FUNCTIONALIZED CARBON NANOTUBES FOR BIOLOGICAL APPLICATIONS

Carbon nanotubes with their unique pseudo-one-dimensional nanostructures and related electronic, optical, and mechanical properties have been attracting much attention for potential biological applications, such as biosensors, bio-delivery, bioimaging and so on. In this dissertation, recent studies and advances toward bioapplications of carbon nanotubes are critically reviewed, followed by detailed reports on my research projects concerning the use of carbon nanotubes as unique scaffolds for multivalent display of sugars and the relevant results from bio-evaluation of these novel nanomaterials. Single-walled (SWNTs) and multiple-walled carbon nanotubes (MWNTs) were functionalized with amine-derivatived monosaccharides (galactoses and mannoses) and their dendritic constructs. These sugar-functionalized carbon nanotubes were readily water-soluble and biocompatible, and the intrinsic properties of the nanotubes were largely preserved post-functionalization. The bio-evaluation of the functionalized carbon nanotubes included experiments with pathogenic Escherichia coli O157:H7, in which specific interactions of the galactose (or its dendritic construct)-functionalized SWNTs with the E. coli cells to result in significant cell agglutination were observed. Similarly, the mannose-functionalized SWNTs were found to bind effectively to Bacillus subtilis (commonly used simulant for Bacillus anthracies or anthrax) spores for the formation of large aggregates. Also interesting was the finding that there were unique carbohydrate-carbohydrate interactions between SWNT-bound monosaccharides. All of the results suggest that carbon nanotubes are indeed unique scaffolds for displaying multiple copies of sugars either individually or in pairs or quartets and that these unique nanomaterials offer valuable biologically significant functions