DYNAMIC LIGHT SCATTERING AND RELAXOMETRIC STUDIES OF WATER-SOLUBLE Gd@C_+(60) DERIVATIVES AS pH-RESPONSIVE MRI CONTRAST AGENTS

摘要

Derivatized Gd@C2n-based nanomaterials are a promising new class of MRI contrast agent, and recent developments can now provide up to gram quantities of Gd@Cgo materials for study and evaluation, GdOQo-based MRI contrast agents potentially offer enhanced safety due to the endohedrally-sequestered metal ion. In this paper, two water-soluble Gd@C60 fullerenes, Gd@C6o[C(COOH)2]io and Gd@C6o(OH)x, have been evaluated as pH-responsive contrast agents in vitro. The T, relaxivity (Rfi for Gd@Cso[C(COOH)2]|0 increased by 300% between pH = 10 -* 4, while Gd@C6o(OH)x increased by 220%. This phenomenon has been interpreted to arise from slowly tumbling aggregates of the gadofullerenes that increase in size as the pH is lowered.