The mechanisms of cell death due to electroporation are still not well understood. Recent studies suggest that cell death due to electroporation is not an immediate all-or-nothing response but rather ...a dynamic process that occurs over a prolonged period of time. To investigate whether the dynamics of cell death depends on the pulse parameters or cell lines, we exposed different cell lines to different pulses monopolar millisecond, microsecond, nanosecond, and high-frequency bipolar (HFIRE) and then assessed viability at different times using different viability assays. The dynamics of cell death was observed by changes in metabolic activity and membrane integrity. In addition, regardless of pulse or cell line, the dynamics of cell death was observed only at high electroporation intensities, i.e., high pulse amplitudes and/or pulse number. Considering the dynamics of cell death, the clonogenic assay should remain the preferred viability assay for assessing viability after electroporation.
We propose and demonstrate a sensitive diagnostic device based on an Organic Electrochemical Transistor (OECT) for direct in-vitro monitoring cell death. The system efficiently monitors cell death ...dynamics, being able to detect signals related to specific death mechanisms, namely necrosis or early/late apoptosis, demonstrating a reproducible correlation between the OECT electrical response and the trends of standard cell death assays. The innovative design of the Twell-OECT system has been modeled to better correlate electrical signals with cell death dynamics. To qualify the device, we used a human lung adenocarcinoma cell line (A549) that was cultivated on the micro-porous membrane of a Transwell (Twell) support, and exposed to the anticancer drug doxorubicin. Time-dependent and dose-dependent dynamics of A549 cells exposed to doxorubicin are evaluated by monitoring cell death upon exposure to a range of doses and times that fully covers the protocols used in cancer treatment. The demonstrated ability to directly monitor cell stress and death dynamics upon drug exposure using simple electronic devices and, possibly, achieving selectivity to different cell dynamics is of great interest for several application fields, including toxicology, pharmacology, and therapeutics.
Alternating electric (AC) fields are known to activate tumor cell death, but the underlying cellular mechanisms are poorly understood. We thus combined live-cell imaging with computational modeling ...to investigate the dynamic interactions between AC fields and cultured mammalian cells. Our results showed extensive cell death activated via two distinct mechanisms. At frequency range of 100–300kHz and 800–1000kHz, AC fields triggered prolonged mitotic arrest followed by apoptosis, and the cell death kinetics showed linear dependence on both field frequency and intensity. However, at intermediate frequencies, from 300kHz to 800kHz, cells died as a result of field-induced surface detachment, and the process exhibited a resonance frequency. Based on models of induced dielectric polarization and charge oscillation, we simulated the functional dependence of cell death kinetics on field frequency and intensity for both the linear and resonance response regimes. By comparing the simulated and experimental results, we not only determined the crucial electrical properties of mammalian cells that govern their interaction with AC fields but also acquired novel mechanistic understanding of the resulting cell death processes, which provides important new insight for potentially utilizing AC fields as an alternative anti-tumor remedy.
•AC fields induced cancer cell death via distinct frequency-dependent mechanisms.•Death due to field-induced loss of surface adhesion exhibited resonance features.•Death due to field-induced prolonged mitotic arrest exhibited a linear response.•The two response mechanisms were quantitatively modeled and simulated.
