Method for increasing dispersion stability of nanoparticles as T1 MRI contrast agent and T1 MRI contrast nanoparticles

A method of preparing a druggable T1 contrast agent, the method comprising:

• (a) cross-linking dextran using epichlorohydrin and an amine cross-linking agent to provide a support particle, comprising hydrophilic chemical functional groups exposed on its surface, wherein
• (i) the hydrophilic chemical functional groups comprise amine groups;
• and
• (ii) the hydrodynamic size of the support particle is from 1-8 nm;
• (b) coordinating a T1 contrast material comprising Fe2+, Fe3+, or combination thereof on 20% or fewer of hydrophilic functional groups on the surface of the support particle to provide a particlized T1 contrast agent, wherein the hydrodynamic size of the particlized contrast agent is 2-6 nm;
• and
• (c) substituting the amine groups with carboxyl groups to provide the druggable T1 contrast agent;
• wherein the druggable T1 contrast agent of step (c) has reduced toxicity when intravenously administered relative to the particlized T1 contrast agent of step (b).