A simple rig consisting of a smartphone and a box made from Lego® bricks could help first responders and researchers in austere environments identify nerve agents such as VX and sarin.
The device uses affordable, accessible materials to make a chemical sensor based on florescence, using a compound which generates different colors to signal which of several nerve agents are present and how much.
Researchers at The University of Texas at Austin wanted to make this process more useful in real-world scenarios, which hinged on creating a light-tight space to get a good reading of the signals on the smartphone camera.
They considered 3D-printing a box but realized that 3D printers and the materials used in them can be inaccessible, uneven or cost-prohibitive in some parts of the world. That’s when Pedro Metola, a clinical assistant professor at UT, thought of using Legos.
“Unfortunately, it can be difficult to see differences in the level of florescence with the naked eye in the field. And instruments used in the lab to measure florescence are not portable and cost $30,000,” said Sun. “This device essentially takes photographs of the glowing.
Eric Anslyn, a chemistry professor at UT Austin, has been studying nerve agents for nearly 20 years, using safe chemical compounds that behave in the same way as nerve agents and can mimic them in testing. He previously developed chemical compounds that neutralize nerve agents and at the same time create a glow bright enough to be seen with the naked eye.
“Chemical weapons are dangerous threats to humanity,” Anslyn said. “Detection and neutralization are key to saving lives.”
The camera on a smartphone is sensitive enough to detect the differences in color and brightness in the glowing reaction. The team used an iPhone in the lab. Software, developed by graduate student Alexander Boulgakov and available for free on GitHub, analyzes the color and brightness to identify the type and concentration of the nerve agent. The software can be adapted for multiple smartphone systems.
“Legos are the same everywhere you go,” Metola said.
The only other pieces of equipment needed are an ultraviolet light and standard 96-well test plate. The solution is inexpensive, portable and adjustable on the fly.
Funding for the research was provided by the U.S. Department of Defense’s Defense Threat Reduction Agency, the Welch Foundation, the National Institutes of Health and the National Science Foundation.
Read more: Photography Coupled with Self-Propagating Chemical Cascades: Differentiation and Quantitation of G- and V-Nerve Agent Mimics via Chromaticity. DOI: 10.1021/acscentsci.8b00193
Source: The University of Texas at Austin, adapted