Figure 2. NSC viability on PPy depended on the counter ion incorporated in the conducting polymer.

(A) Alternative methods used to obtain NSC cultures: fetal NSCs were derived from developing cerebral cortices from rats and kept in a proliferative state by the addition of FGF2, whereas ESC-NSC were derived from previously isolated ESCs from mice and kept multipotent in the presence of FGF2/EGF. ICM  =  inner cell mass. (B) Fetal NSCs and ESC-NSCs grown on PPy(DBS) for 2 days in N2 media supplemented with FGF2 or FGF2/EGF showed immunoreactivity for the NSC markers Nestin and BLBP, respectively. TsO, ClO₄ and Cl as counter ions in PPy compromised cell viability. (C) Quantification of the average number of live and dead cells in (B) as calculated from five random 10x images from three separate experiments. PPy(DBS) surfaces showed high NSC viability, whereas surfaces with the three smaller ions, TsO, ClO₄ and Cl, had none or few live cells. Fetal NSCs and ESC-NSCs were very similar in their response to the PPy doping ion. 1-Way ANOVA analysis of variance was used followed by Tukey's multiple comparison test. The scale bar represents 200 µm.