Small Molecules And Nucleic Acids, Proteins Role In The Process Of A Piezoelectric Sensor Research

Piezoelectric bulk acoustic wave sensors, known as very potential sensing devices, have many advantages, such as high sensitivity, broad sensing spectrum, simplicity and convenient et al. In the present thesis, the piezoelectric sensing techniques were applied to the study in the fields of bioanalytical and biomedical chemistry, actually to the study of the physical and chemical processes of DNA and proteins at the solid-liquid interface and their interaction with micromotecuie. A series of creative and important results were obtained. The main work of the thesis could be summarized as follows.1. A novel process analysis method, with a piezoelectric quartz crystal impedance technique based on the mass effect, for real-time monitoring the activated Bleomycin-induced cleavage of DNA process was proposed. The DNA-coated piezoelectric sensor was in contact with Bleomycin solution at the existence of H2O2 and Fe3+. The optimized experimental condition was determined through the experiments about the effect of pH, ion strength, Bleomycin concentration and Fe3+ concentration. And then the results about other antibiotics, Cefradine, Streptomycin, Benzylpenicillin, Doxycycline, acetylspiramycin, showed that these antibiotics did not show the same behavior like Bleomycin.2. Kinetics Studies of the interaction between antkumor antibiotics, Mitomycin and Bleomycin, and DNA was made with a novel process analysis method, piezoelectric quartz crystal impedance analysis. The experimental results indicated that antitumor antibiotics concentration had an effect on the interaction. A pseudo-first-order kinetic model for the interaction between antitumor antibiotics and DNA was derived to describe the process. By fitting experimental data to the model, the kinetic parameters were determined respectively. At the 37 0.5 , the kMMC and kBLM value obtained were 4.56 ( 0.02) 10-3 (mM)-1 s-1 and 9.11 ( 0.02) (mM)-1s-1 respectively.3. Real-time monitoring the interaction of L-tetrahydropalmatine (L-THP) and human serum albumin (HSA) was performed with a quartz crystal microbalance impedance technique. HSA was modified onto the surface of Au electrode by 3-step scheme. The optimized experimental condition was determined through theexperiments about the effect of pH, ion strength and L-THP concentration. The experimental data of frequency shift at different temperatures were fitted to the derived model and kinetics parameters, k , f0,max and qr, were obtained respectively. According to Arrhenius formula, activation energy (19.57 kJ-mol" ) was also gained.4. The adsorption of human serum albumin onto hydroxyapatite-modified silver electrodes has been in situ investigated by using the piezoelectric quartz crystal impedance technique. The changes of equivalent circuit parameters were used to interpret the adsorption process. A kinetic model of two consecutive steps was derived to describe the process and compared with a first-degree kinetic model by using residual analysis. The experimental data of frequency shift fitted to the model and kinetics parameters, k1, k2, 1, 2 and qr, were obtained. According to Arrhenius formula, two adsorption steps activation energy (7.19 kJ-mol-1 and 22.89 kJ-mol-1) were obtained.