| The multi-channel series piezoelectric quartz crystal (MSPQC) is a bioelectrochemical device based on the series piezoelectric quartz crystal (SPQC) sensors response in aqueous solutions. It has sensitive response to the electric parameter changes (such as conductance and capacitance) between the electrodes. The MSPQC-based method is attractive due to its high sensitivity, broad sensing spectrum, low cost and easy operation. It has been widely used in a lot of areas, such as analytical chemistry, life science, clinical medicine, environmental monitoring etc. This dissertation, based on the study of our group, is devoted to the study of novel microorganism piezoelectric quartz crystal sensors. The new microbial sensing methods were presented base on the non-mass response of MSPQC sensor which related to some characteristics of microbial growth and metabolism. These new methods were simple, accurate and rapid, which have also broadened the application of MSPQC in environmental monitoring and life science. The main work of this thesis could be summarized as follows:1. A new medium based on MSPQC was proposed for rapid detection and quantification of Micrococcus luteus (M luteus). Proposed medium can effectively stimulate the growth of M. luteus and good response signal was obtained in MSPQC. Quantitative detection of M. luteus can be performed based on the fact that the frequency detection time (FDT) detected by MSPQC in developed new medium had a linear relationship with the logarithm of its initial concentration in the range of 10-107 colony forming units (cfu)/ml (R=-0.9976). The detection limit was low to 10cfu/ml. A total of 59 clinical M. luteus isolates were also evaluated by proposed method and the accuracy rate was about 93.2%. Comparing with conventional method, proposed method is simple, rapid and easy to operate.2. A new maltose medium was proposed by improving the YC broth of our laboratory. The new medium can not only be used for rapid detection of Pseudomonas putida (P. putida) but also for identification of P. putida from Pseudomonas sp. strain. The proposed medium can effectively stimulate the growth of P. putida and its response signal in MSPQC was distinctive, which can be used to differentiate from other strains in Pseudomonas. So simply by the proposed medium can achieve the aim of rapid detedction and identification of P. putida. 3. A new interdigital electrode-series piezoelectric quartz crystal (IDE-SPQC) sensor for rapid detection of vesicular stomatitis virus (VSV) was proposed. Thiolated chitosans were synthesized and then modified on the surface of IDE. Then the modified IDE was used to adsorb HEP-2 cells, which were the sensitive cells of VSV. With the presence of VSV, HEP-2 cells will die and fall from the surface of the IDE, which will cause obvious resistance change of IDE. This change can be sensitively monitored by SPQC and so the purpose of rapid detection of VSV can be realized. The detection range was 1×103-1×106 cells/ml and the detection limit was low to 500 cells/ml.
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