Dear all

   Could you help me by answering the question or sharing me literature to explain the impedance phase change in using ECIS cell-based biosensor for monitoring cell attachment and spreading? Obviously, the impedance magnitude increases. However, the phase curve changes depending on frequencies. 

     In  my research, a cell monolayer was cultured on a square microelectrode (60x60 micrometer) for 1 day. The impedance was recorded in a frequency range from 100 Hz to 1 MHz. The impedance phase decreased sharply from -80 to -52 degree in frequencies from 100 Hz to 3 kHz. Then it increased up to approximately -70 degree in frequencies below 100 kHz. Finally from this frequency to 1 MHz, it was almost stable. 

Thank you so much for your help.