Influence of Cell Type on the Efficacy of Plasmonic Photothermal Therapy

Abstract

In plasmonic photothermal therapy (PPTT), illuminated gold nanoparticles are locally heated to produce selective damage in cells. While PPTT is expected to strongly depend on the cell line, available data are sparse and critical parameters remain unclear. To elucidate this pivotal aspect, we present a systematic study of diseased and nondiseased cells from different tissues to evaluate cytotoxicity, uptake of gold nanorods (AuNRs), and viability after PPTT. We identified differences in uptake and toxicity between cell types, linking AuNR concentrations to toxicity. Furthermore, the cell death mechanism is shown to depend on the intensity of the irradiated light and hence the temperature increase. Importantly, the data also underline the need to monitor cell death at different time points. Our work contributes to the definition of systematic protocols with appropriate controls to fully comprehend the effects of PPTT and build meaningful and reproducible data sets, key to translate PPTT to clinical settings.

Figure 1

Uptake of AuNR-PEG as a function of concentration for different cell lines. *p < 0.05, error bars represent SEM (n = 3–6). No statistical differences were observed between all conditions for Hek293 and 0–1 nM for THLE-3.

Figure 2

Effect of AuNR-PEG concentration on cellular viability. (A) Viability of cell lines for all studied concentrations shown as percent of controls (0 nM). (B) IC₅₀ of cell lines. ***p < 0.001. Error bars represent SEM (n = 4).

Figure 3

Temperature dynamics in +AuNR-PEG and ⌀AuNR cells upon irradiation. (A) Increase in temperature as a function of time for cell lines irradiated 3 min with an 808 nm laser light at 3 W/cm². Continuous line indicates cells with AuNR-PEG (+AuNR-PEG) and dotted line cells without AuNR-PEG (⌀AuNR-PEG). Shaded line represents the SEM. (B) Averaged absolute increases of temperature of cells + AuNR-PEG.

Figure 4

Cellular viability (%) after treatment assessed with MTT assay. (A–F) Viability at 0 and 24 h after irradiation in control (CTL) and in cells irradiated with AuNR-PEG (+AuNR-PEG) and without (⌀AuNR-PEG). (G) Statistical comparison for each cell line at different time points between conditions from panels (A) to (F). Differences between 0 and 24 h are shown in the graphs. Statistical comparisons were made using Tukey/Wilcox post hoc tests. *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001; ns, not significant.

Figure 5

Cellular viability (%) after treatment assessed with Trypan Blue staining. (A–F) Viability at 0 and 24 h after irradiation in control (CTL) and in cells irradiated with AuNR-PEG (+AuNR-PEG) and without (⌀AuNR-PEG). (G) Statistical comparison for each cell line at different time points between conditions from panels (A) to (F). Differences between 0 and 24 h are shown in the graphs. Statistical comparisons were made using Tukey/Wilcox post hoc tests. *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001; ns, not significant.