A Fluorescence Resonance Energy Transfer Probe Based on DNA-Modified Upconversion and Gold Nanoparticles for Detection of Lead Ions

Abstract

We report a new sensor for the specific detection of lead ions (Pb 2+) in contaminated water based on fluorescence resonance energy transfer (FRET) between upconversion nanoparticles (UCNPs) as donors and gold nanoparticles (Au NPs) as receptors. The UCNPs modified with Pb 2+ aptamers could bind to Au NPs, which were functionalized with complementary DNA through hybridization. The green fluorescence of UCNPs was quenched to a maximum rate of 80% due to the close proximity between the energy donor and the acceptor. In the presence of Pb 2+ , the FRET process was broken because Pb 2+ induced the formation of G-quadruplexes from aptamers, resulting in unwound DNA duplexes and separated acceptors from donors. The fluorescence of UCNPs was restored, and the relative intensity had a significant linear correlation with Pb 2+ concentration from 0 to 50 nM. The sensor had a detection limit as low as 4.1 nM in a buffer solution. More importantly, the sensor exhibited specific detection of Pb 2+ in complex metal ions, demonstrating high selectivity in practical application. The developed FRET prober may open up a new insight into the specific detection of environmental pollution.

Gold nanoparticle-based optical nanosensors for food and health safety monitoring: recent advances and future perspectives

“…For instance, unconventional nanoparticles (UCNPs) can emit uorescence under the excitation wavelengths in the near infrared region, which is less harmful for biological samples. 89,98 Recently, graphene NPs have been regarded as a potential choice as they can be fabricated easily at large scale of production. Moreover, their cost-efficiency, high solubility and biocompatible are advantages.…”

Advances in aptamer screening and aptasensors’ detection of heavy metal ions

“…Many researchers fabricated aptasensors to detect Pb 2+ using this aptamer. For example, a novel aptasensor based on FRET was reported for detection of Pb 2+ in contaminated water by using Upconversion nanoparticles (UCNPs) as donor and gold nanoparticles (AuNPs) as acceptors [ 85 ]. The ssDNA sequence for the modified UCNPs was 5′-AAGGGTGGGTGGGT-3′, which could be folded into a G-quadruplex structure in the presence of Pb 2+ .…”

NaYF4:Yb3+(58%),Tm3+@NaYF4@Au nanocomposite for 4-nitrophenol ultrasensitive quantitative detection and highly efficient catalytic reduction

“…In order to improve the selectivity, sensitivity, and reliability of fluorescence spectral sensors, upconversion nanoparticles have been found to have unique luminescence properties by comparing various nanomaterials. 50,51 Compared with the traditional fluorescent markers, upconversion nanoparticles has the characteristics of low self-fluorescence, narrow emission width, scintillation light stability, and has been widely used in biological and environmental monitoring and sensing. [52][53][54][55][56] Furthermore, upconversion luminescence, as a sensing signal under near-infrared (NIR) excitation, can effectively reduce background noise in complex detection systems.…”