Effect of Surface Modifications on Cellular Uptake of Gold Nanorods in Human Primary Cells and Established Cell Lines

Abstract

Endocytosis is a cellular process in which substances are engulfed by the cellular membrane and budded off inside the cells to form vesicles. It plays key roles in controlling nutritional component uptake, immune responses, and other biological functions. A comprehensive understanding of endocytosis gives insights into such physiological functions and informs the design of medical nanodevices that need to enter cells. So far, endocytosis has been studied mostly using established cell lines. However, the established cell lines generally originate from cancer cells or are transformed from normal cells into immortalized cells. Therefore, primary cells may give us more reliable information about the endocytosis process of nanoparticles into cells. In this research, we studied the uptake of gold nanorods (AuNRs) with four different surface modifications (anionic/cationic polymers and anionic/cationic silica) by two kinds of primary cells (human monocyte-derived macrophages and human umbilical vein endothelial cells) and two kinds of established cell lines (HeLa cells and RAW 264.7 cells). We found that the surface properties of AuNRs affected their cellular uptake, and the cationic surface tended was advantageous for uptake, but it depended on the cell types. Control experiments using inhibitors of representative endocytosis pathways (macropinocytosis, clathrin-mediated endocytosis, and caveolae-mediated endocytosis) indicated that primary cells had a dominant uptake pathway for internalization of the AuNRs, whereas the established cell lines had multiple pathways. Our results provide us with novel insights into cellular uptake of AuNRs in that they depend not only on surface characters of the nanoparticles but also cell types, such as primary cells and established cell lines.

On the Cellular Uptake and Exocytosis of Carbon Dots─Significant Cell Type Dependence and Effects of Cell Division

“…Physicochemical properties of NPs, including their shape, size, surface ligand, and so forth, are crucial factors influencing the cellular uptake and exocytosis processes of the NPs. ,− Different cells have different properties and functions, ,− so their responses to different NPs may also be different. For example, cells of different types adopt different endocytic pathways to ingest the same NPs, resulting in different biological effects, for which an example is the higher content of NPs in lysosome destroyed the integrity of the lysosomal membrane. − Different types of cells may also have different proliferation rates, which are correlated with different changes in the cellular content of NPs, with the intracellular NPs almost equally distributed into daughter cells after the cell division. ,, Therefore, the cell type must be a pivotal factor affecting the cellular uptake and exocytosis processes of NPs, as recognized in some reported studies. ,,− Further more systematic investigations on the exocytosis of NPs in cells aimed at an understanding of the cell-type dependence are in demand …”

Synthesis of Silica Nanoparticles with Physical Encapsulation of Near-Infrared Fluorescent Dyes and Their Tannic Acid Coating

“…To investigate whether the fluorescence of OXA@SiO 2 @TA NPs can be observed in the cells, OXA@SiO 2 @TA NPs were introduced into the COS-7 cells with lipofectamine 2000, which is the most commonly used cationic lipid transfection reagent . The surface charge of NPs can affect the cellular uptake efficiency by changing the adhesion and interaction of NPs with the cell membrane. , Generally, NPs with higher positive charge exhibit a stronger affinity for the negatively charged cell membrane. , Therefore, cationic lipofectamine 2000 was introduced to the surface of negatively charged silica NPs . Then, the COS-7 cells were cultured in Dulbecco’s modified Eagle’s medium with 10% fetal bovine serum at 37 °C under 5% humidified CO 2 for 1 day.…”

“…56 The surface charge of NPs can affect the cellular uptake efficiency by changing the adhesion and interaction of NPs with the cell membrane. 57,58 Generally, NPs with higher positive charge exhibit a stronger affinity for the negatively charged cell membrane. 59,60 Therefore, cationic lipofectamine 2000 was introduced to the surface of negatively charged silica NPs.…”

Gold Nanorods-Based Photothermal Therapy: Interactions Between Biostructure, Nanomaterial, and Near-Infrared Irradiation

“…AuNRs enter cells via endocytosis, and their surface modification and the cell type affect the endocytic pathway, with cell type playing a preferential role. The cellular uptake of AuNRs is also influenced by serum proteins and cell surface coating status [ 42 , 43 ]. In contrast to neutral and negatively charged AuNRs, positively charged AuNRs undergo extensive aggregation when exposed to isolated human skin [ 44 ].…”