Electrochemiluminescence-based detection method of lead(II) ion via dual enhancement of intermolecular and intramolecular co-reaction.
A novel analytical method to design a highly selective and sensitive detection technique for lead(II) ions (Pb(2+)) detection was developed based on an electrochemiluminescence (ECL) sensor, taking advantage of the high specificity of the aptamer for Pb(2+) and the use of both intermolecular and intramolecular co-reaction to achieve signal enhancement. For sensing interface construction, L-cysteine (Cys) and gold nanostructured layers were electrodeposited on the electrode surface successively, which afforded a large surface area to anchor massive thiol-terminated auxiliary probes (APs) via a thiol-Au interaction. Then, a DNA duplex was generated based on the hybridization of the APs with capture probes (CPs, Pb(2+) specific aptamers). In the presence of Pb(2+), Pb(2+)-induced aptamers were released from the DNA duplex via the formation of a Pb(2+)-stabilized G-quadruplex, accompanied by leaving the single CPs on the sensing interface. Herein, the ruthenium(ii) complexes with functional groups of -COOH (Ru-COOH) were covalently bonded on the polyamidoamine dendrimers with amine end groups (PAMAM), which were capped by the high-index-faceted Au nanoparticles (HIFAuNPs) to obtain the ECL signal labels of Ru-PAMAM-HIFAuNPs. Then, the detection probes (DPs) of amino-terminated Pb(2+) specific aptamers were tagged with the Ru-PAMAM-HIFAuNPs. It was demonstrated that the covalent bonding of PAMAM and Ru-COOH could generate a self-enhanced ECL luminophore by an intramolecular co-reaction and the use of a Cys layer modified electrode could enhance the ECL by the intermolecular co-reaction of Cys and Ru-COOH, which lead to a significant enhancement of the ECL response. Based on this analytical method, the ECL signal increased with Pb(2+) concentration which presented a linear relationship in the range 1.0 × 10(-13)-1.0 × 10(-7) M with the detection limit of 4.0 × 10(-14) M. The proposed approach was also successfully utilized for the determination of Pb(2+) in soil samples.
College of Resources and Environments, Southwest University, Chongqing 400715, P. R. China. gaoming@swu.edu.cn.
Wei
W
Deng
Lin-Ru
LR
Hong
Min
M
Zhao
Ying
Y
Zhuo
Ming
M
Gao
D052157:Aptamers, Nucleotide / Q000378:metabolism; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D050091:Dendrimers / Q000737:chemistry; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D007854:Lead / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D008163:Luminescent Measurements; D053768:Metal Nanoparticles / Q000737:chemistry; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D012987:Soil / Q000737:chemistry
D052157:Aptamers, Nucleotide; D015342:DNA Probes; D050091:Dendrimers; C104700:PAMAM Starburst; D012987:Soil; D007854:Lead; D006046:Gold