-
[show abstract]
[hide abstract]
ABSTRACT: Taking advantage of the super-quenching effect of the cationic perylene derivative on adjacent fluorophores, we for the first time reported a DNAzyme-perylene complex-based strategy for constructing fluorescence catalytic biosensors with improved sensitivity.
Chemical Communications 06/2013; · 6.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A highly sensitive electrochemical immunosensor based on combination of chitosan (CHIT) and coral-shaped AuNPs (C-AuNPs) to form an immobilization matrix has been developed using human IgG as a model analyte. The inorganic-organic hybrid film with abundant adsorbing sites and large surface area can reserve the biocompatibility of the biomaterials which greatly increase loading amounts of assembling, thus, significantly improves the performance of biosensing. The morphology is studied by scanning electron microscopy (SEM). Under the optimized experimental conditions, the immunosensor exhibits excellent performance (e.g., a detection limit of 5 pmol L(-1), a linear dynamic range of 3 orders of magnitude, high specificity). This possibly makes it an attractive platform for the direct immunoassay of human IgG or other biomolecules.
Talanta 07/2011; 85(1):117-22. · 3.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A highly sensitive and selective electrochemical DNA signaling scheme, which identifies the point mutation existing in target DNA sequence, is developed based on the combination of label-free hairpin probe (HP)/DNA endonuclease with zirconia (ZrO(2)) nanoparticle film, representing a promising screening platform for the accurate diagnosis of infections and genetic diseases as well as for environmental and forensic applications.
Chemical Communications 01/2011; 47(4):1294-6. · 6.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this contribution, an electrochemical aptameric sensing scheme for the sensitive detection of small molecules is proposed using adenosine as a target model. A ferrocene (Fc)-functionalized thiolated aptamer probe is adapted and immobilized onto an electrode surface. Introducing a recognition site for EcoRI into the aptamer sequence not only suppresses the peak current corresponding to blank sample but also provides a signal-on response mechanism. In the absence of adenosine, the aptamer can fold into a hairpin structure and form a cleavable double-stranded region. Fc is capable of being removed from electrode surface by treatment with endonuclease, and almost no peak current is observed. The adenosine/aptamer binding induces the conformational transition of designed aptamer, dissociating the cleavable double-stranded segment. Therefore, the integrated aptamer sequence is maintained when exposing to endonuclease, generating a peak current of Fc. Utilizing the present sensing scheme, adenosine even at a low concentration can give a detectable current signal. Thus, a detection limit of 10(-10) M and a linear response range from 3.74×10(-9) to 3.74×10(-5) M are achieved. The proposed proof-of-principle of a novel electrochemical sensing is expected to extend to establish various aptameric platforms for the analysis of a broad range of target molecules of interest.
Nucleic Acids Research 11/2010; 38(20):e185. · 8.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Gold nanoparticles (GNPs) possessing strong distance-dependent optical properties and high extinction coefficients have emerged as important colorimetric materials. Almost all colorimetric studies are based on two working mechanisms: sandwich cross-linking and non-cross-linking systems. In the present study, a new working mechanism, hairpin sticky-end pairing-induced GNP assembly, is introduced based on the discovery of unique aggregation behavior of aptamer-functionalized GNPs. The salt-induced aggregation of oligonucleotide probe-modified GNPs can readily occur due to the sticky-end pairing effect while addition of target molecules favors the formation of the hairpin structure of probe sequences and substantially inhibits the nanoparticle assembly. Along this line, we developed a proof-of-concept colorimetric homogeneous assay using immunoglobulin E (IgE) as an analyte model via transforming a commonly designed "light-down" colorimetric biosensor into a "light-up" one. From the point of view of both conformational transition of aptamer and steric bulk, oligonucleotide-GNPs display an additional stability upon binding to target molecules. The assay showed an extremely high sensitivity from both naked eye observations and absorbance measurements. Compared with almost all existing IgE sensing strategies, the proposed colorimetric system possesses a substantially improved analytical performance. Investigating the assembly behavior of hairpin aptamer-modified GNPs could offer new insight into the dependence of the GNP properties on the structure switching and open a new way to design signaling probes and develop colorimetric assay schemes.
Analytical Chemistry 05/2010; 82(9):3890-8. · 5.86 Impact Factor
