Enhanced mobility of neural cells with a transparent electric field stimulator.

Mobility is one of the important characteristics of living cells. It also plays a significant role in therapeutic cell transplantation with target location specificity. To enhance cell mobility, a neural cell stimulator was assembled with graphenes, which are two-dimensional nanocarbon materials that form a transparent electrode over the cover glass in a cell culture dish. This transparent stimulator applies electrical field stimulation to the neural cells. The advantages of this new transparent electrical field stimulator (TEFS) with a graphene electrode include transparency, because few layered graphenes are optically transparent, and biocompatibility, because the cover glass is coated with laminin. In this paper, it is reported that constant electric field stimulation, which is at a specific strength, facilitates the mobility of a neural cell and makes the visibility of cellular behavior on the electrode much better than that of any other existing cell stimulator that has metal electrodes. The strength of the electrical field for stimulating cells varies from 4.5 mV/mm to 450 mV/mm. When continuous electric field stimulation was applied for 4 hours at the electric field strength of 45 mV/mm, the mobility of the neural cells was significantly enhanced compared to the control conditions, wherein there was no electric field stimulation. Thus, the feasibility of the TEFS with the nanothickness of graphene was tested to modulate the mobility of neural cells in vitro. The result suggests that electrical field stimulation could enhance neural cell alignment, cell-to-cell coupling, and networks, and may be applied to cell transplantation to boost therapeutic effectiveness.

The control of neural cell-to-cell interactions through non-contact electrical field stimulation using graphene electrodes.

Electric field stimulation has become one of the most promising therapies for a variety of neurological diseases. However, the safety and effectiveness of the stimulator are critical in determining the outcome. Because there are few safe and effective in vivo and/or in vitro stimulator devices, we demonstrate a method that allows for non-contact electric field stimulation with a specific strength that is able to control cell-to-cell interaction in vitro. Graphene, a form of graphite, and polyethylene terephthalate (PET) was used to create a non-cytotoxic in vitro graphene/PET film stimulator. A transient non-contact electric field was produced by charge-balanced biphasic stimuli through the graphene/PET film electrodes and applied to cultured neural cells. We found that weak electric field stimulation (pulse duration of 10 s) as low as 4.5 mV/mm for 32 min was particularly effective in shaping cell-to-cell interaction. Under weak electric field stimulation, we observed a significant increase in the number of cells forming new cell-to-cell couplings and in the number of cells strengthening existing cell-to-cell couplings. The underlying mechanism of the altered cellular interactions may be related to an altered regulation of the endogenous cytoskeletal proteins fibronectin, actin, and vinculin. In conclusion, this technique may open a new therapeutic approach for augmenting cell-to-cell coupling in cell transplantation therapy in the central nervous system.