Since September 11, 2001, Americans are much more aware of threats to homeland security.  As a result, the U.S. has heightened security, particularly against one form of threat: chemical warfare.   Chemical warfare is particularly frightening because  it threatens citizens’ health and can result in lasting damage to the environment, devastating all aspects of life: water, soil, and air.  But how can one protect against such a weapon?

Dr. Hai-Feng (Frank) Ji, a professor and researcher at Louisiana Tech University, has the answer. He is working on a sensor that will detect possible chemical warfare threats.  A sensor that is extremely sensitive to chemical agents is the goal, and Dr. Ji also endeavors to create  a fast, inexpensive, and durable sensor to maximize its versatility. Dr. Ji chose this particular project to work on mainly because of the impact it will have on homeland security and the technology that is involved with developing a sensor that has the advantage of heightened sensitivity.  This project is an addition to an environmental application project that he worked on four years ago.  His hope for his project is that, “Eventually the society can benefit from the project.  It will have an impact on students at Louisiana Tech, the local community, and businesses all over North Louisiana.”

The current stage of this project involves designing sensitive sensors that are composed of multilayer-modified microcantilevers.  The reasons that these microcantilever sensors are so useful is that they meet the requirements of “sensitivity, small size, automatic operation, low cost, ruggedness, and most importantly, simultaneous multiple species detection,” explains Dr. Ji. These sensors are the optimum devices for detecting the test vapor samples without including volatile acids or bases.  The enzyme coating that is applied to the sensors reacts with the vapors of the dangerous substances.  In the reaction below, water, and OPH are added to a suspicious compound, the parathion.  The sensors will detect the acid that is formed and decide if the acid is harmful or not.  The sensors are strong enough to detect a part-per-billion of a dangerous vapor.  Dr. Ji’s design is a novel technique in his field.

 

Reaction Mechanism:  a parathion can be hydrolyzed by OPH to an acid and a p-nitrophenol

Currently the project is moving forward and has produced positive data. Dr. Ji has developed the dual microcantilevers and a cantilever array in his lab, which is made possible by the funding he has received from the National Science Foundation.  The Louisiana Tech professor is the first person to develop this multilayer microcantilever system, and he is in the process of having a patent approved.  He plans to have several publications on his findings available by the end of the year.  More information on this project and others can be accessed on the web at http://www2.latech.edu/~hji.