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Jiang H.,Key Laboratory of Chemical Biosensing | Jiang H.,Key Laboratory of Functional Molecular Solids | Jiang H.,Anhui Normal University | Zhang X.,Key Laboratory of Chemical Biosensing | And 6 more authors.
Biosensors and Bioelectronics | Year: 2015

Due to terbium's unique photophysical properties, nucleic-acid-sensitized terbium (DNA/Tb3+) bioluminescent system becomes a potential candidate for the fabrication of DNA biosensors. However, the low sensitivity of DNA/Tb3+ bioluminescent system limits its development. In this paper, a strategy combining autocatalytic multi-cycle-amplification (including exonuclease III (exo III)-aided and Zn2+-requiring DNAzyme-assisted target recycling amplifications) and magnetic nanoparticles assisted-background-lowering to improve the sensitivity of DNA/Tb3+ bioluminescent system is presented for sensitive detection of target DNA (tDNA). The DNA/Tb3+ bioluminescent system was investigated by ultraviolet-visible (UV-vis) absorption and luminescence spectra. The possible conjugation mechanism and mode of DNA with Tb3+ were discussed. The autocatalytic multi-cycle-amplification effect was investigated by the comparison of the luminescence. The carboxylation-functionalized Fe3O4-magnetic nanoparticles (MNPs) were characterized and its role in background lowering was proved. As a result, with the designed protocol, the detection limit for the tDNA detection reached a low level to aM, which is especially exciting for the DNA/Tb3+ bioluminescent system. In the process, due to the separation effect of MNPs, the assay solution was purified to avoid the nonspecific luminescence of DNA/Tb3+, not only lowering the background signal greatly (about five times lower than that without the use of MNPs but also improving the reproducibility and stability. We hope that our attempt in this field will not only extend the application of DNA/Tb3+ luminescent system in biosensing areas but also open the road to adaptation of the protocols to other related analytes. © 2015. Source


Wang G.,Key Laboratory of Chemical Biosensing | Wang G.,Anhui Normal University | Wang G.,Hefei University of Technology | Huang H.,Key Laboratory of Chemical Biosensing | And 14 more authors.
Langmuir | Year: 2011

An electrochemical immunosensor was studied for sensitive detection of Interleukin-6 (IL-6) based on a dual amplification mechanism resulting from Au nanoparticles (AuNP)-Poly-dopamine (PDOP) as the sensor platform and multienzyme-antibody functionalized AuNP-PDOP@carbon nanotubes (CNT). The stable and robust film, PDOP, was used to immoblize biomolecules not only for the construction of the sensor platform, but also for the signal labeling. Sensitivity was greatly amplified by using the special platform of AuNP-PDOP and synthesizing horseradish peroxidase (HRP)-antibody (Ab2) functionalized AuNP-PDOP@carbon nanotubes (CNT). A linear response range of IL-6 from 4.0 to 8.0 × 102 pg mL-1 with a low detection limit of 1.0 pg mL-1 was obtained by the amperometry determination. Measurements of IL-6 in human serum gave excellent correlations with standard ELISA assays. Moreover, the immunosensor exhibited high selectivity, good reproducibility, and stability. © 2010 American Chemical Society. Source


Wang G.,Key Laboratory of Chemical Biosensing | Chen L.,Key Laboratory of Chemical Biosensing | Zhu Y.,Key Laboratory of Chemical Biosensing | He X.,Key Laboratory of Chemical Biosensing | And 2 more authors.
Biosensors and Bioelectronics | Year: 2014

Sensitive and selective sensors need to be explored to detect the physiological potassium level due to its important role in the living organisms. In the present system, a novel electron transfer mediator actuated electrocatalytical biosensor was demonstrated to assay K+ based on the conformational change of DNA. With the hybridization between the complementary bases and the self-folding of guanine-rich nucleic acid sequence, the horseradish peroxidase-mimicking enzyme (HRP-DNAzyme) was formed and brought to approach the ferrocene (Fc) unit on Au nanoparticles (AuNPs). Thus, in the system, Fc unit acted as the relay, stimulating the electrical contact of HRP-DNAzyme with the electrode to obtain the bioelectrocatalyze reduction signal. Under the Fc actuated catalysis of HRP-DNAzyme and amplification of Au nanoparticles, the obtained biosensor exhibited a sensitive detection for K+. A satisfying result of a wide linear range and low detection limit were obtained with the novel electrocatalytical biosensor which was then applied in real samples. © 2014 Elsevier B.V. Source


Wang G.,Key Laboratory of Chemical Biosensing | Wang G.,Key Laboratory of Functional Molecular Solids | Wang G.,Anhui Normal University | Wang G.,Hefei University of Technology | And 12 more authors.
Biosensors and Bioelectronics | Year: 2012

In the present study, based on a dual hairpin DNA structure, a novel system of electrically contacted enzyme and its signal amplification for ultrasensitive detection of Hg 2+ was demonstrated. In the presence of Hg 2+, with the interaction of thymine-Hg 2+-thymine (T-Hg 2+-T), DNA sequence dully labeled with ferrocene (Fc) at 5' end and horseradish peroxidase (HRP) at 3' end, hybridized to the capture probe and formed the dual hairpin structure on the electrode. Fc unit acts as a relay that electrically contacts HRP with the electrode and activates the bioelectrocatalyzed reduction of H 2O 2. And based on the bioelectrocatalyzed signal amplification of the presented system, Hg 2+ could be quantitatively detected in the range of 10 -10-10 -6M with a low detection limit of 52pM. And it also demonstrated excellent selectivity against other interferential metal ions. © 2012 Elsevier B.V. Source


Wang G.,Key Laboratory of Chemical Biosensing | Wang G.,Key Laboratory of Functional Molecular Solids | Wang G.,Anhui Normal University | Xu G.,Key Laboratory of Chemical Biosensing | And 8 more authors.
Chemical Communications | Year: 2014

With exonuclease III activity on DNA hybrids containing thymine-Hg 2+-thymine, a label-free ultrasensitive "turn-on" fluorescent sensor involving "quenching" and "reappearing" processes based on a carbon nanotube-Ag nanoclusters system is demonstrated for amplified determination of Hg2+. © 2014 The Royal Society of Chemistry. Source

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