Experimental Studies Of Piezoelectric Quartz Crystal Coagulation-Assay Sensor And Micro-array Immunosensor

Objectives:To establish detection platform for piezoelectric quartz crystal oscillation frequency and to investigate the influential factors in the determination with piezoelectric quartz crystal sensor in liquid phase so as to construct piezoelectric quartz crystal coagulation-assay sensor and micro-array immunosensor. Besides, the possibility of applications in clinical laboratory was also explored.Methods:1. Technology of fine processing was used to make single quartz crystal wafer and then the gold electrode around two sides of the sensor was plated. Different thickness and diameters of the gold electrodes were compared in order to determine the impact on coagulation assay and the detection of immunosensor. Based on the Glue-type 2 X 5 Model of micro-array sensor, Clamp-type 2 X 5 Model of micro-array sensor was constructed accordingly. Also self-oscillating TTL circuit and self-made and optimized PESA version 2.0 software applied to record and analyze frequency were developed. Then the universal detection platform for oscillation frequency of piezoelectric quartz crystal micro-array sensor was constructed by logically integrating all above the components, the computer, the temperature control, shockproof and shield apparatuses.2. The effects of density, viscosity, ion concentration, pH value, volume, temperature and repeatedly added solutions on oscillation frequency of quartz crystal were investigated, respectively. The optimal detection system and conditions were determined to eliminate or decrease the influence ofnonspecific biological reactions.3. The rule of the changes of oscillation frequency of piezoelectric quartz crystal was investigated in plasma coagulation reaction in order to establish the judgement standard of the start and the end points in the course of plasma coagulation reaction and the detection methods of prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT) by piezoelectric quartz crystal sensor. Then, comparison analysis was carried out to determine the possibility of clinical application.4. Anti-insulin antibody was immobilized on the gold electrode surface of piezoelectric quartz crystal immunosensor. The amount, consistency, biological reaction activity of immobilized antibody and response characteristics, regeneration ability of constructed piezoelectric quartz crystal insulin immunosensor were also compared respectively to determine the best method for antibody immobilization of piezoelectric quartz crystal immunosensor.5. Based on 2X5 Model of Clamp micro-array sensor, piezoelectric quartz crystal AFP-CEA-PSA-hCG tumor markers micro-array immunosensor was designed and fabricated successfully. The optimal detection conditions such as detection time, temperature were determined and the detection standard curves were also established respectively. Then, sensitivity, detection limit, nonspecific response, regeneration ability of piezoelectric quartz crystal micro-array immunosensor were observed. At last, clinical samples were detected with it and the results were compared with those detected with conventional labelling immunoassay in order to explore the possibility of detecting clinical samples.6. The piezoelectric quartz crystal insulin-C peptide micro-array immunosensor was constructed and the response characteristics of the immunosensor were observed. Clinical samples were detected with it and the possibility of detecting the biomolecule with light molecular weight in plasma samples was explored.Results:1. 10MHz AT-cut quartz crystal with gold-coated electrodes of 4.0 mm in diameter and 100 -150 nm in thickness was found to be of less insertion loss, strong vibromotive ability and stable oscillation in liquid phase, high sensitivity and heavy quality load, which would be the most suitable for plasma coagulation analysis and binding assay of antibody with antigen. The Clamp micro-array sen...