title: Biofunctionalization of PEDOT films with laminin-derived peptides.
abstract: Poly(3,4-ethylenedioxythiophenes) (PEDOT) have been extensively explored as materials for biomedical implants such as biosensors, tissue engineering scaffolds and microelectronic devices. Considerable effort has been made to incorporate biologically active molecules into the conducting polymer films in order to improve their long term performance at the soft tissue interface of devices, and the development of functionalized conducting polymers that can be modified with biomolecules would offer important options for device improvement. Here we report surface modification, via straightforward protocols, of carboxylic-acid-functional PEDOT copolymer films with the nonapeptide, CDPGYIGSR, derived from the basement membrane protein laminin. Evaluation of the modified surfaces via XPS and toluidine blue O assay confirmed the presence of the peptide on the surface and electrochemical analysis demonstrated unaltered properties of the peptide-modified films. The efficacy of the peptide, along with the impact of a spacer molecule, for cell adhesion and differentiation was tested in cell culture assays employing the rat pheochromocytoma (PC12) cell line. Peptide-modified films comprising the longest poly(ethylene glycol) (PEG) spacer used in this study, a PEG with ten ethylene glycol repeats, demonstrated the best attachment and neurite outgrowth compared to films with peptides alone or those with a PEG spacer comprising three ethylene glycol units. The films with PEG10-CDPGYISGR covalently modified to the surface demonstrated 11.5% neurite expression with a mean neurite length of 90μm. This peptide immobilization technique provides an effective approach to biofunctionalize conducting polymer films.
  
  
  
  For enhanced diagnosis and treatment, electronic devices that interface with living tissue with minimum shortcomings are critical. Towards these ends, conducting polymers have proven to be excellent materials for electrode-tissue interface for a variety of biomedical devices ranging from deep brain stimulators, cochlear implants, and microfabricated cortical electrodes. To improve the electrode-tissue interface, one strategy utilized by many researchers is incorporating relevant biological molecules within or on the conducting polymer thin films to provide a surface for cell attachment and/or provide biological cues for cell growth. The present study provides a facile means for generating PEDOT films grafted with a laminin peptide with or without a spacer molecule for enhanced cell attachment and neurite extension.
authors.affiliation: Department of Materials Science and Engineering, University of Delaware, 19716, USA.
authors.forename: Nandita
authors.initials: N
authors.lastname: Bhagwat
authors.affiliation: Department of Physics and Astronomy, University of Delaware, 19716, USA.
authors.forename: Roy E
authors.initials: RE
authors.lastname: Murray
authors.affiliation: Department of Materials Science and Engineering, University of Delaware, 19716, USA; Department of Physics and Astronomy, University of Delaware, 19716, USA.
authors.forename: S Ismat
authors.initials: SI
authors.lastname: Shah
authors.affiliation: Department of Materials Science and Engineering, University of Delaware, 19716, USA. Electronic address: kiick@udel.edu.
authors.forename: Kristi L
authors.initials: KL
authors.lastname: Kiick
authors.affiliation: Department of Materials Science and Engineering, University of Delaware, 19716, USA. Electronic address: milty@udel.edu.
authors.forename: David C
authors.initials: DC
authors.lastname: Martin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D002448:Cell Adhesion / Q000187:drug effects; D017097:Electric Impedance; D007797:Laminin / Q000737:chemistry / Q000494:pharmacology*; D016716:PC12 Cells; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D056951:Photoelectron Spectroscopy; D011108:Polymers / Q000737:chemistry*; D051381:Rats; D013499:Surface Properties; D014048:Tolonium Chloride / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007797:Laminin; D010455:Peptides; D011108:Polymers; C121383:poly(3,4-ethylene dioxythiophene); D014048:Tolonium Chloride
keywords: Biofunctionalization; Copolymer films; PEDOT; Surface characterfization; Surface modification