title: Hyaluronan conformations on surfaces: effect of surface charge and hydrophobicity.
abstract: Extended, relaxed, condensed, and interacting forms of the polysaccharide hyaluronan have been observed by atomic force microscopy (AFM). The types of images obtained depend on the properties of the surfaces used. We have investigated several different surface conditions for HA imaging, including unmodified mica, mica chemically modified with two different kinds of amino-terminated silanes (3-aminopropyltriethoxysilane and N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride), and highly oriented pyrolytic graphite. We found the degree of HA molecular extension or condensation to be variable, and the number of bound chains per unit area was low, for all of the mica-based surfaces. HA was more easily imaged on graphite, a hydrophobic surface. Chains were frequently observed in high degrees of extension, maintained by favorable interaction with the surface after molecular combing. This observation suggests that the HA macromolecule interacts with graphite through hydrophobic patches along its surface. AFM studies of HA behavior on differing surfaces under well-controlled environmental conditions provides useful insight into the variety of conformations and interactions likely to be found under differing physiological conditions.
authors.affiliation: Othmer Department of Chemical and Biological Sciences and Engineering, Polytechnic University, 6 Metrotech Center, Brooklyn, NY 11201, USA.
authors.forename: Chiara
authors.initials: C
authors.lastname: Spagnoli
authors.forename: Alexander
authors.initials: A
authors.lastname: Korniakov
authors.forename: Abraham
authors.initials: A
authors.lastname: Ulman
authors.forename: Endre A
authors.initials: EA
authors.lastname: Balazs
authors.forename: Yuri L
authors.initials: YL
authors.lastname: Lyubchenko
authors.forename: Mary K
authors.initials: MK
authors.lastname: Cowman
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D002236:Carbohydrate Conformation; D006108:Graphite / Q000737:chemistry; D006820:Hyaluronic Acid / Q000737:chemistry* / Q000648:ultrastructure*; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D011437:Propylamines; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D011437:Propylamines; D000644:Quaternary Ammonium Compounds; D012821:Silanes; C050204:trimethyl-(3-(trimethoxysilyl)propyl)ammonium; D006108:Graphite; D006820:Hyaluronic Acid; C477625:amino-propyl-triethoxysilane; C011934:mica