Nuclear magnetic relaxation dispersion profile measured for

@ US-tubes in a 1% sodium dodecylbenzene sulfonate solution (c
Gd = 0.044 mM; T = 37°C) (◆). For comparative purposes, data for the commercially available CA, Magnevist™ or (Gd[DTPA])
2− (▲), are also shown. Inset: Depiction of a single US-tube loaded with hydrated Gd
3+ ions through sidewall defects created by cutting full-length nanotubes to produce US-tubes (not to scale and Cl
− anions and atoms attached to dangling C bonds not shown).