Toussaint tackles problems in biological imaging and nanotechnology

MechSE associate professor Kimani C. Toussaint, Jr. has been awarded an appointment as a Dr. Martin Luther King, Jr. Visiting Associate Professor at the Massachusetts Institute of Technology (MIT) for the 2014-2015 academic year, as part of his sabbatical.

"MLK visitors are chosen for the contributions they have made to their profession, and for their potential contributions to the intellectual life of MIT," said his appointment letter.

During his time at MIT, Toussaint will explore ways in which the nonlinear optical microscopy technology that his lab specializes in can be used for quantitative imaging of neurons.

"My time here has been great,” Toussaint said. “It's very educational to learn about both the needs and challenges with functional imaging of neurons. It's a major area of research."

He joined MechSE in the Fall semester of 2007, after working as a Postdoctoral Researcher at the prestigious James Franck Institute at the University of Chicago. Prior to that he received his Ph.D. in Electrical Engineering from Boston University, where his research focused on quantum entanglement of photons. Due to his multidisciplinary background and research focus he also maintains Affiliate Faculty positions in the Departments of Electrical and Computer Engineering, and Bioengineering at the University, as well as in the Department of Ophthalmology and Visual Sciences on the Chicago campus. He is also an Affiliate Faculty in the prestigious Beckman Institute for Advanced Science and Technology.

Toussaint directs the laboratory for Photonics Research of Bio/nano Environments (PROBE Lab) at UIUC, an interdisciplinary research group which focuses on developing advanced optical techniques for both quantitatively imaging collagen-based biological structures, and investigating the optical properties of plasmonic nanostructures for light-driven control of matter.

In 2010, Toussaint received a 2010 NSF CAREER Award, and he holds Senior Member positions in the Optical Society of America (OSA), the Institute of Electrical and Electronics Engineers (IEEE), and as newly named in 2014, the International Society for Optical Engineering (SPIE). Senior Membership status in these professional societies is critical in moving on to the final stage of Fellow.

Aside from his distinctions in research, Toussaint is well known for his commitment to teaching. He has been on the UIUC List of Teachers Ranked as Excellent by Their Students for 6 consecutive years.

Two newly developed technologies in particular stand out as highlights of Toussaint’s accomplishments. The first, Quantitative Second-Harmonic Generation Imaging, is an imaging technique based on the nonlinear optical process of second-harmonic generation (SHG), whereby intense, input probe light is converted to light at half the wavelength (or twice the frequency) of the original. This occurs only for special materials like certain nonlinear optical crystals and biological systems with spatially-ordered molecular arrangements such as fibrous collagen tissues found in tendon, the eye, and bone, as examples. Toussaint’s PROBE Lab has developed quantitative SHG imaging as a reliable, non-destructive method for primarily quantifying the spatial organization of collagen fibers in tissues in 3D and with high spatial resolution. Information obtained from such measurements could be useful in helping biologists and engineers understand the structure-function relationship in complex tissues.

The second notable technology involves Novel Metal Nanoantennas. The PROBE Lab has developed nanoscale antennas made of gold that can manipulate and concentrate light into spatial regions smaller than an optical wavelength. These nanoantennas are shaped like tiny bowties and are often arranged in two-dimensional arrays on a glass substrate. A particularly interesting aspect of these nanoantennas is that they can enhance the intensity of concentrated light by as much as 1000 times. Toussaint’s group has used this characteristic to create nanoscale optical tweezers to move around nano- and micro-scaled objects using laser pointers and a standard microscope. The enhanced optical forces associated with these nanotweezers is rich in complex physics that governs its operation and has the potential to result in specialized lab-on-a-chip devices for point-of-care diagnostics.