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. 2011;11(3):2700-14.
doi: 10.3390/s110302700. Epub 2011 Mar 1.

A nanosensor for TNT detection based on molecularly imprinted polymers and surface enhanced Raman scattering

Ellen L Holthoff  1 , Dimitra N Stratis-Cullum, Mikella E Hankus
Affiliations

A nanosensor for TNT detection based on molecularly imprinted polymers and surface enhanced Raman scattering

Ellen L Holthoff et al. Sensors (Basel). 2011.

Abstract

We report on a new sensor strategy that integrates molecularly imprinted polymers (MIPs) with surface enhanced Raman scattering (SERS). The sensor was developed to detect the explosive, 2,4,6-trinitrotoluene (TNT). Micron thick films of sol gel-derived xerogels were deposited on a SERS-active surface as the sensing layer. Xerogels were molecularly imprinted for TNT using non-covalent interactions with the polymer matrix. Binding of the TNT within the polymer matrix results in unique SERS bands, which allow for detection and identification of the molecule in the MIP. This MIP-SERS sensor exhibits an apparent dissociation constant of (2.3 ± 0.3) × 10(-5) M for TNT and a 3 μM detection limit. The response to TNT is reversible and the sensor is stable for at least 6 months. Key challenges, including developing a MIP formulation that is stable and integrated with the SERS substrate, and ensuring the MIP does not mask the spectral features of the target analyte through SERS polymer background, were successfully met. The results also suggest the MIP-SERS protocol can be extended to other target analytes of interest.

Keywords: explosives detection; molecular imprinting; sensor; surface enhanced Raman scattering.

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Figures

Figure 1.
Figure 1.
MIP-SERS detection concept.
Figure 2.
Figure 2.
Reaction protocol for producing an integrated MIP-SERS sensor.
Figure 3.
Figure 3.
SERS spectral signature of (a) TNT, (b) 2,4-DNT, (c) 1,3-DNB, and (d) 2,6-DNT on Klarite®. Spectra are offset for clarity. The vertical dashed lines are aligned with the characteristic NO2 out-of-plane bending and stretching modes of TNT.
Figure 4.
Figure 4.
(a) SEM image of a Klarite® substrate showing the smooth inactive border and the SERS-active patterned grid area. The black and red arrows illustrate the measurement areas for the Raman and SERS spectra, respectively. SERS (b) and Raman (c) spectra recorded for a TNT-doped xerogel film. The vertical lines indicate the peaks related to TNT, which are not evident in the Raman spectra.
Figure 5.
Figure 5.
SERS spectra recorded for (a) free template TNT, (b) TNT-doped xerogel film (MIP), (c) control A, and (d) control B. Spectra are offset for clarity. The vertical dashed lines indicate the peaks related to TNT, which are not evident in the control spectra.
Figure 6.
Figure 6.
SERS spectra recorded for a TNT-doped xerogel film before (—) and after (– ··–) TNT extraction. Spectra are offset for clarity. The vertical dashed lines indicate the peaks related to TNT, which decreased after template extraction.
Figure 7.
Figure 7.
SERS spectra recorded for (a) MIP, (b) control A, and (c) control B after incubation in a 4.0 × 10−4 M solution of TNT. Spectra are offset for clarity. The vertical dashed lines indicate the peaks related to TNT, which increased after incubation.
Figure 8.
Figure 8.
Response profiles for a MIP and control A and B films integrated with a Klarite® substrate.
Figure 9.
Figure 9.
SERS spectra recorded for a MIP after incubation in a 7.5 × 10−5 M solution of (a) TNT, (b) 2,4-DNT, (c) 1,3-DNB, and (d) 2,6-DNT. The vertical dashed lines are aligned with the characteristic NO2 out-of-plane bending and stretching modes of TNT. Spectra are offset for clarity.
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References

    1. Narayanan A, Varnavski OP, Swager TM, Goodson T. Multiphoton fluorescence quenching of conjugated polymers for TNT detection. J. Phys. Chem. C. 2008;112:881–884.
    1. Yang JS, Swager TM. Fluorescent porous polymer films as TNT chemosensors: Electronic and structural effects. J. Am. Chem. Soc. 1998;120:11864–11873.
    1. Yang JS, Swager TM. Porous shape persistent fluorescent polymer films: An approach to TNT sensory materials. J. Am. Chem. Soc. 1998;120:5321–5322.
    1. Pinnaduwage LA, Yi D, Tian F, Thundat T, Lareau RT. Adsorption of trinitrotoluene on uncoated silicon microcantilever surfaces. Langmuir. 2004;20:2690–2694. - PubMed
    1. Pinnaduwage LA, Wig A, Hedden DL, Gehl A, Yi D, Thundat T, Lareau RT. Detection of trinitrotoluene via deflagration on a microcantilever. J. Appl. Phys. 2004;95:5871–5875.

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