An Overview of Subnanosecond Pulsed Electric Field Biological Effects: Toward Contactless Technologies for Cancer Treatment

Abstract

During the last decades, millisecond, microsecond, and nanosecond electric pulses were all successfully used for both biological and medical applications. Among medical applications, irreversible electroporation (IRE) and electrochemotherapy (ECT) by microsecond pulsed electric fields (PEFs) are both minimally invasive established cancer treatments for superficial tumors, based on IRE or reversible electroporation combined with a therapeutic drug, respectively. The aim of this review is to summarize the present data, still rather scarce, on the biological effects induced by subnanosecond PEFs (sub-nsPEFs) following an approach “with contact.” A nonexhaustive overview of the effects of the nanosecond PEFs (nsPEFs) is also presented to foresee the possibilities offered by the application of sub-nsPEFs. Indeed, it is demonstrated that nsPEFs can indeed produce: permeabilization, followed by the transfer of molecules inside the cell; cell stimulation, with calcium mobilization through voltage-gated channels activation, and cell death. This review is extended to the medical applications of nsPEFs for cancer treatment in vivo, a procedure known as nanoablation. The long-term future for the PEF-based cancer treatment techniques implies a broadening of their applications to deep-seated tumors. This raises the challenge of overcoming the inherent invasiveness associated with the treatment of these tumors. A possible solution is the development of contactless ECT and IRE, noninvasive procedures that are possible only using highly sophisticated impulse antenna techniques. Thus, we also present existing contactless technologies recently developed worldwide and considered potential candidates for future biomedical applications. This review is therefore providing the community with a summary of the major “with contact” biomedical applications of sub-nsPEFs, while also exploring all the currently existing contactless technologies, by highlighting their importance in strengthening the role of PEFs in the fight against cancer.