| The multi-channel series piezoelectric quartz crystal sensor (MSPQC) is designed based on the principle of series piezoelectric quartz crystal (SPQC). It has the ability of detection multi-samples at one time. It has many advantages, such as high sensitivity, easy operation, broad sensing spectrum, real-time and on-line measurement etc. It has been widely used in many areas, such as analytical chemistry, life science, clinical medicine and environmental monitoring etc. Based on the special response of MSPQC and several metabolism characteristics of the most commonly encountered bacteria in clinic, some new detection methods were presented in this thesis,such as technology of interdigital electrodes modified polyaniline/titanium dioxide and new solid medium technology. And these new methods had broadened their application in clinical medicine. These new methods for the detection and identification of the most frequent bacteria encountered in clinic were ease to operate,rapid and accurate. The main work could be summarized as follows:1. A new polyaniline/titanium dioxide piezoelectric quartz crystal (PANI/TiO2-PQC) system was proposed to detect ammonia. In this system, interdigital electrode coated with a Polyaniline/Titanium Dioxide composite film was used as probe (PANI/TiO2) in place of steel electrode in multi-channel series piezoelectric quartz crystal (MSPQC) system. The probe was directly connected to the piezoelectric detection system. PANI/TiO2 film can rapidly react with NH3, the detection limit was 1.2 ppm. In this paper, PANI film and PANI/TiO2 film separately reacting with NH3 and reacting with different concentrations NH3 were investigated. The results show PANI/TiO2 film was excellenter than PANI film .and it proved the point that PANI/TiO2 film and PANI film detected Klebsiella pneumoniae. So it demonstrated that the proposed method is rapid, accurate and easy operation .2. The polyaniline/titanium dioxide ammonia sensor was proposed to detect Klebsiella pneumoniae. In this system, the probe was directly connected to the piezoelectric detection system. PANI/TiO2 film can react with NH3 produced by the growth of bacteria in culture medium, which caused the film electrical properties change, so we can rapidly detect Klebsiella pneumoniae. Following, compared with series piezoelectric quartz crystal(SPQC) sensor, it is more sensitively. Two culture mediums were used as test culture mediums in our experiment. The results showed that all two culture medium can be used as test culture medium in proposed system, but in SPQC system, only YC broth can be used. At the same time, interdigital electrode coated with a polyaniline/titanium dioxide composite film for Klebsiella pneumoniae have more shorter detecting time than MSPQC for Klebsiella pneumoniae. So it demonstrated that the proposed method is rapid, accurate and easy operation and it could be popularized in clinical microbiology laboratories. So it demonstrated that the proposed method is rapid, accurate and easy operation and it could be popularized in clinical microbiology laboratories.3. A new multi-channel series piezoelectric quartz crystal (MSPQC) was developed for rapid detection of S. aureus. The sensor is fabricated by coating a thin nutrient gelatin medium film at the bottom of detetion chamber . the consumption of the nutrient by S. epidermidis during its growth and reproduction increase conductance. in turn decreasing the resonance frequency. The proposed sensor is used to detect S. epidermidis in the range of 3×103 to 2×107 cfu/ml. The proposed sensor shows little response to bacteria which cannot liquefy gelatin, eg. Escherichia coli, exhibiting a certain selectivity to gelatin-liquefying bacteria. so the MSPQC method is simple, rapid, sensitive and convenient to perform. it could be popularized in clinical microbiology laboratories. |
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