The Alternating Current Scanning Electrochemical Microscopy Characterization of Diatom Cell Activity Affected by Paeonol

The alternating current scanning electrochemical microscopy (AC-SECM) is an important method to characterize the electrochemical activity of living cells. In this paper, we apply AC-SECM to measure the electrochemical activity of diatom biofilm. We find that the diatom biofilm presents insulating effect to decrease the current, when the electrode is close to the biofilm. The alternating current impedance of diatom biofilm is overall smaller than that of the bare glass. To investigate the possible effect of chemical stimulus on cellular activity, the diatoms were immersed into paeonol solution (100 μg/mL), and AC-SECM imaging experiments were conducted when immersion time reached 20 h, 25 h and 35 h. The AC measurements performed at high frequencies show that phase angle decreases over time, which preliminarily indicates that the cellular activity of diatoms is affected by paeonol.