A simple assay for probing transformations of superparamagnetic iron oxide nanoparticles in human serum.

A novel approach for monitoring the biomolecular interactions of superparamagnetic nanoparticles was disclosed. Based on ultrafiltration of a human serum-nanoparticle mixture and the mass spectrometric analysis of filtrates, this assay revealed for iron oxide nanoparticles coated with poly(acrylic acid) satisfactory biopersistence and a bimodal binding to sulfur-containing biomolecules, with the formation of the protein corona completed in about 1 h.