超親水雙離子材料具有和聚乙二醇(polyethylene glycol, PEG)相同的抗生物汙染(anti-biofouling)特性，因此被應用於生醫材料的表面修飾。在這研究中，我們提出一種建構抗非特異性吸附表面的新方法，以Michael addition方式，將雙離子材料接枝於聚多巴胺表面，使其具有1. 超親水性；2. 抵抗生物吸附；3. 可用於多樣基材表面修飾；4. 製備簡單與5. 多功能性。多巴胺因同時具有鄰苯二酚和胺基被證實能黏附於各種基材表面，形成聚多巴胺層，此化學結構中，俱有一級胺與二級胺官能基，可與甲基丙烯酸磺基甜菜鹼(Sulfobetaine methacrylate, SBMA)和丙烯醯胺磺基甜菜鹼(Sulfobetaine acrylamide, SBAA)雙離子單體藉由Michael addition接枝於表面，達到良好的抗生物汙染特性。
因此這項研究要先形成帶有大量的活性胺基官能基的聚多巴胺表面，並且藉由Michael addition反應使胺基和帶有乙烯基單體進行1，4加成，而將單體接枝於聚多巴胺表面，並應用於各種基板修飾。這裡我們比較三種抗吸附單體分別為SBAA、SBMA和聚乙二醇單甲醚甲基丙烯酸酯(poly(ethylene glycol) methacrylate, PEGMA)，並接枝於聚多巴胺表面使其達抗生物汙染之特性。利用水接觸角和X射線光電子能譜了解單體接枝於聚多巴胺的親水性質、表面元素組態和鍵結機制。並藉由綠膿桿菌、大腸桿菌和表皮葡萄球菌細菌貼附，比較不同密度的丙烯醯胺基和甲基丙烯酸接枝於聚多巴胺和具有不同抗生物汙染程度。其中，在XPS結果，於pDA18的塗層上接枝，其效果比於pDA3有更好的單體接枝率。在pDA18 SBAA修飾條件下，表面水接觸角可小於5度；細菌貼附實驗結果，可分別抵抗93%、94.2%和98%的綠膿桿菌、大腸桿菌和表皮葡萄球菌的貼附。最後，利用聚多胺還原銀奈米粒子特性結合抗生物汙染塗層，發展出同時具有銀奈米粒子殺菌功效和SBAA抗細菌貼附的複合式塗層，此表面可抵抗90%大腸桿菌貼附，而貼附於表面的細菌98%為死菌。本研究的最終目的是發展了一種新的修飾方法，可於各種機材表面進行改質而達到抗生物汙染的功能，並且開發多功能生物界面，並期待應用於醫療器材表面塗層，以提升其生物相容性與使用安全性。

Superhydrophilic zwitterionic materials are recognized as a new class of antifouling materials as an alternative to poly(ethylene glycol) (PEG) for uses of biomedical device in complex conditions. In this study, we aim to develop establish a new grafting method based on polydopamine via Michael addition approach to avoid nonspecific adsorption. The developed coatings exhibit multiple functions, including 1. superhydrophilicity, 2. antifouling properties, 3. substrate-independent modification, 4. facile preparation, and 5. versatility. Dopamine contains both amine and catechol functional groups, which enables to deposit on all kinds of substrates. Sulfobetaine acrylamide (SBAA), Sulfobetaine methacrylate (SBMA) are zwitterionic monomer, which have been demonstrated with their excellent antifouling properties in a polymer brush form. Therefore, the purpose of this work is to graft SB moieties onto polydopamine (pDA) coatings containing abundant amine groups to react with vinyl groups of monomers via the Michael addition to achieve substrate-independent surface modification. We employed three monomers, i.e. SBAA, SBMA, and poly(ethylene glycol) methacrylate (PEGMA) to react with pDA. To develop an antifouling coating, an appropriate preparation strategy is highly determinant for the sufficient grafting density of fouling-resistant groups, i.e. SB and PEG. Surface characterization techniques with the contact angle goniometer, and X-ray photoelectron spectroscopy (XPS) were utilized to explore the surface hydration, chemical states and bonding mechanism of the grafted pDA films. To examine the antifouling properties of the coatings, they were brought to contact with bacteria solutions containing P. aeruginosa, E. coli, and S. epidermidis followed by observing under fluorescence optical microscope. The results indicated that the fouling levels were determined by the grafting densities of monomers on pDA surfaces. In XPS result, pDA18 coating condition grafting densities of monomer is higher than pDA3 coating condition. In pDA18 SBAA coating condition, the contact angle is less than 5 degree. According to the bacterial anti-fouling results, pDA18 SBAA coating can resistance 93%, 94.2% and 98% of P. aeruginosa, E. coli, and S. epidermidis, respectively. This can be modulated by the reaction activities of methacrylate and acrylamide with amine groups on pDA. In addition, silver particles formed in the pDA layers were applied to kill 98% adsorbed bacteria, enabling multiple functions of adlayers. The work paves a new avenue to developing the new functional bioinspired antifouling interface in a substrate-independent fashion.

[1] A. Vertes, V. Hitchins, and K. S. Phillips, "Analytical Challenges of Microbial Biofilms on Medical Devices," Analytical Chemistry, vol. 84, pp. 3858-3866, May 2012.
[2] R. D. Scott, "The direct medical costs of healthcare-associated infections in U. S. hospitals and the benefits of prevention " Centers for Disease Control and Infection, 2009.
[3] M. Salwiczek, Y. Qu, J. Gardiner, R. A. Strugnell, T. Lithgow, K. M. McLean, et al., "Emerging rules for effective antimicrobial coatings," Trends in Biotechnology, vol. 32, pp. 82-90, Feb 2014.
[4] T. A. Horbett, "The role of adsorbed proteins in animal cell adhesion," Colloids and Surfaces B: Biointerfaces, vol. 2, pp. 225-240, 1994.
[5] I. Banerjee, R. C. Pangule, and R. S. Kane, "Antifouling Coatings: Recent Developments in the Design of Surfaces That Prevent Fouling by Proteins, Bacteria, and Marine Organisms," Advanced Materials, vol. 23, pp. 690-718, Feb 2011.
[6] D. A. Herold, K. Keil, and D. E. Bruns, "Oxidation of polyethylene glycols by alcohol dehydrogenase," Biochemical Pharmacology, vol. 38, pp. 73-76, 1989.
[7] A. P. Ryle, "Behaviour of Polyethylene Glycol on Dialysis and Gel-filtration," Nature, vol. 206, p. 1256, 1965.
[8] A. Abuchowski, T. van Es, N. C. Palczuk, and F. F. Davis, "Alteration of immunological properties of bovine serum albumin by covalent attachment of polyethylene glycol," J Biol Chem, vol. 252, pp. 3578-81, 1977.
[9] C. G. S. Zalipsky, A. Zilkha, "Attachment of drugs to polyethylene glycols," European Polymer Journal, vol. 19, pp. 1177-1183, 1983.
[10] S. M. Nagaoka, Y.; Takiuchi, H.; Yokota, K.; Tanzawa, H.; Nishiumi, S.,, Polymers as Biomaterials. New York: Plenum Press, 1985.
[11] X. Y. Zhu and G. Athena, "The Critical Role of Surface Chemistry in Protein Microarrays," in Functional Protein Microarrays in Drug Discovery, ed: CRC Press, pp. 53-71, 2007.
[12] C. G. P. H. Schroen, M. A. C. Stuart, K. van der Voort Maarschalk, A. van der Padt, and K. van't Riet, "Influence of Preadsorbed Block Copolymers on Protein Adsorption: Surface Properties, Layer Thickness, and Surface Coverage," Langmuir, vol. 11, pp. 3068-3074, 1995.
[13] J. M. Harris, Poly(ethylene glycol) chemistry : biotechnical and biomedical applications. Plenum Press: New York, 1992.
[14] R. E. Holmlin, X. Chen, R. G. Chapman, S. Takayama, and G. M. Whitesides, "Zwitterionic SAMs that Resist Nonspecific Adsorption of Protein from Aqueous Buffer," Langmuir, vol. 17, pp. 2841-2850, 2001.
[15] J. B. U. Reece, Lisa A.; Cain, Michael L.; Wasserman, Steven A.; Minorsky, Peter V.; Jackson, Robert B, Campbell Biology. Boston: Benjamin Cummings, 2011.
[16] S. J. Singer and G. L. Nicolson, "The fluid mosaic model of the structure of cell membranes," Science, vol. 175, pp. 720-31, 1972.
[17] A. L. Lewis, "Phosphorylcholine-based polymers and their use in the prevention of biofouling," Colloids Surf B Biointerfaces, vol. 18, pp. 261-275, 2000.
[18] Y. Kadoma, N. Nakabayashi, E. Masuhara, and J. Yamauchi, "Synthesis and Hemolysis Test of the Polymer Containing Phosphorylcholine Groups," KOBUNSHI RONBUNSHU, vol. 35, pp. 423-427, 1978.
[19] K. Ishihara, T. Ueda, and N. Nakabayashi, "Preparation of Phospholipid Polylners and Their Properties as Polymer Hydrogel Membranes," Polym J, vol. 22, pp. 355-360, 1990.
[20] W. Feng, S. Zhu, K. Ishihara, and J. L. Brash, "Adsorption of Fibrinogen and Lysozyme on Silicon Grafted with Poly(2-methacryloyloxyethyl Phosphorylcholine) via Surface-Initiated Atom Transfer Radical Polymerization," Langmuir, vol. 21, pp. 5980-5987, 2005.
[21] Z. Zhang, S. Chen, Y. Chang, and S. Jiang, "Surface Grafted Sulfobetaine Polymers via Atom Transfer Radical Polymerization as Superlow Fouling Coatings," The Journal of Physical Chemistry B, vol. 110, pp. 10799-10804, 2006.
[22] Y. Chang, S. C. Liao, A. Higuchi, R. C. Ruaan, C. W. Chu, and W. Y. Chen, "A Highly stable nonbiofouling surface with well-packed grafted zwitterionic polysulfobetaine for plasma protein repulsion," Langmuir, vol. 24, pp. 5453-5458, May 2008.
[23] W.-F. Lee and C.-C. Tsai, "Synthesis and solubility of the poly(sulfobetaine)s and the corresponding cationic polymers: 1. Synthesis and characterization of sulfobetaines and the corresponding cationic monomers by nuclear magnetic resonance spectra," Polymer, vol. 35, pp. 2210-2217, 1994.
[24] J. Ning, K. Kubota, G. Li, and K. Haraguchi, "Characteristics of zwitterionic sulfobetaine acrylamide polymer and the hydrogels prepared by free-radical polymerization and effects of physical and chemical crosslinks on the UCST," Reactive and Functional Polymers, vol. 73, pp. 969-978, 2013.
[25] J. Sun, F. Zeng, H. L. Jian, and S. Z. Wu, "Conjugation with Betaine: A Facile and Effective Approach to Significant Improvement of Gene Delivery Properties of PEI," Biomacromolecules, vol. 14, pp. 728-736, Mar 2013.
[26] R. S. Kane, P. Deschatelets, and G. M. Whitesides, "Kosmotropes Form the Basis of Protein-Resistant Surfaces," Langmuir, vol. 19, pp. 2388-2391, 2003.
[27] Z. Zhang, T. Chao, S. Chen, and S. Jiang, "Superlow Fouling Sulfobetaine and Carboxybetaine Polymers on Glass Slides," Langmuir, vol. 22, pp. 10072-10077, 2006.
[28] Z. Zhang, S. F. Chen, and S. Y. Jiang, "Dual-Functional Biomimetic Materials: Nonfouling Poly(carboxybetaine) with Active Functional Groups for Protein Immobilization," Biomacromolecules, vol. 7, pp. 3311-3315, Dec 2006.
[29] J. S. Wang and K. Matyjaszewski, "Controlled living radical polymerization - atom-transfer radical polymerization in the presence of transition-metal complexes," Journal of the American Chemical Society, vol. 117, pp. 5614-5615, May 1995.
[30] K. Matyjaszewski and J. H. Xia, "Atom transfer radical polymerization," Chemical Reviews, vol. 101, pp. 2921-2990, Sep 2001.
[31] J. Pyun, T. Kowalewski, and K. Matyjaszewski, "Synthesis of Polymer Brushes Using Atom Transfer Radical Polymerization," Macromolecular Rapid Communications, vol. 24, pp. 1043-1059, 2003.
[32] Y. Li, A. J. Keefe, M. Giarmarco, N. D. Brault, and S. Jiang, "Simple and Robust Approach for Passivating and Functionalizing Surfaces for Use in Complex Media," Langmuir, vol. 28, pp. 9707-9713, 2012.
[33] R. G. Nuzzo and D. L. Allara, "Adsorption of bifunctional organic disulfides on gold surfaces," Journal of the American Chemical Society, vol. 105, pp. 4481-4483, 1983.
[34] J. C. Love, L. A. Estroff, J. K. Kriebel, R. G. Nuzzo, and G. M. Whitesides, "Self-Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology," Chemical Reviews, vol. 105, pp. 1103-1170, 2005.
[35] C. J. Huang, "Surface ener Engineering," 2013.
[36] H. Lee, S. M. Dellatore, W. M. Miller, and P. B. Messersmith, "Mussel-Inspired Surface Chemistry for Multifunctional Coatings," Science (New York, N.Y.), vol. 318, pp. 426-430, 2007.
[37] H. Lee, N. F. Scherer, and P. B. Messersmith, "Single-molecule mechanics of mussel adhesion," Proceedings of the National Academy of Sciences, vol. 103, pp. 12999-13003, 2006.
[38] J. H. Waite and X. Qin, "Polyphosphoprotein from the adhesive pads of Mytilus edulis," Biochemistry, vol. 40, pp. 2887-93, Mar 2001.
[39] Q. Ye, F. Zhou, and W. Liu, "Bioinspired catecholic chemistry for surface modification," Chem Soc Rev, vol. 40, pp. 4244-58, Jul 2011.
[40] S. Zürcher, D. Wäckerlin, Y. Bethuel, B. Malisova, M. Textor, S. Tosatti, et al., "Biomimetic Surface Modifications Based on the Cyanobacterial Iron Chelator Anachelin," Journal of the American Chemical Society, vol. 128, pp. 1064-1065, 2006.
[41] E. Amstad, T. Gillich, I. Bilecka, M. Textor, and E. Reimhult, "Ultrastable Iron Oxide Nanoparticle Colloidal Suspensions Using Dispersants with Catechol-Derived Anchor Groups," Nano Letters, vol. 9, pp. 4042-4048, 2009.
[42] X. Fan, L. Lin, J. L. Dalsin, and P. B. Messersmith, "Biomimetic Anchor for Surface-Initiated Polymerization from Metal Substrates," Journal of the American Chemical Society, vol. 127, pp. 15843-15847, 2005.
[43] B. Malisova, S. Tosatti, M. Textor, K. Gademann, and S. Zürcher, "Poly(ethylene glycol) Adlayers Immobilized to Metal Oxide Substrates Through Catechol Derivatives: Influence of Assembly Conditions on Formation and Stability," Langmuir, vol. 26, pp. 4018-4026, 2010.
[44] G. Li, G. Cheng, H. Xue, S. Chen, F. Zhang, and S. Jiang, "Ultra low fouling zwitterionic polymers with a biomimetic adhesive group," Biomaterials, vol. 29, pp. 4592-4597, 2008.
[45] E. Faure, C. Falentin-Daudre, C. Jerome, J. Lyskawa, D. Fournier, P. Woisel, et al., "Catechols as versatile platforms in polymer chemistry," Progress in Polymer Science, vol. 38, pp. 236-270, Jan 2013.
[46] D. R. Dreyer, D. J. Miller, B. D. Freeman, D. R. Paul, and C. W. Bielawski, "Elucidating the Structure of Poly(dopamine)," Langmuir, vol. 28, pp. 6428-6435, Apr 2012.
[47] S. Hong, Y. S. Na, S. Choi, I. T. Song, W. Y. Kim, and H. Lee, "Non-Covalent Self-Assembly and Covalent Polymerization Co-Contribute to Polydopamine Formation," Advanced Functional Materials, vol. 22, pp. 4711-4717, Nov 2012.
[48] M. J. LaVoie, B. L. Ostaszewski, A. Weihofen, M. G. Schlossmacher, and D. J. Selkoe, "Dopamine covalently modifies and functionally inactivates parkin," Nature Medicine, vol. 11, pp. 1214-1221, Nov 2005.
[49] P. F. Li, X. M. Cai, D. Wang, S. C. Chen, J. Yuan, L. Li, et al., "Hemocompatibility and anti-biofouling property improvement of poly(ethylene terephthalate) via self-polymerization of dopamine and covalent graft of zwitterionic cysteine," Colloids and Surfaces B-Biointerfaces, vol. 110, pp. 327-332, Oct 2013.
[50] H. Lee, J. Rho, and P. B. Messersmith, "Facile Conjugation of Biomolecules onto Surfaces via Mussel Adhesive Protein Inspired Coatings," Advanced Materials, vol. 21, pp. 431, Jan 2009.
[51] S. Saidin, P. Chevallier, M. R. Abdul Kadir, H. Hermawan, and D. Mantovani, "Polydopamine as an intermediate layer for silver and hydroxyapatite immobilisation on metallic biomaterials surface," Materials Science and Engineering: C, vol. 33, pp. 4715-4724, 2013.
[52] T. S. Sileika, H. D. Kim, P. Maniak, and P. B. Messersmith, "Antibacterial Performance of Polydopamine-Modified Polymer Surfaces Containing Passive and Active Components," Acs Applied Materials & Interfaces, vol. 3, pp. 4602-4610, Dec 2011.
[53] M. Liu and M. P. Sibi, "Recent advances in the stereoselective synthesis of β-amino acids," Tetrahedron, vol. 58, pp. 7991-8035, 2002.
[54] B. C. Ranu and S. Banerjee, "Significant rate acceleration of the aza-Michael reaction in water," Tetrahedron Letters, vol. 48, pp. 141-143, Jan 2007.
[55] X. F. Song, L. F. Hu, D. H. Li, L. Chen, Q. Q. Sun, P. Zhou, et al., "Electrical level of defects in single-layer two-dimensional TiO2," Scientific Reports, vol. 5, p. 15989, 2015.
[56] R. A. Zangmeister, T. A. Morris, and M. J. Tarlov, "Characterization of Polydopamine Thin Films Deposited at Short Times by Autoxidation of Dopamine," Langmuir, vol. 29, pp. 8619-8628, 2013.
[57] K. Surendra, N. S. Krishnaveni, R. Sridhar, and K. R. Rao, "β-Cyclodextrin promoted aza-Michael addition of amines to conjugated alkenes in water," Tetrahedron Letters, vol. 47, pp. 2125-2127, 2006.
[58] R. Yang, X. R. Yang, D. F. Evans, W. A. Hendrickson, and J. Baker, "Scanning tunneling microscopy images of poly(ethylene oxide) polymers: evidence for helical and superhelical structures," The Journal of Physical Chemistry, vol. 94, pp. 6123-6125, 1990.
[59] G. Cheng, Z. Zhang, S. Chen, J. D. Bryers, and S. Jiang, "Inhibition of bacterial adhesion and biofilm formation on zwitterionic surfaces," Biomaterials, vol. 28, pp. 4192-4199, 2007.
[60] P. Kingshott, J. Wei, D. Bagge-Ravn, N. Gadegaard, and L. Gram, "Covalent Attachment of Poly(ethylene glycol) to Surfaces, Critical for Reducing Bacterial Adhesion," Langmuir, vol. 19, pp. 6912-6921, 2003.
[61] W. Zhang, F. K. Yang, Y. Han, R. Gaikwad, Z. Leonenko, and B. Zhao, "Surface and Tribological Behaviors of the Bioinspired Polydopamine Thin Films under Dry and Wet Conditions," Biomacromolecules, vol. 14, pp. 394-405, 2013.
[62] J. L. Dalsin, L. Lin, S. Tosatti, J. Vörös, M. Textor, and P. B. Messersmith, "Protein Resistance of Titanium Oxide Surfaces Modified by Biologically Inspired mPEG−DOPA," Langmuir, vol. 21, pp. 640-646, 2005.