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ABSTRACT: A synergistic graphene oxide-gold nanoclusters (GO-AuNCs) hybrid has been constructed as enzyme mimic that is able to show high catalytic activity over a broad pH range, especially at neutral pH. Importantly, the target-functionalized hybrid has been applied as a robust nanoprobe for selective, quantitative, and fast colorimetric detection of cancer cells.
Advanced Materials 02/2013; · 13.88 Impact Factor
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ABSTRACT: Bladder cancer (BC) and kidney cancer (KC) are the first two commonly occurring genitourinary cancers in China. In this study, a comprehensive LC-MS-based method, which utilizes both reversed phase liquid chromatography (RPLC) and hydrophilic interaction chromatography (HILIC) separations, has been carried out in conjunction with multivariate data analysis to discriminate the global serum profiles of BC, KC, and noncancer controls. An independent test set consisting of different patients has been used to objectively evaluate the predictive ability of the analysis platform. Excellent sensitivity and specificity have been achieved in detection of KC and BC. The results suggest that serum metabolic profiling could be used for different types of genitourinary cancer diagnosis. Furthermore, cancer type-specific biomarkers were found through a critical selection criterion. As a result, eicosatrienol, azaprostanoic acid, docosatrienol, retinol, and 14'-apo-beta-carotenal were found as specific biomarkers for BC; and PE(P-16:0e/0:0), glycerophosphorylcholine, ganglioside GM3 (d18:1/22:1), C17 sphinganine, and SM(d18:0/16:1(9Z)) were found as specific biomarkers for KC. Receiver operating characteristic (ROC) analysis was used for the preliminary evaluation of the biomarkers. These biomarkers have great potential to be used in the clinical diagnosis after further rigorous assessment.
Proteomics 06/2012; 12(14):2238-46. · 4.43 Impact Factor
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ABSTRACT: A new strategy to create site-specific, homogeneous, and bright silver nanoclusters (AgNCs) with high-stability was demonstrated by triplex DNA as template. By reasonable design of DNA sequence, homogeneous Ag(2) cluster was obtained in the predefined position of CG.C(+) site of triplex DNA. This strategy was also explored for controlled alignment of AgNCs on the DNA nanoscaffold. To the best of our knowledge, this was the first example to simultaneously answer the challenges of excellent site-specific nucleation and growth, homogeneity and stability against salt of DNA-templated AgNCs.
Nucleic Acids Research 05/2012; 40(16):e122. · 8.03 Impact Factor
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ABSTRACT: In this study, we develop an efficient method for multiple DNA detection by exploring silver nanoclusters (AgNCs)-graphene oxide (GO) nanohybrid materials. Because of the extraordinarily high quenching efficiency of GO, the ssDNA-AgNCs probe exhibits minimal background fluorescence, while strong emission is observed when it forms a double helix with the specific target DNA, leading to a high signal-to-background ratio. Therefore the AgNCs-GO nanohybrid materials can be successfully applied for DNA detection. The system described here exhibits not only high sensitivity with a detection limit of 1 nM, but also an excellent differentiation ability for single-base mismatched sequences. In addition, by exploring AgNCs as signal reporters and GO as the nanoquencher, this approach avoids labeling the probe DNA or target DNA, which offers the advantages of simplicity and cost efficiency. Moreover, the large planar surface of GO allows adsorption of different DNA-AgNCs probes, each with a distinct emission, leading to a multicolor sensor for the detection of multiple DNA targets in the same solution.
The Analyst 04/2012; 137(11):2588-92. · 4.23 Impact Factor
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ABSTRACT: A DNA-encoding strategy is reported for the programmable regulation of the fluorescence properties of silver nanoclusters (AgNCs). By taking advantage of the DNA-encoding strategy, aqueous AgNCs were used as signal transducers to convert DNA inputs into fluorescence outputs for the construction of various DNA-based logic gates (AND, OR, INHIBIT, XOR, NOR, XNOR, NAND, and a sequential logic gate). Moreover, a biomolecular keypad that was capable of constructing crossword puzzles was also fabricated. These AgNC-based logic systems showed several advantages, including a simple transducer-introduction strategy, universal design, and biocompatible operation. In addition, this proof of concept opens the door to a new generation of signal transducer materials and provides a general route to versatile biomolecular logic devices for practical applications.
Chemistry 04/2012; 18(21):6663-9. · 5.93 Impact Factor
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ABSTRACT: Molecule-like silver nanoclusters (AgNCs) with few to tens of atoms are highly sensitive to the sequence and structure of DNA stabilizers. In this paper, a novel pH-triggered reversible molecular fluorescence switch is developed by taking advantage of the DNA-dependent fluorescence pH response of AgNCs. The DNA-AgNCs fluorescence switch simultaneously addresses concerns of simple construction strategy, efficient design and organic-solvent-free operation. Moreover, the excellent photostability and biocompatibility of AgNCs provide great potential for application of the DNA-AgNCs fluorescence switch in the development of functional molecular devices. Specifically, we apply the DNA-AgNCs fluorescence switch combined with the DNA sequence-dependent pH response pattern of AgNCs for construction of molecular logic gates.
Molecular BioSystems 03/2012; 8(3):921-6. · 3.53 Impact Factor
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ABSTRACT: An easy prepared fluorescence turn-on and colorimetric dual channel probe was developed for rapid assay of Hg(2+) ions with high sensitivity and selectivity by using poly(acrylic acid)-templated silver nanoclusters (PAA-AgNCs). The PAA-AgNCs exhibited weak fluorescence, while upon the addition of Hg(2+) ions, AgNCs gives a dramatic increase in fluorescence as a result of the changes of the AgNCs states. The detection limit was estimated to be 2 nM, which is much lower than the Hg(2+) detection requirement for drinking water of U.S. Environmental Protection Agency, and the turn-on sensing mode offers additional advantage to efficiently reduce background noise. Also, a colorimetric assay of Hg(2+) ions can be realized due to the observed absorbance changes of the AgNCs. More importantly, the method was successfully applied to the determination of Hg(2+) ions in real water samples, which suggests our proposed method has a great potential of application in environmental monitoring.
Talanta 01/2012; 88:290-4. · 3.79 Impact Factor
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ABSTRACT: In this work, unmodified carbon nanodots are demonstrated as novel and environmentally-friendly fluorescence probes for the sensing of Hg(2+) and biothiols with high sensitivity and selectivity.
Chemical Communications 12/2011; 48(8):1147-9. · 6.17 Impact Factor
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ABSTRACT: The purpose of this study was to use metabonomic profiling to identify a potential specific biomarker pattern in urine as a noninvasive bladder cancer (BC) detection strategy. A liquid chromatography-mass spectrometry based method, which utilized both reversed phase liquid chromatography and hydrophilic interaction chromatography separations, was performed, followed by multivariate data analysis to discriminate the global urine profiles of 27 BC patients and 32 healthy controls. Data from both columns were combined, and this combination proved to be effective and reliable for partial least squares-discriminant analysis. Following a critical selection criterion, several metabolites showing significant differences in expression levels were detected. Receiver operating characteristic analysis was used for the evaluation of potential biomarkers. Carnitine C9:1 and component I, were combined as a biomarker pattern, with a sensitivity and specificity up to 92.6% and 96.9%, respectively, for all patients and 90.5% and 96.9%, respectively for low-grade BC patients. Metabolic pathways of component I and carnitine C9:1 are discussed. These results indicate that metabonomics is a practicable tool for BC diagnosis given its high efficacy and economization. The combined biomarker pattern showed better performance than single metabolite in discriminating bladder cancer patients, especially low-grade BC patients, from healthy controls.
Molecular & Cellular Proteomics 07/2011; 10(10):M111.007922. · 7.40 Impact Factor
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Chemistry 07/2011; 17(28):7745-9. · 5.93 Impact Factor
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ABSTRACT: We demonstrate a novel concept for the construction of a label-free, quadruplex-based functional molecular beacon (LFG4-MB) by using G-quadruplex motif as a substitute for Watson-Crick base pairing in the MB stem and a specific G-quadruplex binder, N-methyl mesoporphyrin IX (NMM) as a reporter. It shows high sensitivity in assays for UDG activity/inhibition and detection of DNA sequence based on the unique fluorescence increase that occurs as a result of the strong interaction between NMM and the folded quadruplex upon removal of uracil by UDG or displacement of block sequence by target DNA. The LFG4-MB is simple in design, fast in operation and could be easily transposed to other biological relevant target analysis by simply changing the recognition portion. The LFG4-MB does not require any chemical modification for DNA, which offers the advantages of simplicity and cost efficiency and obviates the possible interference with the affinity and specificity of the MB as well as the kinetic behavior of the catalysts caused by the bulky fluorescent groups. More importantly, the LFG4-MB offers great extent of freedom to tune the experimental conditions for the general applicability in bioanalysis.
Chemistry 02/2011; 17(5):1635-41. · 5.93 Impact Factor
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ABSTRACT: Precise organization of metallic nanoclusters on DNA scaffolds holds great interest for nanopatterned materials that may find uses in electronics, sensors, medicine, and many other fields. Herein, we report the site-specific growth of fluorescent silver nanoclusters by using a mismatched double-stranded DNA template. Few-atom, molecular-scale Ag clusters are found to localize at the mismatched site and the metallized DNA retains its integrity. The DNA-encapsulated nanoclusters can be utilized as functional biological probes to identify single-nucleotide polymorphisms by taking advantage of the very bright fluorescence and excellent photostability of the nanoclusters. This approach offers the possibility of constructing novel DNA-based nanomaterials and nanomechanical devices with more sophisticated functions and will be highly beneficial in future biochemical, pharmaceutical, nanomechanical, and electronic applications.
Chemistry 02/2011; 17(13):3774-80. · 5.93 Impact Factor
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ABSTRACT: A LC-MS based method, which utilizes both reversed-performance (RP) chromatography and hydrophilic interaction chromatography (HILIC) separations, has been carried out in conjunction with multivariate data analysis to discriminate the global serum profiles of renal cell carcinoma (RCC) patients and healthy controls. The HILIC was found necessary for a comprehensive serum metabonomic profiling as well as RP separation. The feasibility of using serum metabonomics for the diagnosis and staging of RCC has been evaluated. One-hundred percent sensitivity in detection has been achieved, and a satisfactory clustering between the early stage and advanced-stage patients is observed. The results suggest that the combination of LC-MS analysis with multivariate statistical analysis can be used for RCC diagnosis and has potential in the staging of RCC. The MS/MS experiments have been carried out to identify the biomarker patterns that made great contribution to the discrimination. As a result, 30 potential biomarkers for RCC are identified. It is possible that the current biomarker patterns are not unique to RCC but just the result of any malignancy disease. To further elucidate the pathophysiology of RCC, related metabolic pathways have been studied. RCC is found to be closely related to disturbed phospholipid catabolism, sphingolipid metabolism, phenylalanine metabolism, tryptophan metabolism, fatty acid beta-oxidation, cholesterol metabolism, and arachidonic acid metabolism.
Journal of Proteome Research 02/2011; 10(3):1396-405. · 5.11 Impact Factor
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ABSTRACT: A novel proton-fueled molecular gate-like delivery system has been constructed for controlled cargo release using i-motif quadruplex DNA as caps onto pore outlets of mesoporous silica nanoparticles. Start from simple conformation changes, the i-motif DNA cap can open and close the pore system in smart response to pH stimulus. Importantly, the opening/closing and delivery protocol is highly reversible and a partial cargo delivery can be easily controlled at will. A pH-switchable nanoreactor has also been developed to validate the potential of our system for on-demand molecular transport. This proof of concept might open the door to a new generation of carrier materials and could also provide a general route to use other functional nucleic acids/peptide nucleic acids as capping agents in the fields of versatile controlled delivery nanodevices.
Nucleic Acids Research 10/2010; 39(4):1638-44. · 8.03 Impact Factor
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ABSTRACT: A conceptually new class of telomere DNA/conjugated polymer system has been constructed to enable sensing of pH changes and create robust logic gates capable of multiplex logic operations. It combines the advantages of quadruplex-duplex conversion and efficient energy transfer from the polymer to the DNA binding molecule. The system is simple in design, fast in operation, and allows the detection of pH changes with high accuracy and sensitivity. In addition, the approach could be adopted for the investigation of other biomolecular conformational changes upon binding to their targets. More importantly, the present logic operations showed advantages over other nucleic acid-based logic gates: (1) The system does not require any CP modification or oligonucleotide labeling, which offers the advantages of simplicity and cost efficiency. (2) The reversibility of the switch makes the logic gates feasible to realize system reset. (3) The system could be implemented to perform multiple logic functions by using distinct input signals.
Molecular BioSystems 10/2010; 6(10):1928-32. · 3.53 Impact Factor
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ABSTRACT: A new type of rapid, highly sensitive, and selective fluorescence turn-on assay for detection of cysteine and histidine using a DNA/ligand/ion ensemble is developed. This assay is based on the highly specific interaction between the amino acids and the metal ions and the strong fluorescence thiazole orange (TO)/DNA probe in a competition assay format. The resulting high sensitivity and selectivity for cysteine and histidine was achieved by changing the metal ions. The system is simple in design and fast in operation and is more convenient and promising than other methods. The novel strategy eliminated the need of organic cosolvents, enzymatic reactions, separation processes, chemical modifications, and sophisticated instrumentations. The detection and discrimination process can be seen with the naked eye under a hand-held UV lamp and can be easily adapted to automated high-throughput screening. The detection limit of this method is lower than or at least comparable to previous fluorescence-based methods. The dynamic range of the sensor can be tuned simply by adjusting the concentration of metal ions. Importantly, the protocol offers high selectivity for the determination of cysteine among amino acids found in proteins and in serum samples. The assay shows great potential for practical application as a disease-associated biomarker and will be needed to satisfy the great demand of amino acid determination in fields such as food processing, biochemistry, pharmaceuticals, and clinical analysis.
Analytical Chemistry 10/2010; 82(19):8211-6. · 5.86 Impact Factor
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Advanced Materials 07/2010; 22(25):2792-8. · 13.88 Impact Factor
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ABSTRACT: We demonstrate a unique quadruplex-based fluorescence assay for sensitive, facile, real-time, and label-free detection of RNase H activity and inhibition by using a G-quadruplex formation strategy. In our approach, a RNA-DNA substrate was prepared, with the DNA strand designed as a quadruplex-forming oligomer. Upon cleavage of the RNA strand by RNase H, the released G-rich DNA strand folds into a quadruplex in the presence of monovalent ions and interacts with a specific G-quadruplex binder, N-methyl mesoporphyrin IX (NMM); this gives a dramatic increase in fluorescence and serves as a reporter of the reaction. This novel assay is simple in design, fast in operation, and is more convenient and promising than other methods. It takes less than 30 min to finish and the detection limit is much better or at least comparable to previous reports. No sophisticated experimental techniques or chemical modification for either RNA or DNA are required. The assay can be accomplished by using a common spectrophotometer and obviates possible interference with the kinetic behavior of the catalysts. Our approach offers an ideal system for high-throughput screening of enzyme inhibitors and demonstrates that the structure of the G-quadruplex can be used as a functional tool in specific fields in the future.
Chemistry 02/2010; 16(8):2605-10. · 5.93 Impact Factor
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ABSTRACT: We have demonstrated a smart polymeric transducer and aptamer/intercalating dye system that allows the label-free detection of protein with high sensitivity and selectivity.
Chemical Communications 12/2009; · 6.17 Impact Factor
