Nano-technology Breakthrough May Prevent Cancers from Metastasizing
With the goal of removing tumor cells from the bloodstream, a biomedical engineering team at the University of Arkansas for Medical Sciences (UAMS) in Little Rock has discovered a non-invasive way to identify cancer and to capture tumor cells in the bloodstream. This landmark discovery, could dramatically improve early cancer diagnosis and prevent deadly metastasis. It could also provide a framework for a new type of diagnostic test that could detect metastatic cancer from a blood sample.
Led by Vladimir Zharov, Ph.D., D.Sc., Director of the UAMS Phillips Classic Laser and Nanomedicine Laboratory, the scientific team injected a cocktail of golden carbon nanotubes and magnetic nanoparticles with a special biological coating into the bloodstream to target circulating tumor cells. This allows a magnet attached to the skin above peripheral blood vessels to capture tumor cells, especially so-called “rolling cells.” This team published its findings in the Nov. 15, 2009 edition of Nature Nanotechnology.
Magnetically collecting tumor cells from circulating blood could increase specificity and sensitivity up to 1,000 times compared to existing technology, contend the researchers. There are two ways to eliminate the captured tumor cells. One approach is to micro-surgically remove the tumor cells and the nanotubes which hold them, making the tumor cells available for further genetic analysis. The second approach would be non-invasive and would directly eradicate the tumor cells from circulating blood by the use of laser irradiation through the skin at a level safe for normal blood cells.
Jin-Woo Kim, Ph.D., a UA biomedical researcher and Assistant Professor for Biological and Agricultural Engineering, came up with the idea of applying thin deposits of gold on carbon nanotubes and their biological coatings. The gold layer enhances absorption of laser radiation by tumor cells, while reducing toxicity to normal tissue because the golden nanotubes require extremely low laser-energy levels for detection.
Kim and Zharov have jointly worked on cutting-edge nanotechnology diagnostic tools for some time. In August 2009, the same journal announced their discovery of a special contrast-imaging agent capable of molecular mapping of lymphatic endothelial cells and detecting cancer metastasis in sentinel lymph nodes. That material, which is made of carbon nanotubes and gold, could be used for non-invasive, targeted, molecular detection of normal, immune-related cells and abnormal cells, including cancers and bacteria.
In a previous study, Kim and Zharov also demonstrated that carbon nanotubes hold great promise as contrast agents for photoacoustic detection and photothermal killing of individual bacteria in blood system. Collectively, these new technologies and approaches could provide the basis for entirely new ways to search for cancer cells and other diseases, while also using specimen types other than tissue. – P. Kirk
Golden carbon nanotubes as multimodal photoacoustic and photothermal high-contrast molecular agents