(Nanowerk News) Biomedical researchers at the University of Arkansas and University of Arkansas for Medical Sciences in Little Rock have developed a special contrast-imaging agent that is capable of molecular mapping of lymphatic endothelial cells and detecting cancer metastasis in sentinel lymph nodes. The new material could be used as a more efficient and less toxic alternative to nanoparticles and fluorescent labels used in the non-invasive, targeted molecular detection of normal cells, such as immune-related cells, and abnormal cells, such as cancer cells and bacteria. Findings were published Sunday in Nature Nanotechnology.
Developed by Zharov, photoacoustic and photothermal methods deliver energy, via laser pulses, into biological tissue. When some of the energy is absorbed and converted into heat, it expands and emits sound waves. However, the carbon nanotubes had not been fully developed as an imaging agent because of concerns about toxicity.
Kim’s research team addressed this problem by depositing a thin layer of gold around the carbon nanotubes. The gold layer enhanced absorption of laser radiation and reduced toxicity. In vitro tests showed only minimal toxicity associated with the golden nanotubes. Compared to existing nanoparticles, the golden nanotubes also exhibited high laser absorption at a miniscule diameter. The golden nanotubes required extremely low laser-energy levels for detection, and low concentrations were required for effective diagnostic and therapeutic applications.