Mussel adhesive protein inspired coatings: a versatile method to fabricate silica films on various surfaces

Abstract

A simple and versatile biomimetic strategy for the fabrication of silica films on a variety of substrates including gold, polystyrene and silicon wafers was developed using nanogram amounts per cm 2 of silicatein. The strategy exploits the adhesive property of 3,4-dihydroxyphenylalanine (DOPA) and a decapeptide (Ala-Lys-Pro-Ser-Tyr-DHP-Hyp-Thr-DOPA-Lys), important components of mussel adhesive proteins, to modify the surface of substrates. DOPA molecules polymerize to poly(DOPA) and the decapeptide forms thin films on gold substrates at pH 8.5, rendering the substrate compatible for silicatein immobilization. Nearly 50 ng cm À2 of silicatein is immobilized on poly(DOPA) and decapeptide coated surfaces where these polymer films act as ''cushion'' to protect the active structure and maintain the activity of the largely chemically adsorbed silicatein at ca. 95% of that experienced in solution. Uniform silica films of thickness 130-140 nm and roughness 12-14.5 nm were fabricated on coated gold surfaces. Evidence to show that this method is also applicable for the fabrication of uniform silica films on polystyrene and silicon substrates over multiple length scales in an economical way is also presented.

Surface engineering of polymer membranes via mussel-inspired chemistry

“…9) [71,139]. Another work used silicatein-α-protein as an aminecontaining agent to construct the silica-coated surfaces [140]. On the other hand, both the abundant hydroxyl groups and well-defined surface morphologies endow the silica-decorated membranes outstanding wettability and underwater superoleophobicity, which can be employed in oil-in-water emulsion separation [141].…”

High Ionic Strength Formation of DOPA‐Melanin Coating for Loading and Release of Cationic Antimicrobial Compounds

“…[32] The CDM particle appeared to play a crucial role in DOPA oxidation and epitaxial deposition of the DM shell, and it is therefore unclear if the method could provide a general approach to DM thin film formation on other substrates. A few reports showed the in-situ formation of thin DOPA-melanin (DM) coatings on polymeric membranes to improve wettability [33,34] and to act as a primer for covalent immobilization of molecules, [35–37] however in-situ grown DM films have only been shown to achieve thicknesses of 10 nm or less under conditions that typically yield much thicker films using dopamine. Thus, compared to PDA, the literature demonstrates that DM films are considerably more difficult to grow on substrates by spontaneous autoxidation of DOPA.…”

Biocatalysis with Unnatural Amino Acids: Enzymology Meets Xenobiology

“…Forexample,Deepankumar et al [111] were able to immobilize w-TAt ransaminase on chitosan and polystyrene beads after incorporation of as ingle DOPAr esidue by SCS.T he attachment proceeded through affinity adsorption, as DOPA-rich proteins are known to exhibit good affinities to inorganic surfaces as ac onsequence of the coordination of catechol units to metal ions,metal oxides,b orates,and silicates. [128] Af urther development of the method implies the use of ncAAs with bioorthogonal reactive side chains.T his is avery powerful tool in protein engineering [14f, 129] because it enables specific bioconjugation reactions through click chemistry,that is,c opper(I)-catalyzed azide-alkyne Huisgen cylcoaddition (CuAAC). [130] CuAACh as all the necessary features of an ideal click reaction:i ti ss pecific, rapid, and compatible with an aqueous environment, while offering high product yields without appreciable side products in as imple set-up.…”