Healthy cells look like this.
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These are cells exposed to 1 second of 561nm light every 5 minutes. The total movie is about 3h. The cells retract, detach and eventually die.
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This is another example of cells exposed to 1 second of 405nm and 1s of 561nm light every 5 minutes. The total duration is about 8h.
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If you step back then you can see that the damaged are actually limited to the exposed area
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Cells were imaged for 100ms with 561nm light every 5 minutes. Cells are dividing faster than the effect of photo-toxicity that is occurring. Again here the best way to control is to take an overview image at the end of the acquisition and compare exposed cells to non-exposed cells.
Click on the image to see the movie