Real time estimation of stem cell zeta potential and dimension during proliferation using MoS<inf>2</inf> nanosheets field effect transistor

In this paper, we demonstrate a unique FET system composed of vertically aligned MoS2nanosheets for real time, label free monitoring of zeta potential and dimension of mesenchymal stem cells during proliferation. To avoid the interference from non-specifically adsorbed macromolecules, a time varying electric field with an optimized frequency of 10 kHz has been applied at the gate and effective gate bias has been estimated from the real time drain current measurement in an electrical double layer gated cell-coupled FET platform. Special signal patterns corresponding to the alterations in the cell membrane potential have been observed. Extraction of cell parameters from the experimental observations, using closed set of equations reveal that the results correlate well with the gold standards and a high transconductance has enabled tracking of cell count with sufficient accuracy. The MoS2 FET signal has been compared with the pH change of the cell culture medium and the signal follows the cell proliferation related activity more closely than the pH change. Thus, it may be expected that this platform can substitute the existing time consuming and laborious methods.