The number of cells counted using neobar lam (hemocytometer) also showed that the lower the concentration of collagen thin films, the higher the number of cells after 48 h. Results are shown in Fig. 3 (B).
Fig. 5: The differential bioimpedance of the cells (A) the MSCs, and (B) the HUVECs cultured on the collagen thin films with different concentrations, 48 h after their seeding.3.2.2 Bioimpedance phase of the MSCs cultured on the collagen thin film
The differential phase (\(\varphi\)) diagrams of the measured bioimpedance of the cultured MSCs on the collagen thin films with different concentrations over time are shown in Fig. 6 (A-C). As shown in these graphs, for all concentrations of collagen thin films, the impedance phase has become more negative over time, indicating the attachment and growth of cells over time. The lower the concentration of the collagen thin films, the greater the amount of this negativity, showing the higher number of the cells inside the wells. In other words, from the measured impedance phase, it can be seen that over time, the cells have more attachment and proliferation rate on the collagen thin films with lower concentration with respect to higher concentrations, which makes the phase of bioimpedance more negative.