Combinatorial Discovery of Novel Amphiphilic Polymers for the Phase Transfer of Magnetic Nanoparticles

In this paper, we present a new approach to the combinatorial discovery of amphiphilic maleic anhydride copolymers which can be used as a generic method for the optimization and control of hydrophobic nanoparticle phase transfer into the aqueous phase. This combinatorial multiwell chemical screening process resulted in the discovery of 'hit' polymer ring opened chemistries that allow the spontaneous and highly efficient phase transfer of superparamagnetic iron oxide (SPIO) nanoparticles into water under ambient conditions. Effective polyrner-SPIO materials were screened for magnetic properties via a high-throughput (HT) magnetic resonance imaging (MRI) technique and nanoparticles were successfully tested for stability in buffer. It was found that the water-soluble SPIO nanoparticles could be tuned somewhat in terms of their MRI relaxivities via the specific ring-opening molecules used. To impart effective charge and steric stability of the water-soluble nanoparticles in buffer, the molecular weight, and chemistry of any given maleic anhydride copolymer was critical. Particle sizing via dynamic light scattering and cryo-transmission electron microscopy analysis showed significant discrepancies in the mean particle sizes obtained. This HT approach and the new amphiphilic polymers discovered have potential for use in various nanotechnology applications.