Cold atmospheric plasma (CAP) treatment is a rapidly expanding and emerging technology for cancer treatment. Direct CAP jet irradiation is limited to the skin and it can also be invoked as a supplement therapy during surgery as it only causes cell death in the upper three to five cell layers. However, the current cannulas from which the plasma emanates are too large for intracranial applications. To enhance efficiency and expand the applicability of the CAP method for brain tumors and reduce the gas flow rate and size of the plasma jet, a novel micro-sized CAP device (µCAP) was developed and employed to target glioblastoma tumors in the murine brain. Various plasma diagnostic techniques were applied to evaluate the physics of helium µCAP such as electron density, discharge voltage, and optical emission spectroscopy (OES). The direct and indirect effects of µCAP on glioblastoma (U87MG-RedFluc) cancer cells were investigated in vitro. The results indicate that µCAP generates short- and long-lived species and radicals (i.e., hydroxyl radical (OH), hydrogen peroxide (H₂O₂), and nitrite (NO₂⁻), etc.) with increasing tumor cell death in a dose-dependent manner. Translation of these findings to an in vivo setting demonstrates that intracranial µCAP is effective at preventing glioblastoma tumor growth in the mouse brain. The µCAP device can be safely used in mice, resulting in suppression of tumor growth. These initial observations establish the µCAP device as a potentially useful ablative therapy tool in the treatment of glioblastoma.

Glioblastoma is one of the most aggressive brain cancers. Chemotherapy is a standard modality for its therapy. Here, we demonstrated a novel strategy using a helium gas discharge tube as a tunable electromagnetic emission source to sensitize glioblastoma cells to the cytotoxicity of temozolomide (TMZ), a widely used drug for glioblastoma. After a single 7-min of treatment, the efficacy of TMZ was enhanced in two typical glioblastoma cell lines U87MG and A172 without affecting a normal human astrocyte cell line hTERT/E6/E7. The discharge tube is a non-invasive approach, which provides a safe, controllable, stable, and low-cost modality to improve the conventional chemotherapy.

Cold Atmospheric Plasma (CAP) has received heightened attention as an alternative therapy due to its ability to impact cancer cells and trigger the activation of apoptosis [1, 2]. Shockingly, there has been limited investigation of the real time effects of CAP on cell viability immediately following treatment. When measuring and continuously monitoring the immediate effects of CAP on breast and gastric cancer cells using a cell viability assay, it was seen that plasma induced cell death. The data revealed a decrease in cell viability for 15 minutes after plasma treatment, followed by increased cell viability for up to 60 minutes. These results were attributed to the rapid proliferation rate of cancer cells. CAP treatment decreased cell viability in a dose dependent manner, with treatment durations between 30-180 seconds. Treatment with CAP for 180 seconds resulted in the slowest upward trend in viability up to a maximum of 70% at 60 minutes post treatment. The most significant and permanent effects of CAP were observed at 24 and 48 hours post treatment.