A gem of an idea
Optical imaging device instantly captures the brilliance of living cells in action

BY SHAWN HUTCHINS
Special to Rice News

Just as a gemologist looks at carat, color, cut and clarity to maximize the brilliance of a diamond, Rice University researcher Tomasz Tkaczyk works to manipulate light when building high-performance optical imaging systems that display an array of cellular and subcellular profiles.

	Snapshot IMS images of fluorescent labeled cells. A total of 19 images and one merged image (top left) are shown out of 60 available spectral channels. The different colors reveal cellular dynamics and components such as actin, mitochondria and nuclei.

The most recent platform technology to emerge from his Modern Optical Instrumentation and Bio-imaging Laboratory at Rice’s BioScience Research Collaborative uses hyperspectral fluorescence microscopy to instantly capture the brilliance of living cells in action.

The technique called image mapping spectrometry (IMS) uses a specialized compact camera that couples with any high-resolution microscope, endoscope or camera system to see a biological sample’s chemical and physical composition. Details are reported in the July 5 Optics Express.

“IMS technology is designed to preserve the most light possible and specify a range of cellular dynamics from the lightest to the darkest parts of the image,” said Tkaczyk, an assistant professor in both bioengineering and electrical and computer engineering. ”When cells are illuminated, they fluoresce and are imaged under a microscope. The hyperspectral component then instantly reveals biochemical composition, chromosome dynamics and gene expression in an array of color.”

Tkaczyk and bioengineering graduate students Robert Kester and Liang Gao built the camera through an exploratory research grant by the National Institutes of Health. Recent tests have proven its potential as a fundamental research tool for microscopy; however, IMS technology can also be used in a variety of industries, such as security, oil exploration, quality control and research.

In a single snapshot and without the use of scanning techniques, the camera captures a specimen and separates it into zones using an image mapper, which is a series of long, thin, multi-angled mirror facets.

Top: The image mapper with its 250 mirror facets next to a U.S. quarter. Bottom: Close-up side view of the image mapper showing the excellent alignment of the facets.

A sequence of components that include specialized lenses and a prism then work to spread the image into multiple spectral wavelengths and acquire a 250-nanometer visible-light range. A high-resolution digital camera captures this array of information and correlates each active pixel with the encoded spatial and spectral information. This volume of information, called a voxel, is assembled like a jigsaw puzzle by a laptop computer to instantaneously produce a 3-D data cube that can be used at the cellular level for the discrimination of fluorophores, or at the tissue level for in vivo clinical diagnostics.

”The nonscanning, snapshot nature of the system allows us to image for extended periods of time without photo bleaching,” Tkaczyk said.

IMS technology has the potential to become an indispensable tool. When combined with the use of multiple dyes, or molecular-specific optically active contrast agents, and the expertise and resources of the Texas Medical Center, the process can improve diagnostic decisions and the monitoring of diseases.

A patent application has been submitted, and earlier this spring Tkaczyk and Kester co-founded Rebellion Photonics based on the IMS technology. They are investigating avenues to commercialize the technology with the company’s CEO and Rice alumna Allison Lami.

Research in Tkaczyk’s laboratory focuses on the development and application of novel imaging instruments and systems that are inexpensive and adaptable to mass production. The compact size and performance capabilities of the platform technologies provide high-resolution and multidimensional biological content and have potential for point-of-care diagnostics in various clinical settings around the world.

–-Shawn Hutchins is a staff writer in the Department of Bioengineering.