Kent State Biologist Patents Simple Solution to Old Microscopy Problem
Sometimes the most complicated problems can be remedied with the simplest of solutions. Such is the premise behind a recent innovation developed by Kent State researchers Michael Model and the late Anatoly Khitrin (1955-2017).
Using a common ingredient found in any grocery store baking aisle, Model, Assistant Professor of Biological Sciences in the College of Arts and Sciences, developed a modification for microscopes that solves one of microscopy’s oldest dilemmas.
“There’s one thing for which there has never been an easy solution, and that is visualizing the vertical dimension, a sample’s thickness,” Model said. “Scientists were using very cumbersome ways to do it. But we came up with an extremely easy way, which can be realized on literally any light microscope with minimum modification.”
The solution to this problem is the food colorant acid blue 9, the same dye used to make cake icing.
“If you put a sample of live cells in a shallow chamber in their natural environment — say, water — and add acid blue 9 to the liquid, the dye stays outside of intact cells without harming them,” Model said.
Once the dye is added, red light is shined on the sample. Acid blue 9 strongly absorbs red light, so parts of the sample where cells are absent appear dark, while live cells exclude the dye, allowing more light to pass through. Cells show up red, and their brightness varies in direct relationship to their thickness.
“This is probably conceptually the simplest optical microscopic technique,” said Model, “and yet it didn’t exist until we came up with this idea 10 years ago.”
The modification follows was born from an earlier method Model and Khitrin patented for measuring the absorption and refractive index of highly-concentrated solutions.
This most recent method — dubbed transmission-through-dye, or TTD microscopy — has been used in Model’s lab for years to quantify cell volume and for other applications, but only in 2013 was he able to obtain a patent.
“There was a problem with selling it,” Model said. “The method is so inexpensive and simple, there is not much to sell, anyone could easily reproduce it in their lab.”
A slightly different type of application opened the way to commercialization. Under a regular microscope, debris and dead matter make it difficult to recognize living cells in a natural environment, such as pond water. Using TDD, everything that is not alive remains dark, while living cells and organisms stand out in bright red. Model realized that this type of application can be used in schools, and applied for a provisional patent on the idea in June 2016.
TTD microscopy was first tested in an Akron middle school in 2016 by Michael Model and Sara Raven, Assistant Professor in the Department of Education (now at Texas A&M University). With encouraging results from that study, Model approached several manufacturers of educational microscopes. One of them, Ken-A-Vision, produced a successful prototype of the TTD microscope, equipped with a built-in red LED activated with a flip of a switch. Beginning in March 2018, TTD microscopes will be available for sale through NASCO, a major distributor of education supplies based in Ft. Atkinson, Wisconsin. Their next catalog will feature Kent State’s role in developing the method.