Rong Hu

Hunan University, Ch’ang-sha-shih, Hunan, China

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Publications (15)97.9 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Fluorescent sensing systems based on the quenching of fluorophores have found wide applications in bioassays. An efficient quencher will endow the sensing system a high sensitivity. The frequently used quenchers are based on organic molecules or nanomaterials, which usually need tedious synthesizing and modifying steps, and exhibit different quenching efficiencies to different fluorophores. In this work, we for the first time report that aggregated perylene derivative can serve as a broad-spectrum and label-free quencher that is able to efficiently quench a variety of fluorophores, such as green, red and far red dyes labeled on DNA. By choosing nucleases as model biomolecules, such a broad-spectrum quencher was then employed to construct a multiplexed bioassay platform through a label-free manner. Due to the high quenching efficiency of the aggregated perylene, the proposed platform could detect nuclease with high sensitivity, with a detection limit of 0.03 U/mL for EcoRV, and 0.05 U/mL for EcoRI. The perylene quencher does not affect the activity of nuclease, which makes it possible to design post-addition type bioassay platform. Moreover, the proposed platform allows simultaneous and multicolor analysis of nucleases in homogeneous solution, demonstrating its value of potential application in rapid screening of multiple bio-targets.
    Biosensors & bioelectronics 01/2014; 58:320–325. · 5.43 Impact Factor
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    ABSTRACT: DNA nanotechnology has been extensively explored to assemble various functional nanostructures for versatile applications. Mediated by Watson-Crick base-pairing, these DNA nanostructures have been conventionally assembled through hybridization of many short DNA building blocks. Here we report the noncanonical self-assembly of multifunctional DNA nanostructures, termed as nanoflowers (NFs), and the versatile biomedical applications. These NFs were assembled from long DNA building blocks generated via rolling circle replication (RCR) of a designer template. NF assembly was driven by liquid crystallization and dense packaging of building blocks, without relying on Watson-Crick base-pairing between DNA strands, thereby avoiding the otherwise conventional complicated DNA sequence design. NF sizes were readily tunable in a wide range, by simply adjusting such parameters as assembly time and template sequences. NFs were exceptionally resistant to nuclease degradation, denaturation, or dissociation at extremely low concentration, presumably resulting from the dense DNA packaging in NFs. The exceptional biostability is critical for biomedical applications. By rational design, NFs can be readily incorporated with myriad functional moieties. All these properties make NFs promising for versatile applications. As a proof-of-principle demonstration, in this study, NFs were integrated with aptamers, bioimaging agents, and drug loading sites, and the resultant multifunctional NFs were demonstrated for selective cancer cell recognition, bioimaging, and targeted anticancer drug delivery.
    Journal of the American Chemical Society 10/2013; · 10.68 Impact Factor
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    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; · 6.38 Impact Factor
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    ABSTRACT: DNA nanotrain: Anchoring of preformed fluorescent DNA nanodevices (NDs; see picture) and in situ self-assembly of fluorescent DNA NDs on target living cell surfaces are reported. The in situ self-assembly of the nanodevice was further shown on surfaces of living cells in cell mixtures. These DNA NDs exhibited fluorescence emission and underwent fluorescence resonance energy transfer (FRET) on living cell surfaces.
    Angewandte Chemie International Edition 04/2013; · 13.73 Impact Factor
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    ABSTRACT: Gold nanoparticles-based colorimetric assay possesses several unique advantages, and has been applied for a wide range of targets, varying from nucleic acids to different metal ions. However, due to the lack of proper coordinating ligand, gold nanoparticles-based colorimetric sensing system for Au(3+) has not been developed so far. It is well-known that Au(3+) could induce the oxidation transition of thiol compounds to disulfide compounds. In this article, for the first time we converted such thiol masking reaction into colorimetric sensing system for label-free detection of Au(3+) via a target-controlled aggregation of nanoparticles strategy. In the new proposed sensing system, fluorosurfactant-capped gold nanoparticles were chosen as signal reporter units, while an Au(3+)-triggered oxidation of cysteine (Cys), which inhibited the aggregation of gold nanoparticles, acted as the recognition unit. By varying the amount of Cys, a tunable response range accompanied with different windows of color change could be obtained for Au(3+), illustrating the universality of the sensing system for Au(3+) samples with different sensitivity requirements. Under optimized condition, the proposed sensing system exhibits a high sensitivity towards Au(3+) with a detection limit of 50nM, which is lower than previously reported spectroscopic methods. It has also been applied for detection of Au(3+) in practical water samples with satisfactory result.
    Biosensors & bioelectronics 04/2013; 48C:1-5. · 5.43 Impact Factor
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    ABSTRACT: A new and facile strategy using double-stranded DNA-copper nanoparticles (dsDNA-Cu NPs) as fluorescence reporters for the highly sensitive and selective detection of l-histidine was demonstrated. In the dsDNA-Cu NPs-based sensing system, the fluorescence was quenched considerably upon the addition of l-histidine. Under the optimized experimental conditions, the probe exhibits excellent performance (e.g., a satisfactory detection limit of 5μM and high specificity). Our in situ method requires no covalent attachment of DNA to a fluorophore, which could significantly reduce the cost and simplify the procedure for l-histidine detection. Moreover, the proposed sensing system could be applicable for the detection of target biomolecule in complex biological samples. These striking properties make it an attractive platform for the direct detection of l-histidine.
    Talanta 03/2013; 107C:402-407. · 3.50 Impact Factor
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    ABSTRACT: DNAzymes have been widely applied as signal amplifiers for enzyme-free and highly sensitive detection of DNA. A few of them have also been employed for amplified detection of other biomolecules via a target-triggered assembly of split or mutated DNAzyme strategy. However, most of these designs adopt Mg2+-dependent DNAzyme as catalytic unit, which suffered from low catalytic cleavage activity. Meanwhile, some DNAzymes with high catalytic activity are not suitable for these designs because the slight modification of the catalytic core might results in remarkably decreased or even no catalytic activity of these DNAzymes. Based on DNAzyme topological effect or the terminal protection of small-molecule-linked DNA, we developed two versatile sensing platforms for amplified detection of different biotargets. Since no modification is necessary for the catalytic core of the DNAzyme in these designs, they can employ any DNAzyme with high catalytic activity as amplified unit, which affords a high amplified efficiency for the sensing platform. A catalytic and molecular beacon design was further employed to realize the true enzymatic multiple turnover of DNAzyme. These designs together allow a high sensitivity for the biotargets, resulting in a detection limit of 20 pM, 0.2 U/mL and 1 ng/mL for target DNA, DNA adenine methylation methyltransferase (Dam MTase) and streptavidin, respectively, much lower than previously reported biosensors. In addition, the proposed sensing strategy is versatile. By conjugating with various recognition units, it can be employed to detect a wide range of biotargets, varying from nucleic acids to proteins with high sensitivity.
    Analytical Chemistry 02/2013; · 5.70 Impact Factor
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    ABSTRACT: The double-strand DNA (dsDNA) can act as an efficient template for the formation of copper nanoparticles (Cu NPs) with high fluorescence, whereas the single-strand DNA (ssDNA) cannot support the formation of Cu NPs. This difference in fluorescent signal generation can be used for the detection of nuclease cleavage activity. Thus, a label-free strategy for sensitive detection of nuclease has been developed. The sensor contains a complete complementary dsDNA which acts as a template for the formation of Cu NPs and generation of fluorescence signal. The enzyme S1 nuclease was taken as the model analyte. Upon addition of S1 nuclease into the sensing system, the DNA was cleaved into fragments, preventing the formation of the Cu NPs and resulting in low fluorescence. In order to achieve the system's best sensing performance, a series of experimental conditions were optimized. Under the optimized experimental conditions, the sensor exhibits excellent performance (e.g., a detection limit of 0.3UmL(-1) with high selectivity). This possibly makes it an attractive platform for the detection of S1 nuclease and other biomolecules.
    Biosensors & bioelectronics 10/2012; 42C:31-35. · 5.43 Impact Factor
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    ABSTRACT: A universal sensing platform for fluorescence turn-on detection of biomolecules is developed based on Fenton reaction triggered molecular beacon cleavage. Due to its high quenching efficiency, molecular beacons (MBs)-based sensing systems usually show low background fluorescence and large signal-to-background ratio. Glucose is chosen as a model biomolecule for constructing an MB-based fluorescence sensing system. In the presence of glucose, the glucose oxidase will bind with it and catalyze the oxidation to generate H(2)O(2), which is further decomposed to produce ()OH through the Fe(2+)-catalyzed Fenton reaction. Then, in-situ-generated OH can trigger the cleavage of the MB, and its fluorescence intensity will be dramatically increased because of the complete separation of the fluorophore from the quencher. By employing molecular beacon as both recognition and reporter probes to low background signal, the proposed biosensors showed high sensitivity to targets. It also exhibited high selectivity owing to the high specificity of the enzymatic oxidation, which make it valuable for the detection of target biomolecule in complex biological samples.
    Biosensors & bioelectronics 09/2012; · 5.43 Impact Factor
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    ABSTRACT: A proximity-dependent surface hybridization strategy is employed for designing a "signal-on" electrochemical DNAzyme biosensor. By taking advantage of the high sensitivity of the PDSH strategy, and by realizing the enzymatic hydrolysis reaction in a homogenous system with a unimolecular design, the proposed biosensor shows a very high sensitivity to target molecules.
    Chemical Communications 08/2012; 48(76):9507-9. · 6.38 Impact Factor
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    ABSTRACT: Nanomaterials possess several useful properties, including large surface-to-volume ratio, high biocompatibility, facile surface modification and overall structural robustness. They also have unique optical, magnetic and electronic properties. Nucleic acids, whether designed or selected in vitro, play important roles in biological assays and clinical diagnostics. In addition to nucleic acidprobe-based nucleotide complementarity, aptamers, which can bind with high affinity and specificity to a wide range of target molecules, comprise a new class of nucleic acids selected in vitro. The coupling of nucleic acids, including aptamers, with various nanomaterials provides special opportunities for developing novel biosensing systems with advanced and powerful functions. This review summarizes recent achievements in the design of nucleic acid-functionalized nanomaterials for bioimaging applications, especially carbon nanomaterials, gold nanoparticles, semiconductor nanoparticles, magnetic nanoparticles, and polyacrylamidenanoparticles. Because DNA is easier to synthesize and more stable than RNA, this review mainly focuses on the bioimaging applications of DNA-functionalized nanomaterials.
    Journal of Materials Chemistry 10/2011; 21(41):16323-16334. · 5.97 Impact Factor
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    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. · 3.50 Impact Factor
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    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. · 6.38 Impact Factor
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    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. · 8.28 Impact Factor
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    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. · 5.70 Impact Factor