Characterization of Platinum Electrodes and In-situ Cell Confluency Measurement Based on Current Changes of Cell-Electrodes

• Main Authors: Chin Fhong SOON, Mee Kei FOONG, Mohd Khairul AHMAD, Rosliza MD ZIN, Kok Tung THONG, Kian Sek TEE
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2015-04-01
• Series: Sensors & Transducers
• Subjects: Keratinocytes; Electric Cell-Substrate Impedance Sensor (ECIS); Cell confluency.
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/april_2015/Vol_187/P_RP_0197.pdf
• ISSN: 2306-8515; 1726-5479

This study aimed at the development of a biosensor to examine the growth confluency of human derived keratinocytes (HaCaT) cell lines in-situ. The biosensor consists of a sputter- coated glass substrate with platinum patterns. Cells were grown on the conductive substrates and the confluency of the cells were monitored in-situ based on the conductivity changes of the substrates. Characterization of the cell proliferation and confluency were interrogated using electrical cell-substrate impedance sensing (ECIS) techniques and current change of cells using a pico-ammeter. The investigation was followed by the electrical characterization of the platinum electrode (PE) using a two probe I-V measurement system. The surface morphology of platinum electrodes were studied using an atomic force microscopy (AFM) and the HaCaT cell morphology was studied using Field-Emission Scanning Electron Microscopy (FE-SEM). The microscopy results showed that the cells coupled and proliferated on the platinum electrodes. For monitoring the conductivity and impedance changes of the cell-electrode in-situ, the cover of a Petri dish was inserted with pogo pins to be in contact with the platinum electrodes. The impedance was sampled using the ECIS technique at a twenty-four hour interval. In our findings, the cell proliferation rate can be measured by observing the changes in capacitance or impedance measured at low ac frequencies ranged from 10 - 1 kHz. In good agreement, the current measured at micro-ampere range by the biosensor decreased as the cell coverage area increased over the time. Thus, the percent of cell confluence was shown inversely proportional to the current changes.