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Nerve growth factor‐immobilized polypyrrole: Bioactive electrically conducting polymer for enhanced neurite extension
Author(s) -
Gomez Natalia,
Schmidt Christine E.
Publication year - 2007
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.31047
Subject(s) - neurite , polypyrrole , materials science , nerve growth factor , conductive polymer , polymer , surface modification , stimulation , biophysics , biomedical engineering , nanotechnology , chemical engineering , polymer chemistry , polymerization , chemistry , composite material , biochemistry , in vitro , neuroscience , biology , receptor , medicine , engineering
Biomaterials that present multiple stimuli are attractive for a number of biomedical applications. In particular, electrical and biological cues are important factors to include in interfaces with neurons for applications such as nerve conduits and neural probes. Here, we report the combination of these two stimuli, by immobilizing nerve growth factor (NGF) on the surface of the electrically conducting polymer polypyrrole (PPy). NGF was immobilized using an intermediate linker provided by a layer of polyallylamine conjugated to an arylazido functional group. Upon exposure to UV light and activation of the azido groups, NGF was fixed to the substrate. Three different surface concentrations were obtained (0.21–0.98 ng/mm 2 ) and similar levels of neurite extension were observed on immobilized NGF as with soluble NGF. Additionally, electrical stimulation experiments were conducted with the modified polymer and revealed a 50% increase in neurite outgrowth in PC12 cells compared to experiments without electrical stimulation. This novel modification of PPy provides both electrical and biological stimulation, by presenting tethered growth factors and only producing a small decrease in the material's properties (conductivity ∼10 S cm −1 ) when compared to other modification techniques (conductivity ∼10 −3 –10 −6 S cm −1 ). © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007