Identification and characterization of soft protein corona absorbed on iron oxide nanoparticles

Nanomedicines have recently garnered significant attention due to their great potential to improve the efficiency of disease diagnosis and treatment. Nonetheless, a wide gap still exists between innovative research and clinical application because of limited understanding of the protein corona formed on the nanocarrier's surface. When NPs are introduced to living systems, the protein corona rather than the originally expected surface of the nanoparticle is initially recognized, further affecting immune clearance and tumor-specific delivery. This study found that after incubation with human plasma, the protein corona formed on the iron oxide nanoparticle's (IONP) surface significantly increased the uptake of IONPs in the leukemic cell line MOLM13. The formation and thicknesses of the protein coronas were measured by dynamic light scattering, nanoparticle tracking analysis, and flow cytometry, and the hard corona was measured by transmission electron microscopy. The size distribution of IONPs before and after incubation with plasma was measured, and the change in particle size was calculated to derive the thickness of the soft corona (7.58±3.94 nm) by subtracting the thickness of the hard corona from that of the full protein corona. The results can provide an approximation of the soft corona area after plasma incubation and contribute to the understanding of the features of the protein corona of nanoparticles with different physical and chemical properties.