title: Electroactivity and biocompatibility of polypyrrole-hyaluronic acid multi-walled carbon nanotube composite.
abstract: Electroactivity of polypyrrole hyaluronic acid, electropolymerized in the presence of oxidized carbon nanotubes (PPyHA-CNT) was studied in situ by electrochemical atomic force microscopy (EC-AFM) in physiological electrolyte solution. In situ Raman spectroscopic and quartz crystal microbalance (QCM) studies were conducted on layers of the polymer grown on AT-cut 5 MHz quartz crystals. Human adipose stem cell (ASC) attachment and viability were studied by Live/Dead staining, and the proliferation was evaluated by WST-1 Cell proliferation assay for polypyrrole samples electropolymerized on titanium. According to cyclic voltammetry, the measured specific capacitance of the material on gold is roughly 20% of the reference polypyrrole dodecylbenzene sulfonate (PPyDBS). Electrochemical-QCM (EC-QCM) analysis of a 210-nm thick film reveals that the material is very soft G' approximately 100 kPa and swells upon reduction. EC-AFM of samples polymerized on microelectrodes show that there are areas of varying electroactivity, especially for samples without a hydrophopic backing PPyDBS layer. AFM line scans show typically 20-25% thickness change during electrochemical reduction. Raman spectroscopic analysis suggests that the material supports noticeable polaron conduction. Biocompatibility study of the PPyHA-CNT on titanium with adipose stem cells showed equal or better cell attachment, viability, and proliferation compared with the reference polylactide.
authors.affiliation: VTT Technical Research Centre of Finland, Sinitaival 6, P.O. Box 1300, 33101 Tampere, Finland. jani.pelto@vtt.fi
authors.forename: Jani
authors.initials: J
authors.lastname: Pelto
authors.forename: Suvi
authors.initials: S
authors.lastname: Haimi
authors.forename: Esa
authors.initials: E
authors.lastname: Puukilainen
authors.forename: Philip G
authors.initials: PG
authors.lastname: Whitten
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Spinks
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Bahrami-Samani
authors.forename: Mikko
authors.initials: M
authors.lastname: Ritala
authors.forename: Tommi
authors.initials: T
authors.lastname: Vuorinen
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003460:Crystallization; D004563:Electrochemistry / Q000379:methods*; D006801:Humans; D006820:Hyaluronic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D008422:Materials Testing / Q000379:methods*; D018625:Microscopy, Atomic Force; D008875:Middle Aged; D010084:Oxidation-Reduction / Q000187:drug effects; D011758:Pyrroles / Q000737:chemistry / Q000494:pharmacology*; D011791:Quartz; D013059:Spectrum Analysis, Raman; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects
chemical_list: D001672:Biocompatible Materials; D011758:Pyrroles; D011791:Quartz; D006820:Hyaluronic Acid