| Along with economic development and human progress, people now tend to seek a more virtuous cycle of sustainable lifestyle. The issues on environmental improvement, food security and healthcare have aroused the extensive social concern. In the meanwhile, the scientific research derived from these regions has put forward higher requirements for fast, intelligent and non-invasive detection. Towards these requirements, electronic tongue (E-Tongue) shows its advantages of fast and simultaneous measurement, with more portable and convenient setup but lower power consumption. Therefore, it leads extensive applications in environmental monitoring, food and pharmaceutical industries.This dissertation mainly discusses about the research on two types of potentiometric electronic tongue, namely light-addressable potentiometric sensor (LAPS) and ion-selective electrode (ISE), and electric cell-substrate impedance sensor, as well as their application on heavy metals detection and pharmaceutical evaluation. On the basis of semiconductor physics, a novel structured LAPS array based on PVC-membrane and chalcogende galss membrane was proposed and fabricated for the detection of heavy metals. This was considered to realize the internal multisensor system for detection of multiple parameters. Regarding to realization of the integration of different types of sensors, two kinds of integrated sensor chip with combination of LAPS and micro electrode array (MEA), LAPS and nanoband electrode array (NEA) respectively, were also designed multisensors for water-environmental monitoring in a wireless sensor network. In order to evaluate the pharmaceutical bitterness and bitter masking effect, ion-selective electrodes (ISEs) were firstly selected from a view of sensitive and multiselective mechanism. Then they were utilized in assessment of traditional Chinese medicine (TCM) and western medine. Based on electric cell-substrate impedance sensing (ECIS) system, drug effect of TCM on cell-proliferation promotion has been investigated. The research work in this dissertation was under the support by the National High Technology Research Program (863Program), the National Key Basic Research Program (973Program) and National Research FoundationThe major contribution and innovation of this study is listed below:1. A PVC membrane based LAPS was proposed fabricated for the detection of heavy metals in water environment.PVC membrane containing the respective sensitive ionophores was prepared on LAPS for detection of Zn2+, Cd2+, Pb2+, Cu2+. The morphology and surface characteristics were investigated. The electrochemical characterization of the fabricated sensor was investigated by means of sensitivity, selectivity, response time, stability and detection limit. Meanwhile, the role of silanization and supporting electrolyte was evaluated.2. A novel structured LAPS array based on PVC-membrane and chalcogende galss membrane was fabricated. Through this new structure, the problem of cross-talk was largely inhibited. Consequently, the calibration stability of sensor array was enhanced and the response time was shortened.In the fabrication of the sensor chip, part of silicon substrate which was defined as non-sensitive area was heavily doped with boron and had thick oxide formation. Through this new structure, the elaborated LAPS had the advantages of low cross-talk, excellent calibration stability and shorter response time.Sensors based on PVC membranes and chalcogenide glass membranes showed a sensitivity of28-30mV/dec for the respective cations and response time of3-10s, over the concentration ranges of10-5to10-1M. The detection limit was around10-6M.3. A methodology of calibrating the LAPS sensor in the buffer system of heavy meatals was proposed. Results showed that under the circumstance of buffer solutions, the detection limit of sensor could be at ultra-low level.LAPS array was calibrated in buffer solution for detection of ultra-low cactivity of heavy metals. The buffer solution was prepared using heavy metal ions, ligands, pH buffer and supporting electrolyte. The sensor slopes in buffers were29.7and29.3mV/decade respectively for Cd2+and Pb2+of concentrations ranging from10-6M to less than10-18M. The linear segments of the response curves in buffer solutions were essentially collinear with the potentiometric response in unbuffered nitrate standards that yielded the typical slope (around29mV/dec) in the range of10-5-10-1M. The detection limit of sensor could be largely lowered and extended to pico-molar level.4. Micro-nano opto-eletronic integrated sensor chip was further designed and studied. The self-calibration of this multsensor system was preliminarily realized.Micro-nano opto-eletronic integrated sensor chip was developed and studied for water-environmental monitoring. In this chip, MEAs of NEAs were integrated with LAPS on the same silicon substrate. Fluidic system and wireless sensor network were combined with the sensor while self calibration model was established based on multiple linear regression equation.5. Through the collaboration with Russian group, the methodology of bitterness evaluation of Pharmaceuticals using electronic tongue and drug effect assessment using cell-based biosensor was proposed.For the bitter taste assessment of western medicine, eight active pharmaceutical ingredients (APIs) and three blind samples were studied with the multisensor system. Through the model of PLS or3wayPLS regression model, the artificial assessment of bitter taste with ET in the chosen set of APIs is possible. PCA was used to analyse different substances, different concentrations and the masking effect by means of sweetness addition. Furthermore, ISEs system was firstly used for the bitter taste assessment of Chinese medicine. Cross validation (leave-one-out validation) was used to evaluate the predicting abilities of the constructed model. Based on electric cell-substrate impedance sensing (ECIS) system, drug effect of TCM on cell-proliferation promotion has been investigated. |
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