Optical techniques examine toxic agents in cells

Dec 09, 2013
Optical techniques examine toxic agents in cells
Credit: EPFL

EPFL researchers have developed a method for accurately determining the toxicity of nanomaterials. By using optical techniques, they are able to measure the concentration of the oxidizing substances produced by a damaged cell. Furthermore, this research also offers a new way to know more about the mechanisms of oxidative stress.

Nanopowders, nanocrystals, nanofibers, nanocomposites ... Today we can find nanomaterials everywhere; in the products we consume and in our daily environments. In order to accurately determine their toxicity, EPFL researchers have developed an for measuring the oxidative stress that some of them provoke on cells. They used , such as measuring the light absorbed by certain proteins. This research is being published today in Nature's Scientific Reports.

When a cell is exposed to a toxic product or a pathogen, this causes the internal equilibrium between the oxidants and antioxidants within the cell to break. Then the former, generally oxygen derivatives, are produced in excessive quantities and start to attack the cell's proteins, sugars and its membrane. This brings about a faster cellular aging, causes certain diseases to the cell, and may even lead to its death.

Thus, the overproduction of such oxidants is a sign that the cell is stressed, and that is exactly what researchers wanted to measure. At the same time, they noticed that cytochrome c, a protein present in the cellular membrane, was a particularly interesting biosensor. They found that when it was exposed to certain wavelengths of light, this protein would absorb less light when in the presence of one of these oxidizing agents: hydrogen peroxide. Consequently, they developed a complex method for measuring the variations of light absorbed by cytochrome c. Finally, they tested and verified their method on small unicellular algae.

More or less harmful depending on the environment

To this day there were no truly reliable methods for measuring continuously and without damaging the cells. This new test has opened interesting possibilities for identifying not only the effect of , but also, on a wider perspective, the way cells react to an external perturbation. In addition, during their experiments researchers were able to observe that the toxicity of certain products could be conditioned and modulated by its surrounding environment. For example; a nanomaterial may be less dangerous under a laboratory microscope than within a river's waters.

"The test that we propose is highly sensitive and able to indicate the concentration of oxygen derivatives in a thorough and detailed way, said Olivier Martin, director of the Nanophotonics and Metrology Laboratory (NAM). Since it is based in assessing a substance released outside the , it is also non-invasive. Therefore, it does not destroy the living organism and can be applied over a period of several hours making it possible to observe the evolution of the situation over time." Tests continue to be made on different types of materials

Explore further: Scientists use nanoparticles to shut down mechanism that drives cancer growth

More information: "Sensing the dynamics of oxidative stress using enhanced absorption in protein-loaded random media", Guillaume Suarez, Christian Santschi, Vera I. Slaveykova, Olivier Martin. Scientific Reports.

Related Stories

A protein's life, up close and personal

Jan 07, 2013

(Phys.org)—An EPFL team has developed a technique for spying on the inner lives of cells. For the first time, scientists have used a near-infrared, light-sensitive biocompatible molecule to mark and observe the activity ...

Biosensor for measuring stress in cells

May 16, 2008

Cancer, nervous system disorders such as Parkinson’s disease, cardiovascular disorders and old age have one thing in common: Both in afflicted tissue and in aging cells, scientists have observed oxidative changes in important ...

Oxidative stress: Less harmful than suspected?

Dec 05, 2011

Arterial calcification and coronary heart disease, neurodegenerative diseases such as Parkinson's and Alzheimer's, cancer and even the aging process itself are suspected to be partially caused or accelerated ...

The right dose for oncology

Mar 04, 2013

EPFL researchers develop a tool for oncologists using the electrical signature of cancer cells to get just the right treatment dosage for each patient.

Recommended for you

A stretchy mesh heater for sore muscles

Jul 03, 2015

If you suffer from chronic muscle pain a doctor will likely recommend for you to apply heat to the injury. But how do you effectively wrap that heat around a joint? Korean Scientists at the Center for Nanoparticle ...

Polymer mold makes perfect silicon nanostructures

Jul 03, 2015

Using molds to shape things is as old as humanity. In the Bronze Age, the copper-tin alloy was melted and cast into weapons in ceramic molds. Today, injection and extrusion molding shape hot liquids into ...

Better memory with faster lasers

Jul 02, 2015

DVDs and Blu-ray disks contain so-called phase-change materials that morph from one atomic state to another after being struck with pulses of laser light, with data "recorded" in those two atomic states. ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.