Bitter Taste Response Character Of Frequency Modulation In Taste Cell-Based Sensor

Gustation is one of the basic human feelings and an important physiological sensation owned by both human beings and animals for recognizing environmental conditions. Great research enthusiasm about the artificial intelligence sensory has been caused because of the high sensitivity of taste receptors to taste substance. The recent advance in sensor technology leads to the development of taste cell-based sensor.The sensor treats taste receptor cells as the sensitive element, which can collect and process the physiological and biochemical signals produced by the taste substance stimulating taste cell, so as to distinguish and identify the corresponding response information produced by the different kinds and concentration of the taste substance solution. There are big differences between taste cell sensor and general bionic taste sensor (electronic tongue) in the mechanism of feelings, as taste cell-based sensor’s biometric identification is through the direct interaction of odorants with taste receptor cells.In our previous work, a set of bitter taste cell sensor based on STC-1cell had been proposed to study the identification response of a series of bitters and mixed bitter solutions in1KHz fixed frequency. However, the taste quality response signal characteristics in a single frequency could not fully cover the response characteristics of the sensor, which greatly affected the transformation process of the taste cell sensor into the actual application. In that case, it was necessary to do in-depth research on the influence of taste cell sensor response characteristics excited by changing signal frequency condition. The research results are shown as follows:1. Construct the bitter receptor cell sensor sensitive elementThe expression of taste transduction function factor of a-gustducin、 PLCβ2、TRPM5in STC-1cells and mouse taste bud cells had been demonstrated by immunohistochemistry and Western Blot experiments. Subsequently, the existence of STC-1cells and mouse taste bud cells cultured on the electrode surface were characterized by scanning electron microscope, and the results showed that the cells had normal form and attached good in the electrode. Finally, culturing STC-1cell in the incubator external through simulating the condition of electrode using the glass slide coated with PLL, the experiment proved that the cytoactive was good in the whole experimental period, which could meet the experiment request.2. Methods of response characteristics of the bitter taste sensor by the frequency modulationThe experimental methods of STC-1cell sensor and mouse taste buds cell sensor controlled by the frequency mainly included:28excitation signal frequency from100Hz-10000Hz was divided into3parts, low frequency, intermediate frequency and high frequency. Four tastants (cycloheximide, quinine, phenylthiourea, propylthiouracilum) were chose as representative bitter tastants according to the interaction relations between the taste receptors and bitter ligands. Seven concentrations of each solution were set up according to the sensory threshold, as well as the blank control group. Stochastic resonance was adopted as data processing methods. The experiment results demonstrated that STC-1cells and mouse taste buds cells with bitter taste receptor or corresponding bitter taste transduction factors could response characteristically to the stimulation of bitter substances under different frequencies, with good feasibility and reliability.3. Study on response characteristics of bitter taste cell sensor by frequency regulationThe phenomenon of bitter taste cell-based sensor cultured STC-1cells and mouse taste bud cells in response to representative bitter tastants in a wide range of excitation signal frequency modulation was described. The concludes stemming from these phenomenon are follows:(1) Universality of sensor character response:The bitter taste-based sensor using STC-1cells and mouse taste bud cells as sensitive element almost had characteristic responses in a wide range of excitation signal frequency disturbance range, which showed that the sensor proposed had wide detection frequency range.(2) Specific of sensor character response:Each characteristic peak type from the interaction of the cells with bitter tanstants had the best nickelodeon. The characteristic peak type of bitter response signal of cycloheximide showed obvious and best in the intermediate frequency (1100Hz-2000Hz) range. Likewise, the characteristic peak type of response signal of Quinine stimulating STC-1cells showed obvious and best both in the low frequency (500Hz-1000Hz) and intermediate frequency (1100Hz-2000Hz) range. The characteristic response signals irritated by phenylthiourea and propylthiouracil to STC-1cells were similar and had good peak type in almost all of the frequency range.(3) Sensor character response has mobility:In stochastic resonance processing results under the exciting signal disturbance with different frequency, signals produced by the bitter substances stimulating the cells changed with the frequency and the noise intensity of the peak position increased with frequency increasing. It was showed that the response characteristics of the same kind of bitter substances under the different frequency disturbance were different. 4. Reason analysis of sensor characteristic responseThe phenomenon appeared in the experiment was analyzed from three aspects of taste receptor ligands interaction relations, intracellular calcium oscillation and cell impedance spectrum characteristics:The interaction of bitter receptor and ligand was the basis, intracellular calcium oscillation provides the insertion point for stochastic resonance theory analysis, and cell impedance spectrum characteristic was noise source of excitation signal frequency disturbance and the auxiliary means of weak signal extraction.