Adsorption and friction of Mussel Adhesive Protein (MAP) films under polarization (original) (raw)
Related papers
Mussel-Inspired Surface Chemistry for Multifunctional Coatings NIH Public Access
We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules. Methods for chemical modification of bulk material surfaces play central roles in modern chemical, biological, and materials sciences, and in applied science, engineering, and technology (1–4). The existing toolbox for the functional modification of material surfaces includes methods such as self-assembled monolayer (SAM) formation, functionalized silanes, Langmuir-Blodgett deposition, layer-by-layer assembly, and genetically engineered surface-binding peptides (5–9). Although widely implemented in research, many available methods have limitations for widespread practical use; specific examples include the requirement for chemical specificity between interfacial modifiers and surfaces (e.g., alkanethiols on noble metals and silanes on oxides), the use of complex instrumentation and limitations of substrate size and shape (Langmuir-Blodgett deposition), or the need for multistep procedures for implementation (layer-by-layer assembly and genetically engineered surface-binding peptides). Development of simple and versatile strategies for surface modification of multiple classes of materials has proven challenging, and few generalized methods for accomplishing this have been previously reported (10). Our approach is inspired by the adhesive proteins secreted by mussels for attachment to wet surfaces (11). Mussels are promiscuous fouling organisms and have been shown to attach to virtually all types of inorganic and organic surfaces (12), including classically adhesion-resistant materials such as poly(tetrafluoroethylene) (PTFE) (Fig. 1A). Clues to mussels' adhesive versatility may lie in the amino acid composition of proteins found near the plaque-substrate interface (Fig. 1, B to D), which are rich in 3,4-dihydroxy-L-phenylalanine (DOPA) and lysine amino acids (13). In addition to participating in reactions
ACS Applied Materials & Interfaces, 2015
Mussels survive by strongly attaching to a variety of different surfaces, primarily subsurface rocks composed of metal oxides, through the formation of coordinative interactions driven by protein-based catechol repeating units contained within their adhesive secretions. From a chemistry perspective, catechols are known to form strong and reversible complexes with metal ions or metal oxides, with the binding affinity being dependent on the nature of the metal ion. As a result, catechol binding with metal oxides is reversible and can be broken in the presence of a free metal ion with a higher stability constant. It is proposed to exploit this competitive exchange in the design of a new strategy for the formation, removal, and reformation of surface coatings and self-assembled monolayers (SAM) based on catechols as the adhesive unit. In this study, catechol-functionalized tri(ethylene oxide) (TEO) was synthesized as a removable and recoverable self-assembled monolayer (SAM) for use on oxides surfaces. Attachment and detachment of these catechol derivatives on a variety of surfaces was shown to be reversible and controllable by exploiting the high stability constant of catechol to soluble metal ions, such as Fe(III). This tunable assembly based on catechol binding to metal oxides represents a new concept for reformable coatings with applications in fields ranging from friction/wettability control to biomolecular sensing and antifouling.