Cell Viability Measurement Using a Portable Photodiode Array Chip
Joon Myong Song and Ho Taik Kwo
from: Lab-on-a-Chip Technology (Vol. 2): Biomolecular Separation and Analysis (Edited by: Keith E. Herold and Avraham Rasooly). Caister Academic Press, U.K. (2009)
Photodiode array (PDA) on-chip cell viability measurement is performed directly on the surface of PDA microchip. Cancer cells are treated with anticancer drugs such as naringenin (Nar), camptothecin (CAM) and sodium salicylate (Na-sal). The resultant apoptotic cells are then stained with trypan blue and spotted onto the surface of PDA microchip. This type of spotting eliminates the need of using complicated optical alignment, which is usually required for spectroscopic detection. The PDA microchip is used as a photodetector as well as a sample platform. PDA on-chip assay is based on the absorption detection of spotted cells. Light emitting diodes (LEDs) installed right above the PDA microchip produces red beam which reaches PDA microchip. Once the absorber is spotted on the surface of PDA microchip, the intensity of red beam which reaches PDA reduces as the amount of absorber increases. Trypan blue has a spectroscopic property to absorb the red beam. As the amount of trypan blue-stained cells increases, the PDA sense reduced intensity of red beam. Quantification of cell viability was accomplished using a calibration curve of red beam intensity versus the number of trypan blue-stained cells. The PDA on-chip cell viability measurement enables high-throughput measurement of optimal concentrations of different drugs against different cell lines in vitro read more ...