The Effect of shape on Cellular Uptake of Gold Nanoparticles in the forms of Stars, Rods, and Triangles

Abstract

Gold nanomaterials have attracted considerable interest as vehicles for intracellular drug delivery. In our study, we synthesized three different shapes of methylpolyethylene glycol coated-anisotropic gold nanoparticles: stars, rods, and triangles. The cellular internalization of these nanoparticles by RAW264.7 cells was analyzed, providing a parametric evaluation of the effect of shape. The efficiency of cellular uptake of the gold nanoparticles was found to rank in the following order from lowest to highest: stars, rods, and triangles. The possible mechanisms of cellular uptake for the three types of gold nanoparticles were examined, and it was found that different shapes tended to use the various endocytosis pathways in different proportions. Our study, which has demonstrated that shape can modulate the uptake of nanoparticles into RAW264.7 cells and that triangles were the shape with the most efficient cellular uptake, provides useful guidance toward the design of nanomaterials for drug delivery.

Figure 1

Schematics of gold nanostar, gold nanorod and gold nanotriangle loading into mPEG.

Figure 2

Photographs, UV-Vis spectra, TEM and 3D AFM images of GNSs (A,D,G,J), GNTs (B,E,H,K) and GNRs (C,F,I,L).

Figure 3

Size and zeta potential of GNPs and P-GNPs: Size of GNSs, GNTs, GNRs(A,B,C), Size of P-GNSs, P-GNTs, P-GNRs(D,E,F), Zeta potential of GNSs and P-GNSs(G), GNTs and P-GNTs (H), GNRs and P-GNRs (I).

Figure 4

Relative viabilities of RAW 264.7 after being incubated with various concentrations of P-GNPs for 24 h, as determined using CCK8 assays. Data represent mean ± SEM (n = 3).

Figure 5

Cellular uptake of P-GNPs(A) and TEM images of RAW 264.7 after 24 h of incubation with P-GNSs(B), P-GNRs(C), P-GNTs(D). Data represent mean ± SEM (n = 3). Statistical significance is represented by *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 6

Uptake % of P-GNSs (A), P-GNRs (B) and P-GNTs (C) (compared to the positive controls) in the present of different endocytic inhibitors in the RAW264.7 cells. Error bars represent standard deviation. *p < 0.05, **p < 0.01, ***p < 0.001 compared to the control. (D)Summary of cellular uptake inhibition of P-GNPs in the present of endocytic inhibitors. +p < 0.05; ++p < 0.01; +++p < 0.001; – no significant inhibition.