THE IMPORTANCE OF COLLOIDAL STABILITY IN NANOPARTICLE-CELL INTERACTION

Córdoba Capital

Congreso; LI Reunión anual de la Sociedad Argentina de Biofísica; 2023

Iron oxide nanoparticles (IONPs) are one of the most studied nanomaterials for nanobiotechnology applications. Their physicochemical properties make them highly efficient for biomedical applications, such as contrast agents for diagnostic imaging, drug delivery vehicles, and photothermal therapies, among others [1]. Surface functionalization of IONPs is the main strategy to achieve the required properties for a given application. This strategy allows not only to increase the colloidal stability by avoiding their agglomeration, but also to control or modulate their internalization and intracellular fate [1,2]. Size and surface chemistry of nanoparticles have been shown to be the main determinants of their cellular uptake and effects (toxic or non-toxic). These properties determine the composition of the protein corona that forms on the IONPs when they come into contact with biological media and, consequently, how the nanoparticles enter cells. In addition, the induction of cytotoxicity is determined by the route of internalization and intracellular localization of the nanoparticles, which is why nanoparticle-cell interactions have become an extremely active area of research in biotechnological application [2]. In this context, we studied the colloidal stability of non-functionalized magnetite nanoparticles (MNPs) exposing hydroxyl groups or functionalized with aryls exposing carboxylic (MNP-Ar-COOH) or amino (MNP-Ar-NH2) groups in different dispersion media, with and without proteins, and correlated such stability with cell internalization capacity, autophagy activation and cell viability. The nanoparticles were characterized to stablish the size, surface coverage, 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 LC3II fused to the green fluorescent protein (GFP). The results obtained showed a higher increase in LC3II (+) vacuoles, which correlates with an activation of autophagy to promote MNPs degradation, on cells treated with MNPs compared to MNP-Ar-NH2 and MNP-Ar-COOH. This higher activation in addition, was correlated with a higher amount of MNPs that were capture by cells as a consequence of their lower colloidal stability regards with functionalized nanoparticles. 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. 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. [1] Sachdeva, V. et al. Iron Oxide Nanoparticles: The Precise Strategy for Targeted Delivery of Genes, Oligonucleotides and Peptides in Cancer Therapy. J. Drug Deliv. Sci. Technol. 2022, 74, 103585.[2] Natarajan, P. et al. Understanding the Influence of Experimental Factors on Bio-Interactions of Nanoparticles: Towards Improving Correlation between in Vitro and in Vivo Studies. Arch. Biochem. Biophys. 2020, 694, 108592.