Journal
BIOSENSORS & BIOELECTRONICS
Volume 69, Issue -, Pages 106-112Publisher
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2015.02.027
Keywords
Photocathode; PbS quantum dots; Enzyme mimetics; Catalase; Photoelectrochemical biosensor
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Funding
- National Natural Science Foundation of China [21275065, 21005031]
- Fundamental Research Funds for the Central Universities [JUSRP51314B]
- MOE & SAFEA for the 111 Project [B13025]
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Photocathode based on p-type PbS quantum dots (QDs) combing a novel signal amplification strategy utilizing catalase (CAT) mimetics was designed and utilized for sensitive photoelectrochemical (PEC) detection of DNA. The bio-bar-coded Pt nanoparticles (NPs)/G-quadruplex/hemin exhibited high CAT-like activity following the Michaelis-Menten model for decomposing H2O2 to water and oxygen, whose activity even slightly exceeded that of natural CAT. The bio-bar-code as a catalytic label was conjugated onto the surface of PbS QDs modified electrodes through the formed sandwich-type structure due to DNA hybridization. Oxygen in situ generated by the CAT mimetics of the bio-bar-code of Pt NPs/G-quadruplex/hemin acted as an efficient electron acceptor of illuminated PbS QDs, promoting charge separation and enhancing cathodic photocurrent. Under optimal conditions, the developed PEC biosensor for target DNA exhibited a dynamic range of 0.2 pmol/L to 1.0 nmol/L with a low detection limit of 0.08 pmol/L. The high sensitivity of the method was resulted from the sensitive response of PbS QDs to oxygen and the highly efficient CAT-like catalytic activity of the bio-bar-coded Pt NPs/G-quadruplex/hemin. (C) 2015 Elsevier B.V. All rights reserved.
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