Bio-Rad eBook - 2019 - 16

Meet the Innovators...
eventually came to a floor that we could not get
through. We realized that we needed to improve the
black coatings in the instrument in several places,
and the coating on the glass elements of the lens.
All of the paints that we had tried had different
characteristics, but none of them really cut it. So,
we finally ended up with a unique black coating
that we applied to all of the exposed metal surfaces
inside the imager. The lens elements required a
specific black paint to be applied to their edges,
and we had a custom multilayer broadband AR
coating applied to all the glass elements to increase
transmission, especially in the IR.
What were some other challenges
in increasing sensitivity, for example,
in low-light performance?
Imaging sensitivity is really important in light-starved
applications like chemiluminescence western
blotting, typically far-red or NIR fluorescence
applications. The reason that our optical system
is so good at taking pictures in low light is that it's
flat-out optimized for it. It has a ridiculously low dark
current CCD. It has a very fast lens that's optimized
for just the spectral ranges that we're operating in.
It has a zoom stage that you can maximize for the
smallest sample. You can take a picture zoomed in
to just a small sample to use the entire image
sensor for just that area, or you can take a picture
of multiple blots at the same time if that's your
choice. We also use custom, high-power LEDs
for fluorescent illumination.
The sum of all the customization and design that
we did for the camera itself, lenses, filtration, and
illumination ended up being unique enough in terms
of its performance capabilities that we wrapped it
all up into a patent. l

16

Evan Thrush

Evan Thrush, PhD, Principal Optical Engineer,
Life Science Research, Bio-Rad Laboratories

What is your role at Bio-Rad?
I'm a Principal Optical Engineer in the Life Science
Group, working in the area of optics, and sensing,
and fluorescence. I'm a physicist, and I always
wanted to do something applying physics to life
sciences, and optical sensing bridges that gap.
Optics involves a lot of physics, and in life science,
there's a lot of optical measurements being done.
I'm impressed that it's a very multidisciplinary group
here. I work closely with the application-side people
-biologists and chemists-with experts working in
these areas for 15 - 20 years, and everybody gets
involved from day one of the project.
What	were	some	specific	goals	of	the	
ChemiDoc MP project?
We wanted to match the performance of laser
scanners and also be able to do chemiluminescent
imaging and gel imaging. We considered using
lasers, but we ended up using custom LEDs and
custom filters. If you filter an LED properly, it
behaves a lot like a laser, and LEDs are very reliable
Bio-Rad eBook - 2019

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