Hot off the press: accepted manuscript

Enhanced stability of superparamagnetic iron oxide nanoparticles in biological media using a pH adjusted-BSA adsorption protocol
Si-Ming Yu • Anna Laromaine* • Anna Roig*
J Nanopart Res (2014) 16:2484, DOI 10.1007/s11051-014-2484-1

SPIONs were  synthesized by  a facile, rapid  and cost  effective  microwave  assisted  method. Then,  a modified pH  adjusted-BSA  adsorption  protocol and an  addition of excess  trisodium citrate dihydrate (Na₃Cit) were used to enhance their stability in the media. The BSA adsorption protocol showed great efficiency in stabilizing the dispersed state of both SPIONs in the tested media, while the addition of excess Na₃Cit showed limit effect. The formed BSA layer on SPIONs could be imaged by negative staining TEM, and revealed by Cryo-TEM, FTIR, DLS and the zeta potential measurements. Results indicated that BSA forms a monolayer of a thickness of about 3 ± 1 nm and BSA interacts with SPIONs coating rather than by replacing them and interacting directly with the SPIONs surface. This synthetic method and stabilization protocol offer a general methodology to obtain SPIONs with a variety of surfactants, stable in different biological media in few minutes.