Studies On The Applications Of Carbon Nanotubes In Drug Delivery And Analytical Detection Of Biological Macromolecules

Since the discovery of carbon nanotubes (CNTs) by a Japanese scientist-Sumio Iijima in 1991, CNTs have been considered as one of the most potential novel biomedical materials. Due to the high aspect ratio, easy functional modification, supportive substrates, favorable biocompatibility, low toxicity to biological systems, and distinct optical properties of CNTs, they have found wide applications in fields such as delivery of drugs, biophysical treatments, matrices and stimulators for neuronal growth, and biosensors of protein, DNA and atomic mass up to now. In this thesis, with the aids of optical properties and high affinity with DNA, drug as well as cytomembrane, multi-walled carbon nanotubes (MWCNTs) were employed to the specific detection of virus DNA, the delivery of antibiotic and enrichment of microbe. The main content is as follows:(1) Build a novel MWCNTs-based drug delivery system, in which, nutrient broth treated multi-walled carbon nanotubes (NBT-MWCNTs) and cefotaxime sodium (CTX) were employed as a model. Through overall investigation of dispersion effect, biocompatibility, pharmacodynamic effect and delivery efficiency, it was found that MWCNTs can be well dispersed in the nutrient broth and stable for at least one week at 4℃. Compared with general acid treated MWCNTs (AT-MWCNTs), the present drug delivery system shows good biocompatibility, enhanced pharmacodynamic effect, and high delivery efficiency. Moreover, the function that MWCNTs protect drug from enzymatic cleavage was employed to investigate the antibacterial activity of pazufloxacin and reversion of bacterial drug resistance. This method provides a novel routine to clinic treatment of drug-resistance bacterial infection and reversion of bacterial drug resistance.(2) Put forward a novel visual analytical method of DNA. In this method, the light scattering (LS) of MWCNTs and paramagnetism of magnetic particles (MNPs) were employed to detect hepatitis C virus (HCV) DNA. The probe DNA was first modified on the MNPs via covalent coupling, then with the addition of target DNA, double-strand DNA (dsDNA) formed by the hybridization of probe DNA and target DNA can't adsorb on MWCNTs, demonstrating strong LS signals after separation by an external magnet. Based on the significant difference, a novel method for HCV DNA detection has been proposed with good specificity, high sensitivity.(3) Prepare a novel MWCNTs-based microorganism hunter. ssDNA was first modified on the silanized capillary by glutaral and then MWCNTs were immobilized throughπ-πinteraction between DNA bases and MWCNTs, producing a "nano-fish pole" device. Due to the high affinity between MWCNTs and cytomembrane, the device exhibited ability to actively hunt and capture the bacteria in aqueous solutions. It was found that the capture process is fast, sensitive and effective in solution phase, which could further applied to the analysis of water sample.