UCLA's low-cost, lightweight, rugged microscope utilizes
holograms instead of lenses (Image: Ozcan BioPhotonics Group at
UCLA/Biomedical Optics Express)
While financial contributions are certainly a great help to
health care practitioners in developing nations, one of the
things that they really need is rugged, portable,
low-cost medical equipment that is compatible with an
often-limited local infrastructure. Several such devices are
currently under development, such as a
battery-powered surgical lamp, a
salad-spinner-based centrifuge, and a
baby-warmer that utilizes wax. UCLA is now working on
another appropriate technology in the form of a small,
inexpensive microscope that uses holograms instead of lenses to
image what can't be seen by the human eye.
Currently in the prototype stage, the microscope fits in the
palm of the hand, and reportedly weighs "as much as a
medium-sized banana." It is made entirely from off-the-shelf
electronics, resulting in a total materials cost of just US$50
to $100 per unit. Although the microscope itself collects raw
data, an external laptop, smartphone, or cloud-based system
performs all the processing. Power is supplied by two stock AA
batteries.
One of the device's most notable cost- and weight-cutting
features, however, is the fact that it doesn't use lenses.
Instead, it divides an inexpensive laser light source (such as
that from a laser pointer) into two beams. One of those beams is
directed to the sample being imaged, where it either passes
through or deflects off of the cells or particles. The other
beam, which serves as a reference, does not. Both beams end up
at a smartphone-grade sensor chip, which analyzes the
interference pattern that results when they meet. Once that data
has been crunched, an image of what the first beam encountered
can be produced.
Such images, obtained by causing light that has hit or passed
through an object to interfere with a neutral "reference beam,"
are what are commonly known as holograms.
Besides being little, cheap and rugged, the microscope is
also able to operate in two modes. In transmission mode it can
image large volumes of liquid such as blood or water, while
reflection mode is used for opaque materials. The spatial
resolution for both modes is reportedly similar to that offered
by low- to medium-power lenses.
Aydogan Ozcan, an associate professor of electrical
engineering and bioengineering who is leading the research, is
also in the process of forming a company to commercialize the
technology. "Global health is a big field that requires better
diagnostic tools, because resource-poor countries don't have the
infrastructure for conducting essentially accurate diagnostic
tests," he said. "There are so many problems that innovative
solutions [like this microscope] would impact."
The UCLA
research was recently published in the journal
Biomedical Optics Express.
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