Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New sensor array detects single molecules for the first time

08.03.2010
Carbon nanotube sensor detects hydrogen peroxide emanating from a single living cell

MIT chemical engineers have built a sensor array that, for the first time, can detect single molecules of hydrogen peroxide emanating from a single living cell.

Hydrogen peroxide has long been known to damage cells and their DNA, but scientists have recently uncovered evidence that points to a more beneficial role: it appears to act as a signaling molecule in a critical cell pathway that stimulates growth, among other functions.

When that pathway goes awry, cells can become cancerous, so understanding hydrogen peroxide's role could lead to new targets for potential cancer drugs, says Michael Strano, leader of the research team. Strano and his colleagues describe their new sensor array, which is made of carbon nanotubes, in the March 7 online edition of Nature Nanotechnology.

Strano's team used the array to study the flux of hydrogen peroxide that occurs when a common growth factor called EGF activates its target, a receptor known as EGFR, located on cell surfaces. For the first time, the team showed that hydrogen peroxide levels more than double when EGFR is activated.

EGF and other growth factors induce cells to grow or divide through a complex cascade of reactions inside the cell. It's still unclear exactly how hydrogen peroxide affects this process, but Strano speculates that it may somehow amplify the EGFR signal, reinforcing the message to the cell. Because hydrogen peroxide is a small molecule that doesn't diffuse far (about 200 nanometers), the signal would be limited to the cell where it was produced.

The team also found that in skin cancer cells, believed to have overactive EGFR activity, the hydrogen peroxide flux was 10 times greater than in normal cells. Because of that dramatic difference, Strano believes this technology could be useful in building diagnostic devices for some types of cancer.

"You could envision a small handheld device, for example, which your doctor could point at some tissue in a minimally invasive manner and tell if this pathway is corrupted," he says.

Strano points out that this is the first time an array of sensors with single-molecule specificity has ever been demonstrated. He and his colleagues derived mathematically that such an array can distinguish "near field" molecular generation from that which takes place far from the sensor surface. "Arrays of this type have the ability to distinguish, for example, if single molecules are coming from an enzyme located on the cell surface, or from deep within the cell," says Strano.

How they did it: The sensor consists of a film of carbon nanotubes embedded in collagen. Cells can grow on the collagen surface, and the collagen also attracts and traps hydrogen peroxide released by the cell. When the nanotubes come in contact with the trapped hydrogen peroxide, their fluorescence flickers. By counting the flickers, one can obtain an accurate count of the incident molecules.

Next steps: Researchers in Strano's lab plan to study different forms of the EGF receptor to better characterize the hydrogen peroxide flux and its role in cell signaling. They have already discovered that molecules of oxygen are consumed to generate the peroxide.

Strano's team is also working on carbon nanotube sensors for other molecules. The team has already successfully tested sensors for nitric oxide and ATP (the molecule that carries energy within a cell). "The list of biomolecules that we can now detect very specifically and selectively is growing rapidly," says Strano, who also points out that the ability to detect and count single molecules sets carbon nanotubes apart from many other nanosensor platforms.

Source: "Detection of single-molecule H2O2 signaling from epidermal growth factor receptor using fluorescent single-walled carbon nanotubes," Hong Jin, Daniel Heller, Marie Kalbacova, Jong-Ho Kim, Jingqing Zhang, Ardemis Boghossian, Narendra Maheshri, Michael Strano. Nature Nanotechnology, March 7.

Jennifer Hirsch | EurekAlert!
Further information:
http://www.mit.edu

More articles from Life Sciences:

nachricht Rutgers scientists discover 'Legos of life'
23.01.2018 | Rutgers University

nachricht Researchers identify a protein that keeps metastatic breast cancer cells dormant
23.01.2018 | Institute for Research in Biomedicine (IRB Barcelona)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Rutgers scientists discover 'Legos of life'

23.01.2018 | Life Sciences

Seabed mining could destroy ecosystems

23.01.2018 | Earth Sciences

Transportable laser

23.01.2018 | Physics and Astronomy

VideoLinks Science & Research
Overview of more VideoLinks >>>