During fabrication carbon nanotubes (CNTs) will acquire hydrophilic ends (such as -OH, -COOH, -H) and, if desired, they can be further modified such that other functional groups are covalently attached to the partially charged termini. Moreover, the sidewalls of NTs can be modified either by covalently bonding functional groups or by wrapping a molecule around the surface. A recent review by Karousis et al outlines various approaches used to modify CNTs by covalently bonding functional groups on their external surface or otherwise.