Adhesion of Mussel Foot Protein-3 to TiO2 Surfaces: the Effect of pH

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• 作者：Jing Yu ; Wei Wei ; Matthew S. Menyo ; Admir Masic ; J. Herbert Waite ; Jacob N. Israelachvili
• 刊名：Biomacromolecules
• 出版年：2013
• 出版时间：April 8, 2013
• 年：2013
• 卷：14
• 期：4
• 页码：1072-1077
• 全文大小：339K
• 年卷期：v.14,no.4(April 8, 2013)
• ISSN：1526-4602

文摘

The underwater adhesion of marine mussels relies on mussel foot proteins (mfps) rich in the catecholic amino acid 3,4-dihydroxyphenylalanine (Dopa). As a side chain, Dopa is capable of strong bidentate interactions with a variety of surfaces, including many minerals and metal oxides. Titanium is among the most widely used medical implant material and quickly forms a TiO₂ passivation layer under physiological conditions. Understanding the binding mechanism of Dopa to TiO₂ surfaces is therefore of considerable theoretical and practical interest. Using a surface forces apparatus, we explored the force鈥揹istance profiles and adhesion energies of mussel foot protein 3 (mfp-3) to TiO₂ surfaces at three different pHs (pH 3, 5.5 and 7.5). At pH 3, mfp-3 showed the strongest adhesion force on TiO₂, with an adhesion energy of 鈭?.0 mJ/m². Increasing the pH gives rise to two opposing effects: (1) increased oxidation of Dopa, thus, decreasing availability for the Dopa-mediated adhesion, and (2) increased bidentate Dopa-Ti coordination, leading to the further stabilization of the Dopa group and, thus, an increase in adhesion force. Both effects were reflected in the resonance-enhanced Raman spectra obtained at the three deposition pHs. The two competing effects give rise to a higher adhesion force of mfp-3 on the TiO₂ surface at pH 7.5 than at pH 5.5. Our results suggest that Dopa-containing proteins and synthetic polymers have great potential as coating materials for medical implant materials, particularly if redox activity can be controlled.