Cell-based Biosensing Study Using Piezoelectric And Electrochemical Technique

Cell is the basic structural and functional unit of all organisms. Cell research is one of essential links revealing life mystery and conquering desease. The deep awareness of cellular physiological processes can be achieved by exploring morphological change, function change and biochemical change in surroundings of cells. It may promote the progress of life science, biomedicine, analysis technique and materials science. Investigations on cytotoxicity of nanoparticles, cell detection based on molecular recognition and cell agglutination process for in-vitro cultured cells by electrochemical methods and piezoelectric sensing technique in the thesis are given. The main work is summarized as follows:1. The individual and combined cytotoxicity of 5-fluorouracil and the three nanoparticles, silica, selenium and gold nanoparticles against human osteosarcoma MG-63 cells were investigated by using cyclic voltammetry and microscopic observation, respectively. It is found that both the drug and the nanoparticles were able to inhibit cell proliferation in a dose-dependent way and the inhibition efficiency of Au NPs was most prominent. The combination of 5-FU with high-concentration SiO2 NPs and Se NPs presented a simple-addition and synergistic effect, respectively. The present work may be conducive for the exploration of the applications of nanoparticles in biomedicine and cancer treatment.2. Mouse anti-human integrinβ1 monoclonal antibody was assembled on glass carbon electrode by layer-by-layer adsorption. The determination of cervical cancer HeLa cells was performed using electrochemical impedance spectroscopy based on the immunoreaction between integrinβ1 on cell membrane and the antibody immobilized on the electrode-surface. The factors influencing cell-detection, such as the concentration of gold nanoparticles in the modified film, the drying time of the modified film, the concentration of antibody and the binding time of antibody, were investigated, respectively. Under optimum conditions, the increasing extent of electrode-transfer resistance depended linearly on the cell concentration in the range of 1.0×104-2.0×106 cells mL-1 with a detection limit of 3.5×103 cells mL-1.3. The real-time monitoring of the agglutination process of human hepatic normal cells (L-02) at the quartz crystal microbalance (QCM) gold (Au) electrode was performed. Two lectins, concanavalin A (Con A) and wheat germ agglutinin (WGA), induced the cell agglutination, resulting in the different△f0 and△R1 responses from those caused by the normal cell attachment and growth. The cell-Con A-cell aggregates had higher affinity for the Au substrate due to the excellent adsorption ability of Con A, which was revealed by increased△f0 and shifts and the obvious mass effect of QCM. In contrast, the lower adsorption ability of cell-WGA-cell aggregates was related to the same characteristic of WGA, presenting the decreased△fo and△R1 responses and the time-extended adhesion phase. Parallel microscopic observation experiments were also carried out and exhibited comparable results. The△f0 responses during the processes of cell growth and cell agglutination were analyzed using the equations△f0=a0+a1e(?)/τ1+a2e(?)/τ2+a3e(?)/τ3 and△f0=a0+a1e(?)/τ1+a2e(?)/τ2, respectively. Furthermore, the current work proved that the QCM measurement technique based on cell agglutination was useful for discriminating hepatic normal cells (L-02) and hepatic cancer cells (Bel7402).