title: Haemocompatibility improvement of metallic surfaces by covalent immobilization of heparin-liposomes.
abstract: Stainless steel surfaces were processed by means of plasma enhanced chemical vapor deposition (PE-CVD) fed with acrylic acid vapors in order to functionalize them with carboxyl groups, which were subsequently activated for covalent immobilization of heparin-loaded (HEP) NH(2) group-functionalized (Fun) nanoliposomes (NLs). Empty Fun or HEP non-functionalized (control) NLs were used as controls. NLs were characterized for mean diameter, surface charge and heparin encapsulation/release. Different lipid compositions were used for NL construction; PC/Chol (2:1mol/mol) or PC/Chol (4:1mol/mol) (fluid type vesicles) [which allow gradual release of heparin] and DSPC/Chol (2:1mol/mol) (rigid type vesicles). Surface haemocompatibility was tested by measuring blood clotting time. Platelet adhesion on surfaces was evaluated morphologically by SEM and CLSM. The haemocompatibility of plasma-processed surfaces was improved (compared to untreated surfaces); Fun-HEP NL-coated surfaces demonstrated highest coagulation times. For short surface/blood incubation periods, surfaces coated with Fun-HEP NLs consisting of PC/Chol (2:1) had higher coagulation times (compared to DSPC/Chol NLs) due to faster release of heparin. Heparin release rate from the various NL types and surface platelet adhesion results were in agreement with the corresponding blood coagulation times. Concluding, covalent immobilization of drug entrapping NLs on plasma processed surfaces is a potential method for preparation of controlled-rate drug-eluting metallic stents or devices.
authors.affiliation: Laboratory of Pharmaceutical Technology, Dept. of Pharmacy, School of Health Sciences, University of Patras, Rio 26510, Greece.
authors.forename: Michail
authors.initials: M
authors.lastname: Kastellorizios
authors.forename: Georgios P A K
authors.initials: GP
authors.lastname: Michanetzis
authors.forename: Bianca Rita
authors.initials: BR
authors.lastname: Pistillo
authors.forename: Spyridon
authors.initials: S
authors.lastname: Mourtas
authors.forename: Pavlos
authors.initials: P
authors.lastname: Klepetsanis
authors.forename: Piero
authors.initials: P
authors.lastname: Favia
authors.forename: Eloisa
authors.initials: E
authors.lastname: Sardella
authors.forename: Ricardo
authors.initials: R
authors.lastname: d'Agostino
authors.forename: Yannis F
authors.initials: YF
authors.lastname: Missirlis
authors.forename: Sophia G
authors.initials: SG
authors.lastname: Antimisiaris
mesh_terms: D000925:Anticoagulants / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry; D006493:Heparin / Q000737:chemistry*; D006801:Humans; D008081:Liposomes; D008670:Metals; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010949:Plasma / Q000737:chemistry; D010973:Platelet Adhesiveness; D011092:Polyethylene Glycols / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry*
chemical_list: C519184:1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy-poly(ethylene glycol 2000); D000925:Anticoagulants; D008081:Liposomes; D008670:Metals; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D013193:Stainless Steel; D011092:Polyethylene Glycols; D006493:Heparin; D002784:Cholesterol