Resonance Energy Transfer-Amplifying Fluorescence Quenching at the Surface of Silica Nanoparticles toward Ultrasensitive Detection of TNT

Abstract

This paper reports a resonance energy transfer-amplifying fluorescence quenching at the surface of silica nanoparticles for the ultrasensitive detection of 2,4,6-trinitrotoluene (TNT) in solution and vapor environments. Fluorescence dye and organic amine were covalently modified onto the surface of silica nanoparticles to form a hybrid monolayer of dye fluorophores and amine ligands. The fluorescent silica particles can specifically bind TNT species by the charge-transfer complexing interaction between electron-rich amine ligands and electron-deficient aromatic rings. The resultant TNT-amine complexes bound at the silica surface can strongly suppress the fluorescence emission of the chosen dye by the fluorescence resonance energy transfer (FRET) from dye donor to the irradiative TNT-amine acceptor through intermolecular polar-polar interactions at spatial proximity. The quenching efficiency of the hybrid nanoparticles with TNT is greatly amplified by at least 10-fold that of the corresponding pure dye. The nanoparticle-assembled arrays on silicon wafer can sensitively detect down to approximately 1 nM TNT with the use of only 10 microL of solution (approximately 2 pg TNT) and several ppb of TNT vapor in air. The simple FRET-based nanoparticle sensors reported here exhibit a high and stable fluorescence brightness, strong analyte affinity, and good assembly flexibility and can thus find many applications in the detection of ultratrace analytes.

Dummy Molecularly Imprinted Polymers-Capped CdTe Quantum Dots for the Fluorescent Sensing of 2,4,6-Trinitrotoluene

“…In comparison with the other work on MIP@QDs for use in detection applications, [25][26][27][28]41,42 the developed DMIP@QDs showed excellent selectivity but low sensitivity. This problem of low sensitivity commonly exists for MIP@QDs-based systems.…”

“…27 Gao et al reported a resonance energy-transfer-amplifying fluorescence quenching at the surface of silica nanoparticles for the ultrasensitive detection of TNT. 28 Stringer et al prepared a fluorescent QDs-labeled imprinted polymer for the detection of nitroaromatic explosives in solution. 30 Instead of preparing the QDs beforehand and incorporating them into the imprinted polymers, QDs were added as a postprocessing step.…”

Molecular imprinting ratiometric fluorescence sensor for highly selective and sensitive detection of phycocyanin

“…When the excited-state electrons of the donor return to ground state through the pathway of a, b, and c, the ground-state electrons of the PC will transit to the excited states through the corresponding pathway of a′, b′, and c′, respectively, due to the polar-polar resonance of donor and acceptor. The coupled transitions will lead to the highly efficient quenching of donor fluorescence (Gao et al, 2008). On the other hand, it has to be noted that the fluorescence of donor may also be quenched by the charge transfer, as illustrated in Fig.…”

Electrospun Fluorescent Nanofibers for Explosive Detection

“…This calls in for some improvement in the sensing techniques, attracting considerable research efforts in recent years. Among the various techniques, fluorescence-based sensors appear simple, cost-effective, and highly sensitive detection modalities [13][14][15][16][17]. Adding to the list, miniaturized smart sensors based on one-dimensional (1D) nanostructures have gained much attention owing to their fast and high sensitivity towards enhanced adsorption.…”