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

• Main Authors: Yue Wang, Menghua Lv, Zehan Chen, Zilong Deng, Ningtao Liu, Jianwei Fan, Weixian Zhang
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-04-01
• Series: Frontiers in Chemistry
• Subjects: upconversion nanoparticles; gold nanoparticles; fluorescence resonance energy transfer; DNA; lead ions
• Online Access: https://www.frontiersin.org/article/10.3389/fchem.2020.00238/full

We report a new sensor for the specific detection of lead ions (Pb2+) 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 Pb2+ 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 Pb2+, the FRET process was broken because Pb2+ 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 Pb2+ 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 Pb2+ 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.