Tools of the Trade

Victoria Huntress zooms in on a 3-D image of human skin cells using the confocal microscope in WPI’s Life Sciences and Bioengineering Center.

Exploring the Microscopic World in 3-D

by Funmi Adebayo ’11

From blockbuster movies to virtual reality games to broadcast TV, everything seems to be going 3-D these days — including scientific research. Scientists have always been fascinated by objects invisible to the naked eye. Since the 17th century, they have been using light microscopes to see into the mysterious world of tiny objects. But until recently, such journeys have been made only in 2-D.

Now imagine that you could put on a pair of 3-D glasses and peer into the depths of microscopic matter. That’s the idea behind the confocal microscope. While not literally a pair of glasses, the confocal microscope has allowed scientists to create 3-D images of minute objects for the past two decades. Invented in the 1950s by Marvin Minsky (better known for his work in artificial intelligence), the technology has been used extensively within the biological sciences, as well as a number of other fields.

Confocal microscopes work by scanning a sample vertically with a laser. The light, either directly reflected by a surface or, in the case of many biological applications, emitted by fluorescent dyes, is focused onto a pinhole that allows only light from a single focal plane — in essence, a thin, 2-D horizontal slice of the object — to pass through to a detector. Moveable mirrors enable the sweeping laser beam to make repeated scans at different focal planes. A computer assembles these scans to produce a 3-D image, which scientists can rotate and zoom in on to reveal details from multiple angles.

WPI has two confocal microscopes that have proven useful in a wide range of applications. One, located in the Life Sciences and Bioengineering Center at Gateway Park, is employed for a wide range of imaging work in the life sciences. Under the direction of Victoria Huntress, microscopy/imaging technology manager in WPI’s Department of Biology and Biotechnology, it has examined Physcomitrella patens, a moss being used as a model organism for study of the molecular mechanisms of cell division and expansion, and created 3-D images of fibrin threads that WPI biomedical engineers are developing to deliver adult stem cells to the body.

From left: silicon wafer pads, carpet sample, mouse intestines

Installed in the Surface Metrology Laboratory, a scanning laser confocal microscope entrusted to the lab by Olympus Industrial Microscopes of Olympus America Inc. has become an important tool for studying the texture and roughness of surfaces of all kinds. Led by Chris Brown, professor of mechanical engineering, the lab uses the microscope to make quantitative, topographic measurements in 3-D of objects ranging from the pads used to make silicon wafers to zebra mussel shells. In one recent study, conducted with Jainshun Zhang at Syracuse University, the lab put carpet samples under the microscope to learn more about the tendency of carpets to collect particles from the air. The work will support the design of healthier buildings. “We’re grateful to Olympus for not only expanding our research capabilities, but recognizing the global leadership position of the Surface Metrology Lab,” Brown says. 

Whether charting the three-dimensional structures of fibroblasts or measuring the differences in surface roughness between different brands of potato chips, WPI’s confocal microscopes have proven their worth in a wide variety of applications, giving researchers a view of an amazing miniature world that no other microscope can offer.

Adebayo, a biomedical engineering major at WPI, is pursuing a minor in professional writing.

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