Research Article
Effect of Functionalized Carbon Nanotubes and their Citric Acid Polymerization on Mesenchymal Stem Cells In Vitro
Figure 3
Infrared spectra of (a, c) acid-functionalized MWNTs and CNxs, respectively, showing the bands between 1750 and 2200 cm−1 related to the C-C bonds. The OH band obtained by functionalization is present at 2500 cm−1. For the polymerized CNTs (b, d), the broad band at 3600 cm−1 is related to the OH groups associated to PCA.