Reactive oxygen species mediated-photo-sono-ablation of melanoma cells using a novel nanocomposite of platinum-polypyrrole as a nanozyme

Tumor eradication in non-invasive photothermal (PTT) and sonodynamic therapy (SDT) approaches is favorable in melanoma cancer. However, finding a sensitizer for synchronous PTT and SDT is a desirable request, especially if this sensitizer material has other benefits in tumor treatment. Here, a platinum (Pt)/polypyrrole nanocomposite (Pt@PPy NC) was introduced for synchronous synergistic PTT and SDT of melanoma cancer cells. To compare and clarify the effect of the nanocomposite components, platinum nanoparticles (NPs) and polypyrrole (PPy) NPs were also synthesized and evaluated. Pt@PPy NC consisted of near-spherical Pt NPs adhered by a network of PPy. Pt NPs, PPy NPs, and Pt@PPy NC had mean diameters of 13 ± 7, 177 ± 48, and 16.5 ± 2.5 nm, respectively. The results of cytotoxicity assessment of B16-F10 cells treated with Pt@PPy NC revealed that while it was cytocompatible, it represented enhanced photothermal and sonodynamic cytotoxicity (with a deeper cytotoxicity effect, compared to Pt NPs and PPy NPs). Cell viability assessments revealed that the cell killing ability was attained in a synergistic manner from the effects of Pt@PPy NC, 808-nm light, and ultrasound waves. Detection of intracellular reactive oxygen species (ROS) production revealed that the effect of PTT and SDT using Pt@PPy NC arose from induction of oxidative stress. Pt@PPy NC also represented catalase-mimicking activity and could be considered for combination therapy.