Protein Corona Formation on Magnetic Nanoparticles Conjugated with Luminescent Europium Complexes

Abstract The evaluation of the nanoparticles interactions with blood plasma enables a first and important insight on the organization of the adsorbed protein layer. In this context, we studied the formation of protein corona on magneto‐luminescent Fe₃O₄@calix‐Eu(TTA) nanoparticles in human plasma. The difference in the surface chemistry of F₃O₄ functionalized with calixarene (+30 mV ζ‐potential) and europium (III) thenoyltrifluoroacetonate (Eu³⁺‐TTA) complex (+7.4 mV ζ‐potential) affected the colloidal stability and hard corona composition of the nanoparticles, which were monitored by SDS‐PAGE gel electrophoresis, differential centrifugal sedimentation analyses and luminescence spectroscopy. Strikingly, after conjugation with Eu³⁺ TTA complex, the magnetic nanoparticles show lower adsorption affinity to proteins at higher blood plasma concentration. Moreover, the Eu³⁺ compound is featured with the narrow emission lines of ⁵D₀→⁷F_J (J=0–4) transitions, imparting additional characteristics to bifunctional nanoparticles that were used as probes to evaluate the protein corona formation.