Highly sensitive and selective electrochemical detection of Hg(2+) through surface-initiated enzymatic polymerization.
Biosens Bioelectron
; 80: 105-110, 2016 Jun 15.
Article
in En
| MEDLINE
| ID: mdl-26807524
ABSTRACT
A Hg(2+) electrochemical biosensor is developed by integrating thymine-Hg(2+)-thymine (T-Hg(2+)-T) base pairs for the high selectivity with surface-initiated enzymatic polymerization (SIEP) for signal amplification. The fabrication begins with the covalent conjugation of capture DNA probe labeled with thiol at its 3'terminal onto the gold electrode. The presence of Hg(2+) leads to DNA hybridization, in which complementary DNA was captured onto the biosensor surface, which subsequently catalyzed the addition of deoxynucleotides (dNTP) containing biotinlated 2'-deoxyadenosine 5'-triphosphate (biotin-dATP) by terminal deoxynucleotidyl transferase (TdT). The binding between biotin and strepavidin leads to the attachment of a large number of strepavidin functionalized silver nanoparticles (strepavidin-AgNPs), which could generate electrochemical stripping signal of silver to monitor the concentration of Hg(2+) in KCl solution. Through utilizing the T-Hg(2+)-T selectivity and SIEP amplification, this assay method can detect aqueous Hg(2+) with a wide linear range from 0.05 nM to 100 nM and a detection limit of 0.024 nM. The application of this sensor in the analysis of drinking water demonstrates that the proposed method works well for real samples.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Drinking Water
/
Biosensing Techniques
/
Electrochemical Techniques
/
Mercury
Type of study:
Diagnostic_studies
Limits:
Humans
Language:
En
Journal:
Biosens Bioelectron
Journal subject:
BIOTECNOLOGIA
Year:
2016
Document type:
Article