A Complementary Silicon Quantum Dot-Enzyme Platform for the Selective Detection of Nitroaromatic Compounds: Explosives versus Nerve Agents

Abstract

To address the issue of poor selectivity in nanotechnologydriven, portable nitroaromatic sensors, we have coupled a ratiometric photoluminescent sensor based on silicon quantum dots and fluorescent proteins with a colorimetric, enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds�specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4dinitrotoluene, and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. A prototype portable sensing device housing both technologies is presented and tested for achieving visual differentiation of the nitroaromatic explosives versus nerve agents. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors that can accurately identify hazardous chemical species.

High-Temperature Anomaly in the Synthesis of Large (d > 100 nm) Silicon Nanoparticles from Hydrogen Silsesquioxane

“…In a typical experiment, 2 g of solid, white HSQ is thermally treated in a tube furnace under flowing Ar. While previous reports using HSQ or analogous materials heat samples under a mixture of 5% H 2 and 95% Ar (forming gas), − we recently discovered that H 2 is not required for nanoparticle formation. The silicon nanocrystals produced in this study target sizes too large for photoluminescence, thus, we chose to employ an atmosphere of pure Ar.…”

“…In 2006, the Veinot group developed a method for producing oxide-embedded SiNPs by thermal disproportionation of solid hydrogen silsesquioxane (HSQ) . Subsequent silicon nanoparticle research from our lab has focused on probing the internal nanoparticle structure or exploring new applications for SiNPs. − In both cases, small nanoparticles are typically targeted to achieve particle photoluminescence. While previous work has reported a positive correlation between annealing temperature and particle size, these studies stopped short of the ideal Mie scattering size window for visible wavelengths. , In this work, we target large silicon nanocrystals and expand our understanding of high-temperature treatment of HSQ.…”

Colloidal Quantum Dots for Explosive Detection: Trends and Perspectives

“…83 In particular, the superior affinity of TNT toward cysteamine triggered self-aggregation of Au nanoparticles and , where a CQDbased ratiometric sensor was coupled with a colorimetric, gelencapsulated enzymatic sensor to qualitatively detect and differentiate unknown nitroaromatic compounds. 84 The ratiometric sensor was obtained by combining the PL response of Si CQDs with the persistent PL of luminescent proteins, whereas acetylcholinesterase was chosen as the enzyme in the colorimetric assay since it was preferentially inhibited by nerve agents. The PL sensor detected TNT, DNT, and NP with micromolar LOD and the colorimetric sensor provided an accurate differentiation of hazardous nitroaromatic explosives from chemically similar nerve agents within 5−10 min.…”

“…Another successful example of multicriteria sensing is represented by the work of Milburn et al, where a CQD-based ratiometric sensor was coupled with a colorimetric, gel-encapsulated enzymatic sensor to qualitatively detect and differentiate unknown nitroaromatic compounds . The ratiometric sensor was obtained by combining the PL response of Si CQDs with the persistent PL of luminescent proteins, whereas acetylcholinesterase was chosen as the enzyme in the colorimetric assay since it was preferentially inhibited by nerve agents.…”

Zirconium-based metal–organic framework loaded agarose hydrogels for fluorescence turn-on detection of nerve agent simulant vapor

“…8 Many methods have been utilized for the detection of colorless, odorless but lethal nerve agent simulants, including electrochemical sensing, liquid chromatography-mass spectrometry, ion mobility spectrometry and techniques based on enzyme sensing. [9][10][11][12] These methods provided accurate and precise detection results, but drawbacks such as nonportability, slow response, expensive instruments and complex operation limited their application in practical assays. As an alternative to these detection methods, uorescence analysis with good sensitivity and selectivity, rapid response, and ease of operation has proven to be feasible and is superior in terms of the signal output pattern.…”