Core/Shell Quantum Dots and Au Nanoparticles Assembly for Effective Detection of Nerve Agent Mimic

doi:10.15541/jim20180486

Abstract

Abstract:

A novel assembly of CdSe/12ZnS core/shell quantum dots (CdSe/12ZnS QDs) and gold nanoparticles (Au NPs) was constructed for highly sensitive detection of nerve agent mimic diethyl cyanophosphonate (DCNP). Due to fluorescence resonance energy transfer (FRET) from CdSe/12ZnS QDs to Au NPs, the emission intensity of QDs was quenched. Thiocholine generated in situ from acetylcholinesterase (AChE) and acetylthiocholine (ATC) would destroy the assembly structure to recover the emission of QDs. However, diethyl cyanophosphonate (DCNP) could inhibit the activity of AChE, thus leading to the suppressed fluorescence recovery. Therefore, the detection of DCNP was achieved by evaluating fluorescence recovery efficiency of QDs. Optimally, a linear relationship between fluorescence recovery efficiency of QDs and logarithmic concentration of DCNP was observed in a range of 5.0×10 ^-9 mol/L to 5.0×10 ^-4 mol/L. As a result, the limit of detection (LOD) was deternimed to be as low as 5.0×10 ^-9 mol/L.

Key words: quantum dots, gold nanoparticles, nerve agents mimic, fluorescence resonance energy transfer

CLC Number:

TN304

LI Sheng-Song, ZHENG Yong-Chao, MENG Shu-Lin, WU Li-Zhu, ZHONG Jin- Yi, ZHAO Chong-Lin. Core/Shell Quantum Dots and Au Nanoparticles Assembly for Effective Detection of Nerve Agent Mimic[J]. Journal of Inorganic Materials, 2019, 34(8): 893-898.

Figures/Tables 7

Fig. 1 Illustration of the construction of QDs/Au NPs assembly

Fig. 2 TEM images of (a) Au NPs, (b) QDs and Au NP/QDs assembly, and (d) HRTEM image of Au NP/QDs assembly

Fig. 3 (a) UV-Vis absorption spectrum of Au NPs and emission spectrum of CdSe/12ZnS QDs excited at 400 nm. The inset is the emission spectra of CdSe QDs/Au NPs complex before (black) and after (red) addition of AChE and ATC; (b) Emission spectra of different systems. The concentration of QDs, Au NPs, ATC, AchE, and DCNP are 70 nmol/L, 3.5 nmol/L, 0.05 mmol/L, 1.0×10-3 U/L and 5.0×10-6 mol/L, respectively

Fig. 4 (a) Emission intensity of QDs before and after forming assembly and (b) quenching efficiency (FQ/FQ0) with different Au NPs (7 nmol/L) to QDs ratio

Fig. 5 Fluorescence recovery of the system in the presence of AChE (1.0×10-7~1.0×10-1 U/L)

Fig. 6 (a) Emission spectroscopy of system in presence of different concentrations of DCNP (5.0×10-9~5.0×10-4 mol/L) with inset showing the corresponding picture of solutions (DCNP increase from left to right); (b) FR/FR0 varied as a function of concentration of DCNP with inset showing the linear calibration of FR/FR0 on the logarithmic concentration of DCNP

Fig. 7 Fluorescence recovery of the system in the presence of DCNP (5×10-4 mol/L) premixed with different disruptors (5×10-4 mol/L)

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