title: Temperature-dependent modulation of blood platelet movement and morphology on poly(N-isopropylacrylamide)-grafted surfaces.
abstract: Poly(N-isopropylacrylamide) (PIPAAm) exhibits a reversible, temperature-dependent soluble/insoluble transition at its lower critical solution temperature (LCST) of 32 degrees C in aqueous media. The temperature-responsive PIPAAm was grafted onto tissue culture polystyrene (TCPS) dish surfaces by electron beam irradiation. Blood platelet behaviors on PIPAAm-grafted surface were examined by computerized image analysis and scanning electron microscopy. Platelet behaviors on this surface were dramatically dependent upon temperature, but those on poly(ethylene glycol)(PEG)-grafted or polystyrene remained unchanged. Below the 32 degrees C (LCST), platelets on PIPAAm-grafted surfaces retained a rounded shape and an oscillating vibratory microbrownian motion for extended times, similarly to those on PEG-grafted surfaces. Above the LCST, platelets readily adhered, spread and developed characteristic pseudopodia on PIPAAm-grafted surface similarly to those on TCPS. An ATP synthesis inhibitor failed to hinder prevention of platelet adhesion onto PIPAAm-grafted surface (below the LCST) suggesting that the preventive mechanism is ATP-independent similarly to that of PEG-grafted surfaces. These results correlate platelet surface activation state with the hydration and structure of polymer surfaces, and demonstrate the ability to modulate such reactions by a small temperature change in situ.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Technology, Waseda University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Uchida
authors.forename: K
authors.initials: K
authors.lastname: Sakai
authors.forename: E
authors.initials: E
authors.lastname: Ito
authors.forename: O H
authors.initials: OH
authors.lastname: Kwon
authors.forename: A
authors.initials: A
authors.lastname: Kikuchi
authors.forename: M
authors.initials: M
authors.lastname: Yamato
authors.forename: T
authors.initials: T
authors.lastname: Okano
mesh_terms: D000178:Acrylamides; D001672:Biocompatible Materials; D001792:Blood Platelets / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D002448:Cell Adhesion; D002465:Cell Movement; D008855:Microscopy, Electron, Scanning; D009584:Nitrogen / Q000494:pharmacology; D011108:Polymers; D013696:Temperature
chemical_list: D000178:Acrylamides; D001672:Biocompatible Materials; D011108:Polymers; C003320:sodium nitride; C067295:N-isopropylacrylamide; D009584:Nitrogen