Visualization and Tracking of Nanostructures in Aqueous Environments

Visualization of Morphological Change of Telescoping MWNTs with Quantum Dots

Functionalized quantum dots (QDs) have been successfully attached to double-walled and multi-walled carbon nanotubes (DWNTs and MWNTs). Characterization in a transmission electron microscope (TEM) shows the QDs are attached mostly at the opened tips and defect sites on the sidewalls of nanotubes, suggesting the covalent nature of the bonding and high selectivity to chemically reactive sites. Due to their unique fluorescent properties, the visibility of the nanometer-sized QDs (a few nm thick) under an optical microscope creates the possibility of tracking the motion or morphology change of individual decorated nanotubes in a liquid environment and identifying possible sites for covalent attachment. This enables the integration of carbon nanotubes with biomolecules such as biomolecular motors, for building bio-nanoelectromechanical systems (BioNEMS).

Figure 01: Theoretical illustration of a telescoping multi-walled carbon nanotube with quantum dots attached in order to track morphological changes.

Figure 02: TEM image of multi-walled carbon nanotube with quantum dots (~ 5.2 nm crystal diameter) attached to its tip.

Figure 03:TEM image of multi-walled carbon nanotube with quantum dots (~ 5.2 nm crystal diameter) attached to its wall.

Figure 04: CLSM image of multi-walled carbon nanotubes fluorescent with quantum dots.

D. R. Frutiger, L. Dong, B. J. Nelson, "Optical Tracking of Multi-walled Carbon Nanotubes by Attaching Functionalized Quantum Dots", Proc. 2006 IEEE Int. Conf. on Nano/Micro Engineered and Molecular Systems, Zhuhai, China, January 2006.