Nanotube Sensors Detect Toxins in Cells

This image shows the cell before hydrogen peroxide is added. Image courtesy of Strano Laboratory

After hydrogen peroxide is added to the cell, the change in fluorescence enables different molecules to be identified. Image courtesy of Strano Laboratory

Engineers at MIT have developed carbon nanotube-based sensors that could be used to verify the efficacy of chemotherapeutics in cancer treatment. “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,” says Michael Strano, associate professor of chemical engineering. The sensors could be used to verify that chemotherapeutic agents, which can cause serious side effects, are targetting a tumor and not healthy tissue. “You could figure out not only where the drugs are, but whether a drug is active or not,” adds Daniel Heller, an MIT graduate student in chemical engineering.

The sensor can detect DNA-alkylating agents, a class that includes cisplatin, and oxidizing agents such as hydrogen peroxide and hydroxyl radicals.

Using the sensors, researchers can monitor living cells over an extended period of time. The sensor can pinpoint the location of molecules inside cells, and for one agent, hydrogen peroxide, it can detect a single molecule.

“We can differentiate between different types of molecules depending on how they interact,” Strano explains.

Each nanotube is coated with DNA, which binds to DNA-damaging agents in the cell. That interaction between the DNA and DNA disruptor changes the intensity or the wavelength of the fluorescent light emitted by the nanotube. The agents produce different signatures that can be used to identify them. Carbon nanotubes fluoresce in near-infrared light while human tissue does not, making it easier to see the nanotubes light up.

The nanotube sensors are safe for injection in living cells.

More information on this research is available from the MIT News Office.

Tags: cancer, chemotherapy, DNA, Michael Strano, MIT, nanotube