Construction And Biofunctionalization Application For Mussel Biomimetic Poly-caffeic Acid Coating

Surface modification is an important research component in the development and design of interventional biomaterials and devices.Although the current surface modification strategies are very diverse and mature,such as self-assembled monolayers,layer-by-layer self-assembly,initiated chemical vapor deposition,plasma treatment,Langmuir-Blodgett deposition,protein-assembled coatings,etc.,these methods are still limited in practical application due to problems such as substrate material limitations,key equipment limitations,and complex processes.Therefore,there is still a need to develop a versatile modification platform that is simple and applicable to most materials.In the study of mussel adhesion mechanism,the catechol structure was found to be the key moiety for its excellent adhesion property.Based on the mussel adhesion inspiration,researchers developed polydopamine coatings with catechol derivatives of dopamine,which in addition to broad-spectrum adhesion,can also be used as a secondary modification platform for further functional surface design.Based on the mussel adhesion and related surface modification studies,a novel bio-functional modification platform Poly-Caffeic Acid(PCA)coating was developed in this thesis by oxidative polymerization.The successful preparation of the coating was illustrated by Fourier infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and liquid chromatography-mass spectrometry,etc.,and found that during oxidative self-polymerization,caffeic acid formed benzoquinone compounds and dimerized was formed by benzene ring coupling,which were assembled on the material to form coating through chemical interactions such as hydrogen bonding andπ-πstacking,resulting in polymers with complex compositions.The relevant performance evaluation indicated that PCA coating has a strong ability to modify different materials;immersion experiments showed that PCA coating has good stability in the phosphate buffer solution;hemolysis test,platelet adhesion,and ex-vivo circulation experiments showed that PCA coating can improve the hemocompatibility of 316L stainless steel to some extent.Developing pro-endothelial cell adhesion surface based on PCA coating.The successful Construction of the functional coating was verified by FTIR and XPS;the peptide grafting density on the coating was 212.90 ng/cm~2 by the dissipative quartz crystal microbalance;In vitro vascular cell culture experiments demonstrated that the coating is selectively specific for endothelial cells,and endothelial cells can achieve rapid adhesion on the coating.Developing antibacterial surface based on PCA coating.The successful construction of Ag-containing antibacterial coating was illustrated by XPS and X-ray diffractometer characterization;according to the results of inductively coupled plasma-mass spectrometry,the Ag density on the coating can be regulated by the Ag~+concentration;the relevant experiments such as plate colony counting showed that the antimicrobial effect of the coating was related to the concentration of Ag~+used.The coating can effectively kill both Gram-negative and Gram-positive bacteria represented by E.coli and S.epidermidi,when the concentration of Ag~+is higher than 0.001 mg/m L,and has broad-spectrum antibacterial performance;In vitro cytotoxicity evaluation showed that the coating constructed with high concentration of Ag~+was cytotoxic.Combined with the antimicrobial experiments and cytocompatibility evaluation,a better process for the antibacterial coating could be successfully screened.The above results indicate that PCA coating developed based on the principle of mussel adhesion has the advantages of simple preparation,mild conditions,the strong ability of modification for different materials,and simple functionalization secondary modification operation,which has the potential as a platform for biofunctionalization modification.