Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Apr 21;5(17):9668-9673.
doi: 10.1021/acsomega.9b03844. eCollection 2020 May 5.

NTO Sensing by Fluorescence Quenching of a Pyoverdine Siderophore-A Mechanistic Approach

Prashant A Kulkarni  1 , Vinod Nandre  2 , Navanath Kumbhar  2 , Rahul Khade  2 , Tukaram Urmode  2 , Kisan M Kodam  2 , Mahendra A More  1
Affiliations

NTO Sensing by Fluorescence Quenching of a Pyoverdine Siderophore-A Mechanistic Approach

Prashant A Kulkarni et al. ACS Omega. .

Abstract

In this study, a siderophore, pyoverdine (PVD), has been isolated from Pseudomonas sp. and used to develop a fluorescence quenching-based sensor for efficient detection of nitrotriazolone (NTO) in aqueous media, in contrast to other explosives such as research department explosive (RDX), picric acid, and trinitrotoulene (TNT). The siderophore PVD exhibited enhanced fluorescence quenching above 50% at 470 nm for a minimal concentration (38 nM) of NTO. The limit of detection estimated from interpolating the graph of fluorescence intensity (at 470 nm) versus NTO concentration is found to be 12 nM corresponding to 18% quenching. The time delay fluorescence spectroscopy of the PVD-NTO solution showed a negligible change of 0.09 ns between the minimum and maximum NTO concentrations. The in silico absorption at the emission peak of static fluorescence remains invariant upon the addition of NTO. The computational studies revealed the formation of inter- and intramolecular hydrogen-bonding interactions between the energetically stable complexes of PVD and NTO. Although the analysis of Stern-Volmer plots and computational studies imply that the quenching mechanism is a combination of both dynamic and static quenching, the latter is dominant over the earlier. The static quenching is attributed to ground-state complex formation, as supported by the computational analysis.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Fluorescence response of PVD toward the detection of various explosives: (a) pristine PVD without any explosive, (b) picric acid, (c) TNT, (d) RDX, and (e) NTO (λexc = 360 nm, λem = 470 nm, 2.5 μm slit width).
Figure 2
Figure 2
Overall fluorescence response of PVD–NTO solutions (with increasing NTO concentrations, left to right) upon illumination with (A) visible light, (B) wide-band UV lamp, (C) UV source ∼265 nm, and (D) UV source ∼365 nm.
Figure 3
Figure 3
Fluorescence response of pyoverdine upon the addition of various concentrations of NTO (at λexc = 360 nm and 2.5 μm slit width).
Figure 4
Figure 4
Combined S–V plot for steady-state fluorescence and excited-state lifetime plot of pyoverdine with NTO.
Figure 5
Figure 5
Excited-state lifetime plots with excitation at 374 nm.
Figure 6
Figure 6
Molecular interactions from the optimized stable complex of pyoverdine with NTO.
See this image and copyright information in PMC

References

    1. Steinfeld J. I.; Wormhoudt J. Explosive detection: A challenge for physical chemistry. Annu. Rev. Phys. Chem. 1998, 49, 203–232. 10.1146/annurev.physchem.49.1.203. - DOI - PubMed
    1. Singh S. Sensors—An effective approach for the detection of explosives. J. Hazard. Mater. 2007, 144, 15–28. 10.1016/j.jhazmat.2007.02.018. - DOI - PubMed
    1. Sun X. C.; Wang Y.; Lei Y. Fluorescence based explosive detection: from mechanisms to sensory materials. Chem. Soc. Rev. 2015, 44, 8019–8061. 10.1039/C5CS00496A. - DOI - PubMed
    1. Chen D. M.; Tian J. Y.; Liu C. S. A luminescent Li(I)-based metal–organic framework showing selective Fe(III) ion and nitro explosive sensing. Inorg. Chem. Commun. 2016, 68, 29–32. 10.1016/j.inoche.2016.03.023. - DOI
    1. Gole B.; Bar A. K.; Mukherjee P. S. Fluorescent metal–organic framework for selective sensing of nitroaromatic explosives. Chem. Commun. 2011, 47, 12137–12139. 10.1039/c1cc15594f. - DOI - PubMed