Two different types of nonthrombogenic surfaces: PEG suppresses platelet adhesion ATP-independently but HEMA-St block copolymer requires ATP consumption of platelets to prevent adhesion.
Poly(ethylene glycol) (PEG) and a hydrophobic-hydrophilic microdomain structured block copolymer comprising poly(2-hydroxyethyl methacrylate) and polystyrene (HEMA-St) have been reported to show good blood compatibility owing to inhibition of platelet activation. By using a computer-assisted novel technique to analyze platelet behavior on the surfaces, we found two different mechanisms to prevent platelet adhesion. Platelets were prevented from adhesion and spreading on the microdomain surface and retained cell movement for a long time. The platelet movement velocity was not significantly different between PEG-grafted surfaces and HEMA-St block copolymer-cast surfaces. However, platelet motion was qualitatively different. Platelets on HEMA-St block copolymer-cast surfaces moved with rolling, spinning, and vibrating, whereas platelet movement was limited to oscillatory vibration on PEG-grafted surfaces. When platelets were treated with NaN(3), an adenosine triphosphate (ATP) synthesis inhibitor, before contacting the surfaces, platelets movement velocity was decreased only on HEMA-St block copolymer-cast surfaces. Such an inhibitory effect was hardly observed with platelets on PEG-grafted surfaces. We propose two different mechanisms to prevent platelet adhesion onto surfaces. One is ATP-independent as observed with PEG, and the other is ATP-dependent for HEMA-St block copolymer, where platelets consume ATP to prevent adhesion.
Uchida
K
K
Department of Applied Chemistry, Faculty of Science and Technology, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
Yamato
M
M
Ito
E
E
Kwon
O H
OH
Kikuchi
A
A
Sakai
K
K
Okano
T
T
D000255:Adenosine Triphosphate / Q000097:blood* / Q000494:pharmacology*; D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D002465:Cell Movement / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008855:Microscopy, Electron, Scanning; D010973:Platelet Adhesiveness / Q000187:drug effects*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011137:Polystyrenes / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D019810:Sodium Azide / Q000494:pharmacology
D001672:Biocompatible Materials; D011137:Polystyrenes; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate; D019810:Sodium Azide