Single Cell Precision Microplasma Induced Cancer Cell Apoptosis

Tan X, Zhao S, Lei Q, Lu X, He G, Ostrikov K

Abstract

The issue of single-cell control has recently attracted enormous interest. However, in spite of the presently achievable intracellular-level physiological probing through bio-photonics, nano-probe-based, and some other techniques, the issue of inducing selective, single-cell-precision apoptosis, without affecting neighbouring cells remains essentially open. Here we resolve this issue and report on the effective single-cell-precision cancer cell treatment using the reactive chemistry of the localized corona-type plasma discharge around a needle-like electrode with the spot size ∼1 µm. When the electrode is positioned with the micrometer precision against a selected cell, a focused and highly-localized micro-plasma discharge induces apoptosis in the selected individual HepG2 and HeLa cancer cells only, without affecting any surrounding cells, even in small cell clusters. This is confirmed by the real-time monitoring of the morphological and structural changes at the cellular and cell nucleus levels after the plasma exposure.

Conclusion

In summary, we have demonstrated that individual HepG2 and HeLa cancer cells can be effectively inactivated via the single-cell-precision, microplasma-induced apoptotic response, while normal L-02 liver cells remain unaffected by the same plasma exposure. The microplasma can be confined to the small (∼1 µm) volume around the tip of a needle which can be positioned in any specific area by using a micromanipulator. The power delivered to the cell is very small (a few mW) yet sufficient to induce apoptosis selectively, without affecting neighboring cells, even within small clusters of closely contacting cells. The plasma source is battery-operated and does not rely on any external power or gas supplies, which may be particularly useful in situations where external power supply is not available or device portability is an issue.

This advance is generic and applicable to different types of cancer cells. It may lead to next-generation single-cell-precision microsurgeries. Step changes are also possible in the capability of addressable microarrays towards instantaneous inactivation of the as-detected malignant cells, where the needles in the arrays may be used as both the electrophysiological probes and the electrodes for the plasma generation.

Link: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0101299

DOI: 10.1371/journal.pone.0101299