TY - JOUR
T1 - Measurements of conformational changes during adhesion of lipid and protein (polylysine and S‐layer) surfaces
AU - Leckband, Deborah
AU - Chen, You‐Lung ‐L
AU - Israelachvili, Jacob
AU - Wickman, H. Hollis
AU - Fletcher, Madilyn
AU - Zimmerman, Robert
PY - 1993/6/20
Y1 - 1993/6/20
N2 - The adhesion forces between various surfaces were measured using the 'surface forces apparatus' technique. This technique allows for the thickness of surface layers and the adhesion force between them to be directly measured in controlled vapor or liquid environments. Three types of biological surfaces were prepared by depositing various lipid-protein monolayers (with thicknesses ranging from 1 to 4 nm) on the inert, molecularly smooth mica surface: (i) hydrophobic lipid monolayers; (ii) amphiphilic polyelectrolyte surfaces of adsorbed polylysine; and (iii) deposited bacterial S-layer proteins. The adhesion, swelling, and wetting properties of these surfaces was measured as a function of relative humidity and time. Initial adhesion is due mainly to the van der Waals forces arising from nonpolar (hydrophobic) contacts. Following adhesive contact, significant molecular rearrangements can occur which alter their hydrophobic- hydrophilic balance and increase their adhesion with time. Increased adhesion is generally enhanced by (i) increased relative humidity (or degree of hydration); (ii) increased contact time; and (iii) increased rates of separation. The results are likely to be applicable to the adhesion of many other biosurfaces, and show that the hydrophobicity of a lipid or protein surface is not an intrinsic property of that surface but depends on its environment (e.g., on whether it is in aqueous solution or exposed to the atmosphere), and on the relative humidity of the atmosphere. It also depends on whether the surface is in adhesive contact with another surface and -when considering dynamic (nonequilibrium) conditions-on the time and previous history of its interaction with that surface.
AB - The adhesion forces between various surfaces were measured using the 'surface forces apparatus' technique. This technique allows for the thickness of surface layers and the adhesion force between them to be directly measured in controlled vapor or liquid environments. Three types of biological surfaces were prepared by depositing various lipid-protein monolayers (with thicknesses ranging from 1 to 4 nm) on the inert, molecularly smooth mica surface: (i) hydrophobic lipid monolayers; (ii) amphiphilic polyelectrolyte surfaces of adsorbed polylysine; and (iii) deposited bacterial S-layer proteins. The adhesion, swelling, and wetting properties of these surfaces was measured as a function of relative humidity and time. Initial adhesion is due mainly to the van der Waals forces arising from nonpolar (hydrophobic) contacts. Following adhesive contact, significant molecular rearrangements can occur which alter their hydrophobic- hydrophilic balance and increase their adhesion with time. Increased adhesion is generally enhanced by (i) increased relative humidity (or degree of hydration); (ii) increased contact time; and (iii) increased rates of separation. The results are likely to be applicable to the adhesion of many other biosurfaces, and show that the hydrophobicity of a lipid or protein surface is not an intrinsic property of that surface but depends on its environment (e.g., on whether it is in aqueous solution or exposed to the atmosphere), and on the relative humidity of the atmosphere. It also depends on whether the surface is in adhesive contact with another surface and -when considering dynamic (nonequilibrium) conditions-on the time and previous history of its interaction with that surface.
KW - adhesion
KW - hydrophobic interactions
KW - protein adhesion
KW - protein hydration
KW - S-layers
KW - van der Waals forces
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U2 - 10.1002/bit.260420204
DO - 10.1002/bit.260420204
M3 - Article
C2 - 18612977
AN - SCOPUS:0027607294
SN - 0006-3592
VL - 42
SP - 167
EP - 177
JO - Biotechnology and Bioengineering
JF - Biotechnology and Bioengineering
IS - 2
ER -