Temperature Dependence of Mucin Adsorption

Yakubov, Gleb E.; Ramsden, Jeremy J.

doi:10.1021/la702550f

Cited by 12 publications

(7 citation statements)

References 20 publications

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“…The refractive index increment  at 633 nm in pure water at 25 •C was determined using a Rudolph J357 refractometer as 0.140 ± 0.002 cm 3 /g, in agreement with previous results [31]. Teavigo (97% pure EGCG) was purchased from DSM (Switzerland) and stored under nitrogen.…”

Section: Mucin and Egcgsupporting

confidence: 86%

“…The available area function, , depends not only on M but also on the area a occupied by each adsorbing entity. Previous investigations showed that the adsorption kinetics of pure mucin (i.e., in the absence of EGCG) were consistent with random sequential adsorption (RSA) [31] and the EGCG-mucin complexes do not appear to be qualitatively different in this regard. The form of  appropriate to RSA of disks and spheres was used (equation 42 in ref.…”

Section: Corroboration Of the Adsorption Mechanismmentioning

confidence: 81%

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Surface rearrangement of adsorbed EGCG–mucin complexes on hydrophilic surfaces

Horváth

Yakubov

Ramsden

2017

International Journal of Biological Macromolecules

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The kinetic adsorption-desorption behaviour of porcine gastric mucin in the presence of physiologically relevant concentrations of the polyphenol epigallocatechin gallate (EGCG) was investigated using high-resolution kinetic optical waveguide lightmode spectroscopy (OWLS) and atomic force microscopy (AFM). Comparison with dynamic light scattering results from EGCGmucin mixtures indicates that discrete particles are formed whose size increases with increasing EGCG:mucin ratio. These particles are deduced to be the adsorbing entities, which fuse on the surface to form complex surface layers. At low molar EGCG:mucin ratios (< 1000), aggregates fuse on the surface to form a monolayer similar to one of pure mucin. With increasing EGCG concentration, the surface assembly of aggregates becomes consistent with their rearrangement and spreading in the shape of a spherical segment. At the highest molar ratios investigated (> 12 000) the particles begin to destabilize. The presence of EGCG leads to birefringence hysteresis during adsorption-desorption, indicating structural rearrangement, even at molar ratios 1000. The intensification of the phenomenon with increasing EGCG:mucin ratio mimics what was previously observed with the increase of mucin concentration in an EGCG-free system.

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Section: Mucin and Egcgsupporting

confidence: 86%

Section: Corroboration Of the Adsorption Mechanismmentioning

confidence: 81%

Surface rearrangement of adsorbed EGCG–mucin complexes on hydrophilic surfaces

Horváth

Yakubov

Ramsden

2017

International Journal of Biological Macromolecules

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“…The maximum adsorbed amounts ( M max ) are given in Table , which shows that the saturated adsorbed mass increases with concentration. Previously, it was found that Orthana mucin adsorption results in a composite bilayer structure, consisting of an uppermost layer that desorbs rapidly and a layer adjacent to the substrate that desorbs much slower − suggesting that the bilayer structure starts to form at 0.1 mg/mL, and up to 10 mg/mL the faster desorbing uppermost layer is small whereas above 20−30 mg/mL this layer becomes relatively thick. Analysis of the TE and TM modes of the optical waveguide enables the extraction of both the film thickness of the adsorbed mucin layer and the total adsorbed mass and it is found that film thickness increases with concentration .…”

Section: Resultsmentioning

confidence: 99%

“…The analysis of mucin desorption has been found to follow a double stretched exponential (Kohlrausch) kinetic law: M ( t ) = M max false[ f 1 e −( k 1 t ) normalβ 1 + false( 1 − f 1 false) e −( k 2 t ) normalβ 2 false] where M max is the amount of mucin adsorbed at the beginning of desorption, and f 1 , k i , and β i are constants. , Equation was fitted to the data and the fitted parameters for some representative adsorption−desorption curves are given in the Supporting Information. As previously, , the second stretched exponential dominates and we infer a composite structure of the adsorbed mucin layer, with a tightly bound equilibrium layer adjacent to the surface that desorbs slowly; superimposed on this is a structurally distinct second layer with faster rates of desorption. The characteristic desorption times for the slow and fast processes (Table ) are given by false⟨ τ i false⟩ = Γ false( / β i 1 false) / false( β i k i ...…”

Section: Resultsmentioning

confidence: 99%

Viscous Boundary Lubrication of Hydrophobic Surfaces by Mucin

et al. 2009

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The lubricating behavior of the weakly charged short-side-chain glycoprotein mucin "Orthana" (Mw=0.55 MDa) has been investigated between hydrophobic and hydrophilic PDMS substrates using soft-contact tribometry. It was found that mucin facilitates lubrication between hydrophobic PDMS surfaces, leading to a 10-fold reduction in boundary friction coefficient for rough surfaces. The presence of mucin also results in a shift of the mixed lubrication regime to lower entrainment speeds. The observed boundary lubrication behavior of mucin was found to depend on the bulk concentration, and we linked this to the structure and dynamics of the adsorbed mucin films, which are assessed using optical waveguide light spectroscopy. We observe a composite structure of the adsorbed mucin layer, with its internal structure governed by entanglement. The film thickness of this adsorbed layer increases with concentration, while the boundary friction coefficient for rough surfaces was found to be inversely proportional to the thickness of the adsorbed film. This link between lubrication and structure of the film is consistent with a viscous boundary lubrication mechanism, i.e., a thicker adsorbed film, at a given sliding speed, results in a lower local shear rate and, hence, in a lower local shear stress. The estimated local viscosities of the adsorbed layer, derived from the friction measurements and the polymer layer density, are in agreement with each other.

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“…[8][9][10][11][12][13] Considerable attention has been given to understanding the adsorption behavior of mucin and its important functional properties. [14][15][16][17] However, the molecular structure of mucin layers adsorbed onto polymer surfaces has not been sufficiently explored thus far. Little is also known about the conformational changes of mucin that might occur, as is the case for proteins, upon adsorption onto various polymer surfaces.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Ellipsometry of Mucin Layers on an Amphiphilic Diblock Copolymer Surface

Nikonenko

Bushnak²,

Keddie³

2009

Appl Spectrosc

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10 11Both visible and infrared (IR) spectroscopic ellipsometry have been employed to study the 12 structure of thin layers of bovine submaxillary mucin (BSM) adsorbed on poly(acrylic acid-13 block-methyl methacrylate) (PAA-b-PMMA) copolymer and poly(methyl methacrylate) 14 surfaces at three pH values (3, 7 and 10). The adsorbed mucin layer on the copolymer surface 15 had the greatest thickness (17 nm) when adsorbed from a mucin solution at a pH of 3. For the 16 first time, IR ellipsometry was used to identify adhesive interactions and conformational 17 changes in mucin/polymer double layers. After applying the regularized method of 18 deconvolution in the analysis, the formation of hydrogen bonds between the carboxyl groups of 19 the BSM and PAA-b-PMMA copolymer in double layers has been found. The IR ellipsometry 20 data, in agreement with the visible ellipsometry analysis, indicate the pH dependence of 21 adhesion of mucin to the copolymer surface. There is an increase in the amount of hydrogen-22 bonded carboxyl groups in mucin deposited at a pH of 3. There is no evidence that the mucin's 23 amide groups participate in this bonding. At the lower pH, the IR ellipsometry spectra after 24 deconvolution reveal an increase in the proportion of β-sheets in the BSM upon adsorption on 25 the copolymer surface, indicating a more unfolded, aggregated structure. The IR ellipsometry 26 data also indicated some changes in the conformational states of the side groups in the 27 copolymer induced by entanglements and bonding interactions with the mucin 28 macromolecules. Deconvolution provides an unprecedented level of information from the IR 29 ellipsometry spectra and yields important insights. 30 31

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Temperature Dependence of Mucin Adsorption

Cited by 12 publications

References 20 publications

Surface rearrangement of adsorbed EGCG–mucin complexes on hydrophilic surfaces

Surface rearrangement of adsorbed EGCG–mucin complexes on hydrophilic surfaces

Viscous Boundary Lubrication of Hydrophobic Surfaces by Mucin

Spectroscopic Ellipsometry of Mucin Layers on an Amphiphilic Diblock Copolymer Surface

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