Carbon Nanotube-based Chemo/biosensing And Construction Of Cell-based Biosensing Interface

Since their discovery in 1991, carbon nanotubes have been found great applications in many fields including physics, chemistry and material science, due to their unique one dimensional tubular structure, unusual mechanical, electrical and electrochemical properties. On the other hand, in vitro assays using cultured cells are of great significance for studying many aspects of cell biology and drug screening. The construction of cytocompatible interface plays an important role for the fabrication of cell-based biosensors, and could undoubtedly promote the development of tissue engineering. In this thesis, a series of studies on carbon nanotube-based chemo/biosensing and construction of cell-based sensing interface were carried out, and some valuable results were obtained. The main points of this thesis are summarized as follows:1. Based on the interaction between amino groups on DNA bases and carboxylic acid groups on multi-walled carbon nanotubes (MWNTs), calf thymus DNA was covalently attached to MWNTs. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the immobilization. Interaction between the immobilized double-stranded DNA and ethidium bromide was observed obviously by CV and EIS analysis, indicating that the DNA molecules immobilized at the surface of MWNTs, with little structure change, still has the ability to interact with small biomolecules.2. Based on electrostatic interaction, calf thymus DNA was self-assembled on MWNTs-modified gold electrode via a cationic polyelectrolyte. Piezoelectric quartz crystal impedance technique was employed to monitor the assembly of DNA in real time. EIS was also used to characterize the modification process. The immobilized DNA could interact with chlorpromazine hydrochloride. This implies that DNA assembled on MWNTs still has the ability to interact with drug molecules, which has great importance in the construction of new types of miniature DNA biosensors.3. A carbon nanotube-based amperometric cholesterol biosensor was fabricated through layer-by-layer deposition of a cationic polyelectrolyte and cholesterol oxidase on MWNTs-modified electrode. EIS was used to characterize the assembly process. To improve the anti-interferent ability, a non-conducting film was electrochemically formed on the enzyme electrode. The presence of...