What SAXS Can Tell About Magnetic-Nanoparticle Cell Interactions

DIEGO F. CORAL; PAULA ANDREA SOTO; DE SOUSA,M.ELISA; MENDOZA ZÉLIZ, PEDRO; C.P.SETTON-AVRUJC; FERNANDEZ VAN RAAP, MARCELA

CAMPINAS

Conferencia; XVIII edition of the International Small-Angle Scattering Conference (SAS2022); 2022

Brazilian Center for Research in Energy and Materials (CNPEM)

Magnetic iron oxide nanoparticles (NPs) are under analysis for several medical applications. The most relevant are diagnosis,cancer therapy and tissue regeneration. Once incorporated in the body the NPs responds to various intended and non-intendedstimuli like pH variations, drag forces, light and magnetic field applications and chemically interact with molecules and proteins.The intended stimuli are used to make the NPs exert therapeutic actions such as magnetic hyperthermia and photo plasmonichyperthermia. The non-intended stimuli are related to the interaction of the NPs with different biological environments andspecially with cells where they get internalized, confined in cell endosomes, and may later be dissolved and release iron ionswhich may integrate to metabolic pathways or induce toxicity. In this context, access to detailed information on cells loaded withnanoparticles with nanoscale precision is of a long-standing interest in many areas of nanomedicine. Thus, designing a singleexperiment able to provide statistical mean data from a large number of living unsectioned cells concerning information on thenanoparticle size and aggregation inside cell endosomes and accurate nanoparticle cell up-take is of paramount importance.Small-angle X-ray scattering (SAXS) is a valuable tool to achieve such relevant data. Experiments were carried out in culturesof B16F0 murine melanoma and A549 human lung adenocarcinoma cell lines loaded with various iron oxide nanostructuresdisplaying distinctive structural characteristics. Five systems of water-dispersible magnetic NPs of different size, polydispersityand morphology were analyzed, namely, nearly monodisperse NPs with 11 and 13 nm mean size coated with meso-2,3-dimercaptosuccinic acid, more polydisperse 6 nm colloids coated with citric acid and two nanoflowers (NF) systems of 24 and27 nm in size resulting from the aggregation of 8 nm NPs. Up-take was determined for each system in B16F0 cells. We will showthat SAXS pattern provides high resolution information on nanoparticles disposition inside endosomes of the cytoplasm throughthe structure factor analysis, on nanoparticles size and dispersity after their incorporation by the cell and on up-take quantificationfrom the extrapolation of the intensity in absolute scale to null scattering vector. We will also report on the cell culture preparationto reach sensitivity for the observation of NPs inside cell endosomes carrying out SAXS with a high brightness synchrotronsource. Our results show that SAXS can become a valuable tool for analyzing NPs in cells and tissues