study,antifouling surface SS-DA-TB was prepared by grafting the antimicrobial peptide Turgencin BMox2(TB)onto 304 SS surface with DA as a coupling agent by optimizing the reaction steps and improving the antimicrobial peptide.The morphological characteristics and physicochemical properties of the sample surfaces before and after modification were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),Contact angle measurement(CA),Three-dimensional optical microscopy,Ellipsometric polarization and Atomic force microscopy(AFM).The results showed that the antimicrobial peptides were successfully grafted onto the 304 SS surface and changed the surface morphology and wettability of the samples.The excellent cytocompatibility of the antimicrobial peptide TB was demonstrated by the co-culture of 293T and E11 cells with the antimicrobial peptide TB.Fouling biological attachment tests have demonstrated the excellent antifouling performance of SS-DA-TB,showing 99.85%and 67.93%inhibition of V.natriegens and P.tricornutum.In addition,electrochemical performance tests indicated that SS-DA-TB had good corrosion resistance even after 14 days of immersion in V.natriegens culture solution.3.Antibacterial peptide derivatives modified surfacesBased on the above research,we further optimized the reaction steps and improved the antimicrobial peptide,and synthesized an antimicrobial peptide derivative DP by using AMPs extracted from marine organisms and dopamine under weak acid conditions,and then used it to modify 304 SS to prepare antifouling surface SS-DP.Mass spectrometry analysis confirmed the synthesis reaction of DP,and the cytocompatibility test results showed that the antimicrobial peptide derivative DP had excellent cytocompatibility.FTIR,XPS,AFM,CA and 3D optical profilometry demonstrated the successful grafting of DP onto the 304 SS surface.Using fouling bio adhesion tests demonstrated the excellent antifouling ability of the DP-treated 304 SS surfaces,which exhibited 97.78%and 90.01%adhesion inhibition against V.natriegens and P.tricornutum.In addition,electrochemical performance and stability test results indicated that the prepared SS-DP surface had excellent corrosion resistance and antifouling stability.The results of this thesis can provide a novel green antifouling and anticorrosion strategy for the marine industry field and other related fields.