Method for continuous growth of water-soluble magnetic nanomaterials

A method of continuous synthesis of water-soluble metal oxide nanoparticles of varying sizes, the method comprising:

• a. performing a first heating operation on a reaction mixture at an initial temperature of about 100° C. to about 140° C. for an initial time duration of about 1 hour to about 3 hours, the reaction mixture comprising a first predetermined amount of a reactant and a polyol, wherein the polyol is diethylene glycol (DEG);
• b. performing a second heating operation, on the reaction mixture obtained from the first heating operation, at a predetermined temperature for a predetermined time duration to obtain water-soluble metal oxide nanoparticles of a selected first size, wherein the first predetermined amount of the reactant added during the first heating operation is determined by the selected first size, wherein the predetermined temperature is greater than the initial temperature;
• c. adding a second predetermined amount of the reactant to the reaction mixture obtained from the second heating operation;
• and
• d. performing a third heating operation, on the reaction mixture obtained from adding the second predetermined amount of the reactant, at the predetermined temperature for the predetermined time duration to obtain water-soluble metal oxide nanoparticles of a selected second size, wherein the second predetermined amount of the reactant added is determined by the selected second size,
• wherein the water-soluble metal oxide nanoparticles having a size of around 9 nm exhibit a transversal relaxivity of around 425 mMol-1.s-1 and a longitudinal relaxivity of around 32 mMol-1.s-1.

A method of synthesizing water-soluble metal oxide nanoparticles having incremental particle sizes, the method comprising:

• a. performing a preliminary heating operation on a reaction mixture at an initial temperature in a range of about 100° C. to about 140° C. for an initial time duration prior to performing any heating operation, wherein the initial temperature is less than a predetermined temperature;
• b. performing a heating operation on the reaction mixture at the predetermined temperature in a range of about 200° C. to about 240° C. for a predetermined time duration to obtain water-soluble metal oxide nanoparticles of a first size, the reaction mixture comprising a reactant and a polyol, wherein the polyol is diethylene glycol (DEG);
• and
• c. performing recursively an addition operation of a predetermined amount of the reactant to the reaction mixture obtained from a previous heating operation and a heating operation on the reaction mixture, obtained from the addition operation, at the predetermined temperature for the predetermined time duration to obtain water-soluble metal oxide nanoparticles,
• wherein the particle size of water-soluble metal oxide nanoparticles obtained from every heating operation is greater than the particle size of water-soluble metal oxide nanoparticles obtained from a previous heating operation and wherein the water-soluble metal oxide nanoparticles having a size of around 9 nm exhibit a transversal relaxivity of around 425 mMol-1.s-1 and a longitudinal relaxivity of around 32 mMol-1.s-1.