Once a source of blue light has been established, the next step to screen materials for
blue light-induced ROS would be to decide the
means of measuring ROS. Since mitochondria
are one of the prime targets for blue light, a
good place to start would be an ROS indicator
specific to mitochondria.
Commercially available fluorescent indicators are readily available, such as mitoSOX.
Besides preferentially accumulating in the mitochondria, mitoSOX also selectively interacts
with one of the main ROS species formed by
blue light: superoxide. Alternatively, mitochon-
MitoPY1. Again, this indicator preferentially
accumulates in the mitochondria; however it is
specific for H2O2, which is another ROS generated by blue light irradiation.
With respect to both mitochondrial ROS
indicators, not only can fluorescence intensity
be quantitatively measured using a fluorometer,
to determine if an active is effective at reducing
ROS, but they also can be visualized with fluorescence microscopy for presentation purposes.
The sensitivity of mitochondria to blue
light irradiation cannot be understated. Since
they are more susceptible to blue light damage
than the cell nucleus, the DNA damage associated with blue light-induced ROS production
appears to occur preferentially in mitochondrial
It is important to make sure that the
actives found to protect against blue light
do not interfere with its beneficial aspects.
There are ways to specifically measure mitochondrial DNA damage using quantitative PCR as well as fluorescent dye indicators.
Vol. 133, No. 2 | February 2018 Cosmetics & Toiletries® | 43