Patent ID: 8409463

Claim:
An aqueous method of making polymer coated superparamagnetic nanoparticles, the method comprising: (a) providing a mixture of iron salts in aqueous hydrochloric acid; (b) combining a solution of ammonium hydroxide with the mixture of (a) and stirring for a time sufficient for formation of a suspension of iron oxide nanoparticles; (c) adding to the suspension of (b) one or more aqueous biocompatible polymers, thereby coating the nanoparticles with polymer in the presence of unreacted reagents specified in (a) and (b); (d) centrifuging the suspension, rendering a supernatant without large particles; (e) filtering the supernatant through an ultrafiltration membrane and collecting the filtrate containing the polymer coated nanoparticles; (f) crosslinking the polymer coating by treating the nanoparticles with epichlorohydrin and sodium hydroxide while mixing; (g) aminating any un-aminated crosslinked polymer remaining by treating with ammonia; and (h) removing free epichlororohydrin from the suspension.