Elsevier

Biosensors and Bioelectronics

Volume 131, 15 April 2019, Pages 119-127
Biosensors and Bioelectronics

Rapid quantification of two chemical nerve agent metabolites in serum

https://doi.org/10.1016/j.bios.2019.01.056Get rights and content
Under a Creative Commons license
open access

Highlights

  • Aptamer-based assay quantifies of OPNA with LODs of 3 pg/mL (for VX acid) and 10 pg/mL (for GB acid) in 25% serum.

  • The mix-and-read, free-solution assay (FSA) is rapid and highly selective for organophosphorous nerve agents (OPNA).

  • Using 1/5th of the volume, FSA was 130-fold more sensitive than LC-MS/MS for OPNA.

Abstract

Organophosphorus compounds (OPs) continue to represent a significant chemical threat to humans due to exposures from their use as weapons, their potential storage hazards, and from their continued use agriculturally. Existing methods for detection include ELISA and mass spectrometry. The new approach presented here provides an innovative first step toward a portable OP quantification method that surmounts conventional limitations involving sensitivity, selectivity, complexity, and portability. DNA affinity probes, or aptamers, represent an emerging technology that, when combined with a mix-and-read, free-solution assay (FSA) and a compensated interferometer (CI) can provide a novel alternative to existing OP nerve agent (OPNA) quantification methods. Here it is shown that FSA can be used to rapidly screen prospective aptamers in the biological matrix of interest, allowing the identification of a ‘best-in-class’ probe. It is also shown that combining aptamers with FSA-CI enables quantification of the OPNA metabolites, Sarin (NATO designation “G-series, B”, or GB) and Venomous Agent X (VX) acids, rapidly with high selectivity at detection limits of sub-10 pg/mL in 25% serum (by volume in PBS). These results suggest there is potential to directly impact diagnostic specificity and sensitivity of emergency response testing methods by both simplifying sample preparation procedures and making a benchtop reader available for OPNA metabolite quantification.

Keywords

Interferometry
Free Solution Assay
Organophosphorus Nerve Agents
Aptamers

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