Taste Cell Chip And Its Application In Taste Transduction Mechanism

Though taste is one of the important sensations, the intrinsic perception process of taste is far less known than those of vision, audition, touch and olfaction. Moreover, methods of the electronical signals recording of taste cell mainly depends on the microelectrode or the patch clamp sticking to the membrane of the cells. It is difficult for those techniques to realize long-term monitoring of taste cells, especially, the multi channels synchronous recording of cellular networks due to unavoidable damage to cells. Therefore, using microelectromechanical systems, researchers have developed cell chips based on microelectrode array (MEA), field effect transistor (FET) array and light addressable potentiometric sensor (LAPS) in order to record the extracellular potentials of cells in a non-invasive way. Being an in vitro recording system, cell chip means a technique of culturing excitable cells such as cardiac cells or neurons on the surface of cell chip, where cells can couple with electrodes or gates of FET through a thin layer of electrolyte. Thus, the electrical activities of excitable cells can be monitored in vitro by the novel biochip in a long-term and non-invasive way. With these merits, cell chips have been applied widely to biomedical studies such as electrophysiology, drugs screening and environment detection.Combined with the previous studies on artificial taste and cell-based biosensor in our laboratory, we provides a novel taste cell chip based on LAPS since taste receptor cells are excitable similar to neurons. Taste cells are cultured on the LAPS chip for several days and then the change of extracellular signals can be detected by measuring the change of LAPS photocurrent. Compared with MEA and FET array, LAPS chip is easier to fabricate and allows us to track taste cells cultured randomly and locate it to desirable site taking advantage of light-addressability of LAPS.With the microelectromechanical technique, we developed the taste cell chip based on LAPS, the surface of which had already been soaked in the phosphate-buffered saline with 100μg/ml poly-L-ornithine and 8μg/ml laminin to enhance the attachment of cell on it. Using micropipette, the taste buds were successfully isolated from rat tongue epithelium and then placed on LAPS chip. Firstly, we selected norepinephrine (NE) and tetrodotoxin (TTX) as stimulative drugs to elicit action potentials of taste cell and inhibit taste cellular potential respectively. The experimental results proved the possibility of monitoring AP change of taste cell using LAPS chip. Subsequently, wemonitored the LAPS response after four basic tastants (NaCl, HCI, Sucrose and MgSCU) have been applied on the taste cell cultured on the chip. Experimental data were acquired by LabVIEW and processed through the time-domain analysis and frequency-domain analysis with Matlab. We analyzed qualitatively the specific effect of different tastants and proved the sensitivity to salt and sourness of taste receptor cells isolated from rat fungiform papilla. These experimental results demonstrate the feasibility that the cell chip based on LAPS can be used in the study of taste transduction mechanism. -...