Microfluidic chip with optical sensor for rapid detection of nerve agent Sarin in water samples

Abstract

The chemical warfare agent Sarin is an organophosphate that is highly toxic to humans as they can act as cholinesterase inhibitors, that disrupts neuromuscular transmission. As these nerve agents are colorless, odorless and highly toxic, they can be introduced into drinking water as a means of terrorist sabotage. Hence, numerous innovative devices and methods have been developed for rapid detection of these organophosphates. Microfluidic technology allows the implementation of fast and sensitive detection of Sarin. In this paper, a micro-total analysis systems (TAS), also known as Lab-on-a-chip, fitted with an optical detection system has been developed to analyze the presence of the nerve agent sarin in water samples. In the present set-up, inhibition of co-introduced cholinesterase and water samples containing trace amounts of nerve agent sarin into the microfluidic device was used as the basis for selective detection of sarin. The device was fabricated using polymeric micromachining with PMMA (poly (methymethacrylate)) as the substrate material. A chromophore was utilized to measure the activity of remnant cholinesterase activity, which is inversely related to the amount of sarin present in the water samples. Comparisons were made between two different optical detection techniques and the findings will be presented in this paper. The presented measurement method is simple, fast and as sensitive as Gas Chromatography.

An Integrated Portable Multiplex Microchip Device for Fingerprinting Chemical Warfare Agents

“…The prevailing CE-based detection techniques for CWAs are UV [27,28,29] and conductivity detection. Of all the aforementioned techniques, the microfluidics-based LOC concept is the most attractive for identification of chemical and biological warfare agents in the field due to its inherent potential for the integration of filtration, preconcentration, separation, and detection on one platform [16,30,31,32,33,34,35,36]. Microchip capillary electrophoresis (MCE) was the electrophoretic sample separation method adopted for LOC devices, and the capacitively coupled contactless conductivity detection (C 4 D) was the detection method of choice.…”

Development of a lab on a chip for nerve agent detection

“…A number of papers have reported on using LOC to detect the presence of CWA or degraded products in the presence of aqueous medium [12,14,[21][22][23][24][25][26][69][70][71] . Hadd et.…”

“…As preliminary works for this project, the candidate had investigated the presence of trace amounts of nerve agent sarin in water samples [25] ; and also trace amounts of sarin regenerated from spiked blood samples [26] . In these preliminary works, the LOC was made from PMMA using laser micromachining and reagents were introduced into the LOCs using an external syringe pump.…”

“…al. [25] reported setting the flow rate of 4.0 µl/min at which the reagents (DTNB, Turbulence and chaotic advection are the two forms of flows that are being introduced to fluids to enhance mixing [51,75] . Chaotic advection is not turbulence and it can be created in a simple two-dimensional flow using time dependent disturbance or in a three-dimensional flow without time dependent disturbance.…”