Carbon nanotubes are fast becoming one of the ubiquitous technology components of the twenty-first century, much as plastics and silicon were in the last. From electronics, to building materials, to medicine, no challenge seem above the amazing carbon molecules, whose properties read like a materials engineer's wish list.
The latest application may be to use nanotubes as tiny sensors to detect whether chemical agents pertinent to the study of cancer were present and whether they were active. Researchers at MIT wrapped nanotubes in special segments of DNA and were able to successfully detect the quantity and status of chemotherapy drugs, toxins, and free radicals. The common drug cisplatin was among the chemotherapy agents detected.
Michael Strano, associate professor of chemical engineering and one of the study's leaders describes, "We've made a sensor that can be placed in living cells, healthy or malignant, and actually detect several different classes of molecules that damage DNA."
The new sensor could play a critical role in evaluating the success of chemotherapy treatments. As most chemotherapy agents act as DNA disruptors, and can harm living cells, it is critical to see if they are successfully reaching their targets -- cancer cells, and how much is accumulating in healthy cells. Daniel Heller, a graduate student in chemical engineering, also a leader of the project, describes, "You could figure out not only where the drugs are, but whether a drug is active or not."
The new sensor detects DNA-alkylating agents, a class of molecules that both cancer-causing free radicals and some cancer-fighting chemotherapy drugs fall under. Hydrogen peroxide and hydroxyl radicals were two of the toxins detected by the sensors. For hydrogen peroxide, the sensor could detect single molecules of the chemical.
When exposed to fluorescent light, the nanotubes, which congregate around their targets, light up, while human tissue does not. The nanotubes bind to their target via bonding between the DNA coating and the DNA disruptors. When exposed to light, depending on the agent bound to the DNA, different wavelengths of light are emitted, allowing the particular compound attached to be determined.
The nanotubes are human-safe as they are coated in DNA, which protects living cells from harmful effects of nanotubes.
The research is reported in this month's issue of the journal Nature Nanotechnology.
The researchers plan to next test the effectiveness of more chemotherapy drugs using the sensors, and also to test the cancer-fighting effectiveness of popular antioxidants such as chemicals found in green tea.
The research is funded by grants from the National Science Foundation (NSF).
quote: Carbon nanotubes are fast becoming one of the ubiquitous technology components of the twenty-first century, much as plastics and silicon were in the last.