Platinum Nanoparticles to Enable Electrodynamic Therapy for Effective Cancer Treatment

Abstract

Electrochemical therapy (EChT), by inserting electrodes directly into tumors to kill cancer cells under direct current (DC), is clinically used in several countries. In EChT, the drastic pH variation nearby the inserted electrodes is the main cause of tumor damage. However, its limited effective area and complex electrode configuration have hindered the clinical application of EChT in treating diverse tumor types. Herein, a conceptually new electric cancer treatment approach is presented through an electro-driven catalytic reaction with platinum nanoparticles (PtNPs) under a square-wave alternating current (AC). The electric current triggers a reaction between water molecules and chloride ions on the surface of the PtNPs, generating cytotoxic hydroxyl radicals. Such a mechanism, called electrodynamic therapy (EDT), enables effective killing of cancer cells within the whole electric field, in contrast to EChT, which is limited to areas nearby electrodes. Remarkable tumor destruction efficacy is further demonstrated in this in vivo EDT treatment with PtNPs. Therefore, this study presents a new type of cancer therapy strategy with a tumor-killing mechanism different from existing methods, using nanoparticles with electrocatalytic functions. This EDT method appears to be minimally invasive, and is able to offer homogeneous killing effects to the entire tumor with a relatively large size.

Keywords: electrochemical therapy (EChT); hydroxyl radicals; platinum nanoparticles; square-wave alternating current; tumor therapy.