Biological, Medical, and Agricultural Applications of Plasmas I

It is well known that cells respond to external stimulation. Scientists and researchers have been using various stimulations (chemical, electrical, optical, and mechanical stimulations, etc.) for guiding cell fate. Supplying appropriate stimulations is a key for creating cells useful for human.

 

Recently, non-thermal atmospheric pressure plasma has been used for controlling life activities of cells. When a plasma is generated under atmospheric conditions, plasma reacts with ambient air generating reactive oxygen and nitrogen species (RONS). Those RONS can be used to control cells. Thus far, promoted cell proliferation and selected cell killing has been reported as well as promotion of cell differentiation.

 

To achieve precise cell control using plasma, we developed a microdevice system referred to as Plasma-on-Chip [1,2]. The Plasma-on-Chip system consists of a microwell chip and an atmospheric pressure plasma source.

 

The microwells are fabricated by deep reactive ion etching of a Si chip. Each microwell (Φ400 mm) has through-hole at the bottom. Depending on the design, through-holes ranged from Φ5 mm to Φ30 mm. The microwell chip is sandwiched by two PTFE cases forming liquid reservoir. The setup is placed on a planer Dielectric Barrier Discharge (DBD) plasma source [3].

 

When a medium containing cells is poured into the liquid reservoir, the medium is supplied into the microwell and the surface tension of the medium forms air-liquid interface at each through-hole holding liquid medium in each microwell. After incubation, cells are diffused seeded in microwells. When DBD plasma is generated, RONS pass through the through-holes and the gas-liquid interface and reach the cells in the microwells. Therefore, Plasma-on-Chip system enables direct plasma exposure of cells.

 

In this talk, principle of Plasma-on-Chip device system and latest results for biomedical research will be presented.

Acknowldgement: We appreciate Cell Bank, Riken, Japan for distributing cells.

Funding acknowledgement

The Takahashi Industrial and Economic Research FoundationThe joint usage/research program of Center for Low-temperature Plasma Sciences, Nagoya University, Japan.The RIKEN BRC through the National Bio-Resource Project of the MEXT, Japan.