Home > News > Detecting Radical Damage in Cells
Detecting Radical Damage in Cells
Posted on 13/10/2008Detecting radicals in cells is a challenge because of the short lifetime of most of the free radicals involved. Centre scientists are working to overcome this by creating special dye molecules that emit light when exposed to radicals.
These new additives may act both as free radical detectors and as protective antioxidants. Centre researchers at the Queensland University of Technology and the Heart Research Institute are investigating oxidative stress in biological systems using fluorescence microscopy. They have devised a way to visualise radicals by incorporating nitroxide radicals into fluorescent probes. The nitroxide acts as a "short-circuit" that "turns off" light emission (fluorescence) whilst the nitroxide is intact. However when the nitroxide reacts with a radical the probe emits fluorescent light. Thus, cells that contain the probe exhibit a low background level of light emission until they are challenged with radicals – as the nitroxide reacts with the radical the short-circuit is destroyed and light is emitted.
The effect is reversible and so for the first time this technique allows researchers to follow the oxidative status of a cell as it grows and deals with oxidative stress. The researchers have also been able to control where the new probes go within the cells by varying the chemical structure of the probes as can be seen in the accompanying pictures. The green (fluoresein-based) probes localise in the cell membrane whereas the red (rhodamine-based) probes are localised in other sub-cellular compartments.
The effect is reversible and so for the first time this technique allows researchers to follow the oxidative status of a cell as it grows and deals with oxidative stress. The researchers have also been able to control where the new probes go within the cells by varying the chemical structure of the probes as can be seen in the accompanying pictures. The green (fluoresein-based) probes localise in the cell membrane whereas the red (rhodamine-based) probes are localised in other sub-cellular compartments.
Using these new probes Centre researchers have examined cell populations and can now pick out those subject to oxidative stress and those which are not. The double peak compared to the single peak from healthy cells shown in the right hand panel indicates the two populations of health and stressed cells.
By combining the powerful techniques of confocal and fluorescence microscopy with flow cytometry researchers in the Centre are now setting out to explore the role of antioxidants in various disease states. These powerful new tools provide the opportunity to screen new drugs which may modulate radical formation and damage in disease.