Utilization of unmodified gold nanoparticles for label-free detection of mercury (II): Insight into rational design of mercury-specific oligonucleotides.
Colorimetric detection of mercury (II) with the use of DNA oligonucleotides and unmodified gold nanoparticles (AuNPs) as indicators has been extensively studied. This study provides in-depth insights into the rational design of mercury-specific oligonucleotides (MSO) in the biosensing system. The leftover bases of MSO, as a result of the formation of T-Hg2+-T base pairs, can adsorb on the AuNPs and hinder their aggregation at concentrations of salt. This phenomenon was directly verified by the changes in particle sizes characterized by dynamic light scattering for the first time. Based on these findings, we proposed a rational design for the MSO with approximately 20-fold improvement in detection sensitivity. The detection limit of the proposed assay decreased to 15nM with a linear working range from 50nM to 300nM for Hg2+. The cross-reactivity against eight other metal ions was negligible compared with the response to Hg2+. Considering the diverse applications of AuNPs with oligonucleotides, this study can serve as a good reference and provides important implications in sensing and DNA-directed nanoparticle assembly.
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China; Department of Environmental Engineering, NED University of Engineering and Technology, Karachi 75270, Pakistan.
Abdul Ghaffar
AG
Memon
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: xhzhou@tsinghua.edu.cn.
Xiaohong
X
Zhou
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China.
Jinchuan
J
Liu
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China.
Ruoyu
R
Wang
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China.
Lanhua
L
Liu
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China.
Bofan
B
Yu
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: hemiao@tsinghua.edu.cn.
Miao
M
He
Center for Sensor Technology of Environment and Health, State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China.
Hanchang
H
Shi
D015374:Biosensing Techniques; D002138:Calibration; D003124:Colorimetry; D003429:Cross Reactions; D006046:Gold; D007700:Kinetics; D008027:Light; D057230:Limit of Detection; D008628:Mercury / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009841:Oligonucleotides / Q000138:chemical synthesis* / Q000737:chemistry; D010316:Particle Size; D012542:Scattering, Radiation
D009841:Oligonucleotides; D006046:Gold; D008628:Mercury
Colorimetry; Label-free detection; Mercury (II) ion; Mercury-specific oligonucleotides; Unmodified gold nanoparticles