The schematic of the measurement system setup is shown in Figure . The in-phase magnitude of the current flow in response to AC stimulation was measured using a current follower and singlechip lock-in amplifier (AD630EVK) which was mounted on a Printed Circuit Board (PCB) board with pogo pin connectors, against which the sensing chip was clamped. An opening in the middle of the PCB enabled observation of the zoospores within the channel. A photo showing the PCB connector and the lock-in amplifier in presented in Figure . A camera with microscope lens (Thorlabs) was placed above the sensing chip, while an LED light was placed under the chip. The optical video was recorded simultaneously with the electrical recording; thus, the sensing signal could be correlated with the optical information. The lock-in amplifier output was AC-coupled to an oscilloscope (Picoscope 2000) to record the time variation of impedance.