Detection and Identification of Nerve Toxins via Transmission and Reflection Chemoresponsive Polymer Diffraction GratingsPublic Deposited
Transmission and reflection diffraction gratings were fabricated by micropatterning polymers on transparent substrates and drop-coating polymers onto etched silicon wafers. Exposure of these gratings to three nerve toxin mimics at very low concentrations resulted in mimic sorption by the polymers, changing the polymer’s refractive index. As a result, the grating’s refractive index changed, giving rise to a change in the diffractive efficiency of the system. This change is readily measured by monitoring the ratio of intensity of spots of the resulting diffraction pattern. It was found that different polymer/analyte combinations give rise to different signal shapes and intensity. An array of two polymers, poly(epichlorohydrin) and BSP3 , was created to detect and identify nerve toxin mimics dimethyl methylphosphonate, ethyl methyl phosphonate, and pinacolyl methylphosphonate. The simple array was able to differentiate one of three nerve toxins using diffraction.