title: A silver nanocomposite biomaterial for blood-contacting implants.
abstract: Cardiovascular implants must resist infection and thrombosis. A nanocomposite polymeric material [polyhedral-oligomeric-silsesquioxane-poly(carbonate-urea)urethane; POSS-PCU] demonstrates ideal properties for cardiovascular applications. Silver nanoparticles or nanosilver (NS) are recognized for efficient antibacterial properties. This study aims to determine the influence of NS integrated POSS-PCU on thrombogenicity. Silver nitrate was reduced with dimethylformamide and stabilized by the inclusion of fumed silica nanoparticles to prevent aggregation of NS and were incorporated into POSS-PCU to form a range of POSS-PCU-NS concentrations (by weight); 0.20% (NS16), 0.40% (NS32), 0.75% (NS64), and 1.50% (NS128). Surface wettability was determined with sessile-drop water contact angles. Platelets were introduced onto test samples and Alamar Blue (AB), mitochondrial-activity assay, quantified the degree of platelet adhesion whilst platelet-factor-4 (PF4) ELISA quantified the degree of platelet activation. Thromboelastography (TEG) determined the profiles of whole blood kinetics while hemolysis assay demonstrated the degree of blood compatibility. Increasing levels of NS induced greater hydrophilicity. A concentration dependant decrease in platelet adhesion and activation was observed with AB and PF4 readings, respectively. TEG demonstrated that the antithrombogenic properties of POSS-PCU were retained with POSS-PCU-NS16, and enhanced with POSS-PCU-NS32, but was reduced with POSS-PCU-NS64 and POSS-PCU-NS128. POSS-PCU-NS64 and POSS-PCU-NS128 demonstrated a hemolytic tendency, but no hemolysis was observed with POSS-PCU-NS16 and POSS-PCU-NS32. Overall, POSS-PCU-NS32 rendered potent antithrombogenic properties.
authors.affiliation: UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London, London, United Kingdom.
authors.forename: Achala
authors.initials: A
authors.lastname: de Mel
authors.forename: Karla
authors.initials: K
authors.lastname: Chaloupka
authors.forename: Yogeshkumar
authors.initials: Y
authors.lastname: Malam
authors.forename: Arnold
authors.initials: A
authors.lastname: Darbyshire
authors.forename: Brian
authors.initials: B
authors.lastname: Cousins
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Seifalian
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D001792:Blood Platelets / Q000166:cytology; D006461:Hemolysis; D006801:Humans; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D017646:Organosilicon Compounds / Q000737:chemistry / Q000378:metabolism*; D015539:Platelet Activation; D010973:Platelet Adhesiveness; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000378:metabolism; D011140:Polyurethanes / Q000737:chemistry / Q000378:metabolism*; D012834:Silver / Q000737:chemistry / Q000378:metabolism*; D013916:Thrombelastography; D017155:Wettability
chemical_list: D001672:Biocompatible Materials; D017646:Organosilicon Compounds; D010975:Platelet Aggregation Inhibitors; D011140:Polyurethanes; C110029:poly(carbonate urea) urethane; C521417:polyhedraloligosilsesquioxane; D012834:Silver