Study of toxicity and cellular uptake of magnetic nanoparticles with different coatings

VICO RAQUEL V.; SELZER SOLANGE M.; FERREYRA NANCY F.; BONNET LAURA V.

Venecia

Otro; Green Chemistry Summer School 2021; 2021

Currently, magnetite nanoparticles (MNP) are widely studied for their possible applications in numerous biotechnological fields, such as separation and recycling, (bio) detection, (bio) catalysis, and also in the biomedical area. Their biocompatibility, relatively low toxicity, superparamagnetism (in a size range of 10-20 nm), and versatility for surface modification make these nanomaterials suitable for the areas mentioned above [1]. Nanoparticles´ high surface/volume ratio allows incorporating a large number of molecules, which give them colloidal stability, biorecognition specificity and modulate their interaction with proteins and cell membranes [2]. In the context of biotechnological application, it is necessary to analyze the interactions between MNP and cells; however, there are relatively few studies that correlate the physicochemical properties of these nanomaterials and their influence on cell interactions and the toxic effect that they can produce. In order to carry out the functionalization of nanoparticles with biomolecules (carbohydrates or proteins) that will act as a recognition element for sensing, an accessible surface chemistry is necessary. In this work, we synthesized pristine magnetite nanoparticles (MNPs) and magnetite nanoparticles functionalized with the chemical groups, amino (MNP-Ar-NH2) and carboxylic acid (MNP-Ar-COOH). The nanoparticles were characterized to stablish the size, surface coverage, charge and zeta potential. The cytotoxicity and cellular uptake of each type of nanoparticles were compared. For this purpose, Chinese hamster ovary (CHO- K1) cells were used as a model to assess cellular viability by using the Alamar Blue reagent. In the range evaluated, up to 0,5 mg/mL, nanoparticles did not significantly affect cell viability. Cell uptake studies were performed by confocal microscopy on HeLa cells which stably expressed the autophagic protein LC3B fused to the green fluorescent protein (GFP). The results obtained showed a higher internalization of MNP-Ar-NH2 compared to MNPs and MNP-Ar-COOH. Moreover, we observed an increase in LC3B (+) vacuoles which correlates with an activation of autophagy to promote MNPs degradation. This reveal how the initial surface properties of nanoparticles conditioned the interactions with the components of the culture media, represented mainly by proteins, and this is extrapolated to the interaction with cells. It is well known that the protein corona changes the chemical identity of the nanoparticles, therefore when the cellular uptake occurs the dynamic of internalization might be different to each nanoparticle.