title: Imparting electroactivity to polycaprolactone fibers with heparin-doped polypyrrole: Modulation of hemocompatibility and inflammatory responses.
abstract: Hemocompatibility, anti-inflammation and anti-thrombogenicity of acellular synthetic vascular grafts remains a challenge in biomaterials design. Using electrospun polycaprolactone (PCL) fibers as a template, a coating of polypyrrole (PPy) was successfully polymerized onto the fiber surface. The fibers coated with heparin-doped PPy (PPy-HEP) demonstrated better electroactivity, lower surface resistivity (9-10-fold) and better anti-coagulation response (non-observable plasma recalcification after 30min vs. recalcification at 8-9min) as compared to fibers coated with pristine PPy. Red blood cell compatibility, measured by% hemolysis, was greatly improved on PPy-HEP-coated PCL in comparison to uncoated PCL (3.9±2.1% vs. 22.1±4.1%). PPy-HEP-coated PCL fibers also exhibited higher stiffness values (6.8±0.9MPa vs. 4.2±0.8MPa) as compared to PCL fibers, but similar tensile strengths. It was also observed that the application of a low alternating current led to a 4-fold reduction of platelet activation (as quantitated by CD62p expression) for the PPy-HEP-coated fibers as compared to non-stimulated conditions. In parallel, a reduction in the leukocyte adhesion to both pristine PPy-coated and PPy-HEP-coated fibers was observable with AC stimulation. Overall, a new strategy involving the use of hemocompatible conducting polymers and electrical stimulation to control thrombogenicity and inflammatory responses for synthetic vascular graft designs was demonstrated.
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Gordon M
authors.initials: GM
authors.lastname: Xiong
authors.affiliation: Multi-phase Mass Transfer and Reaction Engineering Laboratory, College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Shaojun
authors.initials: S
authors.lastname: Yuan
authors.affiliation: Residues and Resource Reclamation Centre (R3C), Nanyang Environmental and Water Research Institute (NEWRI), 1 Cleantech Loop, Singapore 637141, Singapore; Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Jun Kit
authors.initials: JK
authors.lastname: Wang
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University, Block S2.1, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Anh Tuan
authors.initials: AT
authors.lastname: Do
authors.affiliation: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
authors.forename: Nguan Soon
authors.initials: NS
authors.lastname: Tan
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University, Block S2.1, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Kiat Seng
authors.initials: KS
authors.lastname: Yeo
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798, Singapore. Electronic address: cleochoong@ntu.edu.sg.
authors.forename: Cleo
authors.initials: C
authors.lastname: Choong
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000633:toxicity; D002478:Cells, Cultured; D004343:Drug Implants / Q000008:administration & dosage* / Q000737:chemistry; D004553:Electric Conductivity; D004599:Electric Stimulation Therapy / Q000379:methods*; D006461:Hemolysis / Q000187:drug effects; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D008422:Materials Testing; D057139:Nanofibers / Q000737:chemistry* / Q000633:toxicity; D015539:Platelet Activation / Q000187:drug effects / Q000528:radiation effects; D011091:Polyesters / Q000737:chemistry* / Q000633:toxicity; D011108:Polymers / Q000737:chemistry* / Q000633:toxicity; D011758:Pyrroles / Q000737:chemistry* / Q000633:toxicity
chemical_list: D001672:Biocompatible Materials; D004343:Drug Implants; D011091:Polyesters; D011108:Polymers; D011758:Pyrroles; C016240:polycaprolactone; C067635:polypyrrole; D006493:Heparin
keywords: Electrical stimulation; Heparin; Polycaprolactone; Polypyrrole; Vascular grafts