Shear-Induced Adhesion in Mussel Foot Protein-1 Films

Frontiers in Mechanical Engineering, 2021

To attach to surfaces in the sea, sea stars produce proteinaceous adhesive secretions. Sfp1 is a major constituent of this adhesive, where it is present in the form of four subunits (named Sfp1α to δ) displaying specific protein-, carbohydrate- and metal-binding domains. Recently, two recombinant proteins inspired from Sfp1 have been produced: one corresponding to the C-terminal part of Sfp1β and the other to the full-length Sfp1δ. Adsorption ability tests showed that both recombinant proteins were able to adsorb and to form coatings on different surfaces in artificial seawater as well as in Tris buffer supplemented with NaCl or CaCl2. In this study, we used Atomic Force Microscopy (AFM) to characterize the nanomechanical properties of these coatings with an emphasis on functional characteristics such as adhesive properties and modulus of elasticity. We used AFM techniques which are the most appropriate to characterize the coating microstructure combined with the mapping of its nano...

Biophysical Journal, 1999

Using the manipulation force microscope, a novel atomic force microscope, the adhesion forces of bovine serum albumin, myoglobin, ferritin, and lysozyme proteins to glass and polystyrene substrates were characterized by following the force necessary to displace an adsorbed protein-covered microsphere over several orders of magnitude in time. This force was consistent with a power law with exponent a ϭ 0.37 Ϯ 0.03 on polystyrene, indicating that there is no typical time scale for adhesion on this substrate. On glass, the rate of adhesion depended strongly on protein charge. Forces corresponding to single protein adhesion events were identified. The typical rupture force of a single lysozyme, ferritin, bovine serum albumin, and myoglobin protein adhering to glass was estimated to be 90 Ϯ 10 pN, 115 Ϯ 13 pN, 277 Ϯ 44 pN, and 277 Ϯ 44 pN, respectively, using a model of the experimental system. These forces, as well as the force amplitudes on hydrophobic polystyrene, correlate with protein stiffness.

Advanced Functional Materials, 2010

Mussels use a variety of 3, 4-dihydroxyphenyl-L-alanine (DOPA) rich proteins specifically tailored to adhering to wet surfaces. Synthetic polypeptide analogues of adhesive mussel foot proteins (specifically mfp-3) are used to study the role of DOPA in adhesion. The mussel-inspired peptide is a random copolymer of DOPA and N 5-(2-hydroxyethyl)-L-glutamine synthesized with DOPA concentrations of 0-27 mol% and molecular weights of 5.9-7.1 kDa. Thin films (3-5 nm thick) of the mussel-inspired peptide are used in the surface forces apparatus (SFA) to measure the forcedistance profiles and adhesion and cohesion energies of the films in an acetate buffer. The adhesion energies of the mussel-inspired peptide films to mica and TiO 2 surfaces increase with DOPA concentration. The adhesion energy to mica is 0.09 μJ m −2 mol DOPA −1 and does not depend on contact time or load. The adhesion energy to TiO 2 is 0.29 μJ m −2 mol DOPA −1 for short contact times and increases to 0.51 μJ m −2 mol DOPA −1 for contact times >60 min in a way suggestive of a phase transition within the film. Oxidation of DOPA to the quinone form, either by addition of periodate or by increasing the pH, increases the thickness and reduces the cohesion of the films. Adding thiol containing polymers between the oxidized films recovers some of the cohesion strength. Comparison of the mussel-inspired peptide films to previous studies on mfp-3 thin films show that the strong adhesion and cohesion in mfp-3 films can be attributed to DOPA groups favorably oriented within or at the interface of these films.

Physical Review Letters, 2013

The mechanical force-induced activation of the adhesive protein von Willebrand Factor (VWF), which experiences high hydrodynamic forces, is essential in initiating platelet adhesion. The importance of the mechanical force-induced functional change is manifested in the multimeric VWF's crucial role in blood coagulation, when high fluid shear stress activates plasma VWF (pVWF) multimers to bind platelets. Here we showed that a pathological level of high shear stress exposure of pVWF multimers results in domain conformational changes, and the subsequent shifts in the unfolding force allow us to use force as a marker to track the dynamic states of multimeric VWF. We found that shear-activated pVWF multimers (spVWF) are more resistant to mechanical unfolding than non-sheared pVWF multimers, as indicated in the higher peak unfolding force. These results provide insight into the mechanism of shear-induced activation of pVWF multimers.

Langmuir, 2002

Langmuir, 2005

The adhesive properties of untreated and corona treated polypropylene (PP) films were studied in polar (water) and nonpolar (hexadecane) liquid medium by using chemical force microscopy. A gold-coated colloidal probe was sequentially modified with self-assembled monolayers (SAMs) of ω-functionalized alkanethiols. The same colloidal probe was used for the force measurements, to avoid influence of determination accuracy of the spring constant and sphere radius on the obtained results. The thermodynamic work of adhesion was determined from the measured pull-off force using the Johnson-Kendall-Roberts (JKR) adhesion theory. Rabinovich's model was applied for the consideration of an effect of roughness when calculating the work of adhesion. It was found that the work of adhesion correlates with the hydrophilic properties of the PP surface and SAMs as well as with the polarity of the liquid medium. The observed correlations agree well with those found for the work of adhesion calculated from contact angle measurement.

Journal of The American Chemical Society, 1995

Adhesion forces between well-ordered organomercaptan monolayer films strongly bound to both a Au substrate and a microscopic Au probe were measured over separations ranging from -10 nm to repulsive contact and probe radii from 50 nm to 60 p m using interfacial force microscopy. Films terminated with methyl groups (CH3 vs CH3) were examined and these results are contrasted with hydrogen-bonding (NH2 vs NH2 and COOH vs COOH) and acid-base (NH2 vs COOH) combinations. From the peak value of the adhesive pull-off force, we calculate interfacial bond energies using a model that has been shown to be applicable in such situations. These values qualitatively scale with those expected for van der Waals, hydrogen-bonding, and acid-base interactions. The force-versus-displacement behavior, which has not previously been measured, is suggested to be dominated by the distinctive mechanical properties of the films. Professor J. Mann and Dr. Alexis Grabbe for many useful and informative discussions. R.C.T. acknowledges the support of Associated Westem Universities through a Department of Energy laboratory graduate fellowship. T.K. and R.M.C.

Biomacromolecules, 2014

Model layer-by-layer (LbL) assemblies of poly-(allylamine hydrochloride) (PAH) and hyaluronic acid (HA) were fabricated in order to study their wet adhesive behavior. The film characteristics were investigated to understand the inherent structures during the assembly process. Subsequently, the adhesion of these systems was evaluated to understand the correlation between the structure of the film and the energy required to separate these LbL assemblies. We describe how the conditions of the LbL fabrication can be utilized to control the adhesion between films. The characteristics of the film formation are examined in the absence and presence of salt during the film formation. The dependence on contact time and LbL film thickness on the critical pull-off force and work of adhesion are discussed. Specifically, by introducing sodium chloride (NaCl) in the assembly process, the pull-off forces can be increased by a factor of 10 and the work of adhesion by 2 orders of magnitude. Adjusting both the contact time and the film thickness enables control of the adhesive properties within these limits. Based on these results, we discuss how the fabrication procedure can create tailored adhesive interfaces with properties surpassing analogous systems found in nature.

Proceedings of the National Academy of Sciences of the United States of America, 2016

Translating sticky biological molecules-such as mussel foot proteins (MFPs)-into synthetic, cost-effective underwater adhesives with adjustable nano- and macroscale characteristics requires an intimate understanding of the glue's molecular interactions. To help facilitate the next generation of aqueous adhesives, we performed a combination of surface forces apparatus (SFA) measurements and replica-exchange molecular dynamics (REMD) simulations on a synthetic, easy to prepare, Dopa-containing peptide (MFP-3s peptide), which adheres to organic surfaces just as effectively as its wild-type protein analog. Experiments and simulations both show significant differences in peptide adsorption on CH3-terminated (hydrophobic) and OH-terminated (hydrophilic) self-assembled monolayers (SAMs), where adsorption is strongest on hydrophobic SAMs because of orientationally specific interactions with Dopa. Additional umbrella-sampling simulations yield free-energy profiles that quantitatively agr...