Effect of surface chemistry and associated protein corona on the long-term biodegradation of iron oxide nanoparticles in vivo

Resumen del trabajo presentado a la 12th International Conference on the Scientific and Clinical Applications of Magnetic Carriers, celebrada en Copenhague (Dinamarca) del 22 al 26 de mayo de 2018.
Once a nanoparticle (NP) is administered in vivo, it interacts with the components of the physiological environment, especially with proteins, resulting in the formation of the so-called protein corona (PC). PC can dramatically change the nanomaterial size, aggregation state, and interfacial properties, dominating in an uncontrolled way the biological behaviour of NPs. Although it is widely accepted that the presence of this PC would ultimately determine the fate of the nanomaterial, its role in the biotransformation and degradation of NPs in vivo has been scarcely investigated. Here we report how the surface modification of identical superparamagnetic iron oxide NPs with either glucose (Glc) or poly(ethylene glycol) (PEG) affects the PC identity, the NPs biodistribution, and more importantly, the degradation over time. Although NPs@Glc and NPs@PEG bound similar amount of proteins in vitro, the differences found in the composition of both PCs corresponded to the NPs biodistribution in vivo. Whereas NPs@Glc were mostly accumulated in the liver and spleen, NPs@PEG were detected in various organs, including thymus or reproductive system organs. Moreover, by employing magnetic measurements we have found that the biodegradation kinetic and therefore clearance of both NPs types was unequal, as NPs@PEG core suffered a faster degradation over time than NPs@Glc, in both liver and spleen. Differences in the degradation rate observed in vitro and in vivo could be related not only with the attached molecules, but also with the associated PC, which composition may directly affect the degradation rate by lysosomal enzymes or indirectly by driving NPs accumulation in different cells.