title: A biodegradable electrical bioconductor made of polypyrrole nanoparticle/poly(D,L-lactide) composite: A preliminary in vitro biostability study.
abstract: The electrical stability of a novel polypyrrole (PPy)/poly(D,L-lactide) (PDLLA) composite was studied in vitro and compared with that of PPy-coated polyester fabrics. Specimens were incubated in Ringer's solution at 37 degrees C for up to 8 weeks with or without the circulation of DC current under a constant 100 mV voltage. In situ current variation with incubation time was recorded. The AC volume electrical conductivity of the specimens before and after incubation in phosphate-buffered saline was recorded using a frequency analyzer. Water absorption and weight loss were monitored metrologically. Changes in the oxidation state of incubated PPy were analyzed with X-ray photoelectron spectroscopy. The morphological changes were observed with scanning electron microscopy, and the glass transition temperature of the PDLLA was investigated using differential scanning calorimetry. The PPy/PDLLA composite in Ringer's solution sustained a relatively stable conductivity up to 8 weeks after an initial period of "conditioning." The PPy-coated fabrics experienced a rapid loss of conductivity when subjected to electrical circulation and regained part of it when disconnected. The volume conductivity of the nonincubated PPy/PDLLA membrane behaved as a typical conductor in the low-frequency range. The mechanisms involved in the various electrical behaviours of the PPy/PDLLA composite and PPy-coated fabrics are discussed. In conclusion, the PPy/PDLLA composite was able to deliver a biologically significant electrical current in a simulated biological solution for up to 8 weeks and therefore may be considered as a first-generation synthetic biodegradable bioconductor.
authors.affiliation: Département de Chirurgie, Université Laval, Institut biomatériaux de Québec, Pavillon Saint-François d'Assise, Québec, Canada. Ze.Zhang@chg.ulaval.ca
authors.forename: Zhaoxu
authors.initials: Z
authors.lastname: Wang
authors.forename: Christophe
authors.initials: C
authors.lastname: Roberge
authors.forename: Ying
authors.initials: Y
authors.lastname: Wan
authors.forename: Lê H
authors.initials: LH
authors.lastname: Dao
authors.forename: Robert
authors.initials: R
authors.lastname: Guidoin
authors.forename: Ze
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D002152:Calorimetry, Differential Scanning; D004553:Electric Conductivity; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology; D010084:Oxidation-Reduction; D011091:Polyesters / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D014867:Water; C033616:poly(lactide)