Protein And Cell Impedance Sensing Study Based On Microelectrode Chips

In the field of biosensors, electrochemical impedance spectrum (EIS) detection technology is one widely used transducer technology due to its low-cost, on-line, nondestructive, high throughput characteristic. This research aimed at the study of a protein based-biosensor and a cell based-biosensor both using EIS as transducer technology. Because of the high sensitivity and signal-to-noise ratio, microelectrode chip was chosen to accomplish EIS detection.A novel olfactory biosensor was developed based on chemosensory proteins (CSPs) of Chinese honeybee, Apis cerana cerana. The availability of large amount of recombinant CSPs has overcome the difficulty to obtain biology sensing material and to manufacture biosensor. By recording the impedance spectroscopy, specific pheromones and floral odors, including isoamyl acetate, geraniol, phenylacetaldehyde, produced detectable and linear electron transfer resistance variation with increasing concentration, with a detection limit of micromole. With the aid of molecular modeling, we attained the detailed information of ligand-protein interaction. It was proved that conserved residues would determine the ligand binding specificity of proteins. Then through molecular modeling, we established the correlations between protein-ligand binding characteristics and impedance spectra change.Cell sensor was designed to study the cytotoxicity of chemotherapy drugs to colon adenocarcinoma cell, LS180. The experimental results showed the cytotoxicity of oxaliplatin and5-fluorouracil was time-, concentration-dependent. The combination regimen of oxaliplatin and5-fluorouracil was more effective than single-agent. Additionally, two kind of Chinese herbal medicines, including Aidi injection and compound sopharo flavescens injection, have been proven to be good anti-cancer drugs simultaneously. These results would be very helpful for the development of new chemotherapy drugs and new regimens. With cell-electrode impedance model we could reproduce the change of cell morphology. It is helpful to study the mechanism of drug anti-cancer. Combining computer modeling techniques and sensing techniques could reduce the cost of experiment and extend theoretical research. Computer modeling techniques have been significant for researches on proteins and cells detecting.