JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
FeP Nanoparticles Film Grown on Carbon Cloth: An Ultrahighly Active 3D Hydrogen Evolution Cathode in Both Acidic and Neutral Solutions.
ACS Appl Mater Interfaces
PUBLISHED: 11-18-2014
Show Abstract
Hide Abstract
In this Letter, we demonstrate the direct growth of FeP nanoparticles film on carbon cloth (FeP/CC) through low-temperature phosphidation of its Fe3O4/CC precursor. Remarkably, when used as an integrated 3D hydrogen evolution cathode, this FeP/CC electrode exhibits ultrahigh catalytic activity comparable to commercial Pt/C and good stability in acidic media. This electrode also performs well in neutral solutions. This work offers us the most cost-effective and active 3D cathode toward electrochemical water splitting for large-scale hydrogen fuel production.
Related JoVE Video
Holey graphene nanosheets: large-scale rapid preparation and their application toward highly-effective water cleaning.
Nanoscale
PUBLISHED: 08-27-2014
Show Abstract
Hide Abstract
In this communication, we demonstrate the rapid large-scale preparation of holey graphene nanosheets (h-G NSs) via low-temperature thermal treatment of oxidized graphite powder obtained by a modified Brodie method in air. The h-G NSs have nanopores with a high specific surface area and large pore volume. When used as a water cleaning agent, they exhibit excellent absorption performances for oils, solvents and dyes.
Related JoVE Video
Graphitic carbon nitride nanosheets: one-step, high-yield synthesis and application for Cu2+ detection.
Analyst
PUBLISHED: 08-20-2014
Show Abstract
Hide Abstract
In this article we report on the one-step, rapid, high-yield synthesis of graphitic carbon nitride (g-C3N4) nanosheets for the first time. The nanosheets were obtained by pyrolyzing a melamine-KBH4 mixture under Ar. As a fluorosensor for Cu(2+), the g-C3N4 nanosheets exhibit a detection limit as low as 0.5 nM and high selectivity in buffer solutions, and this sensor was applied to the analysis of lake water samples. The electrogenerated chemiluminescence (ECL) behavior of the g-C3N4 nanosheets using Na2S2O8 as the coreactant was also studied. Results suggest that the ECL intensity of the g-C3N4 nanosheets was linear over concentrations of 0-45 nM, with a detection limit of 1.2 nM for Cu(2+).
Related JoVE Video
A Cost-Effective 3D Hydrogen Evolution Cathode with High Catalytic Activity: FeP Nanowire Array as the Active Phase.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 07-03-2014
Show Abstract
Hide Abstract
Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]-hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale-up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its ?-FeOOH NA/Ti precursor through a low-temperature phosphidation reaction. When applied as self-supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127?mV to afford current densities of 10 and 100?mA?cm(2) , respectively. The excellent electrocatalytic performance is promising for applications as non-noble-metal HER catalyst with a high performance-price ratio in electrochemical water splitting for large-scale hydrogen fuel production.
Related JoVE Video
Self-supported nanoporous cobalt phosphide nanowire arrays: an efficient 3D hydrogen-evolving cathode over the wide range of pH 0-14.
J. Am. Chem. Soc.
PUBLISHED: 05-15-2014
Show Abstract
Hide Abstract
In this Communication, we report the topotactic fabrication of self-supported nanoporous cobalt phosphide nanowire arrays on carbon cloth (CoP/CC) via low-temperature phosphidation of the corresponding Co(OH)F/CC precursor. The CoP/CC, as a robust integrated 3D hydrogen-evolving cathode, shows a low onset overpotential of 38 mV and a small Tafel slope of 51 mV dec(-1), and it maintains its catalytic activity for at least 80,00 s in acidic media. It needs overpotentials (?) of 67, 100, and 204 mV to attain current densities of 10, 20, and 100 mA cm(-2), respectively. Additionally, this electrode offers excellent catalytic performance and durability under neutral and basic conditions.
Related JoVE Video
Carbon nanotubes decorated with CoP nanocrystals: a highly active non-noble-metal nanohybrid electrocatalyst for hydrogen evolution.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 04-10-2014
Show Abstract
Hide Abstract
The development of effective and inexpensive hydrogen evolution reaction (HER) electrocatalysts for future renewable energy systems is highly desired. The strongly acidic conditions in proton exchange membranes create a need for acid-stable HER catalysts. A nanohybrid that consists of carbon nanotubes decorated with CoP nanocrystals (CoP/CNT) was prepared by the low-temperature phosphidation of a Co3O4/CNT precursor. As a novel non-noble-metal HER catalyst operating in acidic electrolytes, the nanohybrid exhibits an onset overpotential of as low as 40?mV, a Tafel slope of 54?mV?dec(-1), an exchange current density of 0.13?mA?cm(-2), and a Faradaic efficiency of nearly 100?%. This catalyst maintains its catalytic activity for at least 18?hours and only requires overpotentials of 70 and 122?mV to attain current densities of 2 and 10?mA?cm(-2), respectively.
Related JoVE Video
Self-supported Cu3P nanowire arrays as an integrated high-performance three-dimensional cathode for generating hydrogen from water.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 03-31-2014
Show Abstract
Hide Abstract
Searching for inexpensive hydrogen evolution reaction (HER) electrocatalysts with high activity has attracted considerable research interest in the past years. Reported herein is the topotactic fabrication of self-supported Cu3 P nanowire arrays on commercial porous copper foam (Cu3 P NW/CF) from its Cu(OH)2 NW/CF precursor by a low-temperature phosphidation reaction. Remarkably, as an integrated three-dimensional hydrogen-evolving cathode operating in acidic electrolytes, Cu3 P NW/CF maintains its activity for at least 25?hours and exhibits an onset overpotential of 62?mV, a Tafel slope of 67?mV?dec(-1) , and a Faradaic efficiency close to 100?%. Catalytic current density can approach 10?mA?cm(-2) at an overpotential of 143?mV.
Related JoVE Video
Ultrathin graphitic C3 N4 nanosheets/graphene composites: efficient organic electrocatalyst for oxygen evolution reaction.
ChemSusChem
PUBLISHED: 02-27-2014
Show Abstract
Hide Abstract
Graphitic C3 N4 (g-C3 N4 ) is used as a low-cost organic oxygen evolution reaction (OER) electrocatalyst. The integration of ultrathin g-C3 N4 nanosheets with graphene leads to g-C3 N4 /graphene composites with high OER activity and good durability. X-ray photoelectron spectroscopy (XPS) studies suggest that the OER activity results from pyridinic-N-related active sites. This catalyst provides an alternative to OER catalysts based on transition metals.
Related JoVE Video
Primary paraganglioma located between the thyroid gland and the left common carotid artery: A case report.
Oncol Lett
PUBLISHED: 01-30-2014
Show Abstract
Hide Abstract
Head and neck paraganglioma is a rare and predominantly asymptomatic tumor. In the present study, an extremely rare case of asymptomatic paraganglioma located between the left common carotid artery and the left thyroid is described. The clinical presentation, cytomorphology and the immunohistochemical characteristics for the diagnosis of head and neck paraganglioma are described. To the best of our knowledge, only two cases of paraganglioma located between the left common carotid artery and the left thyroid have previously been reported.
Related JoVE Video
Ultrathin graphitic carbon nitride nanosheets: a novel peroxidase mimetic, Fe doping-mediated catalytic performance enhancement and application to rapid, highly sensitive optical detection of glucose.
Nanoscale
PUBLISHED: 10-15-2013
Show Abstract
Hide Abstract
In this article, we demonstrate for the first time that ultrathin graphitic carbon nitride nanosheets (g-C3N4) possess peroxidase activity. Fe doping of the nanosheets leads to peroxidase mimetics with greatly enhanced catalytic performance and the mechanism involved is proposed. We further demonstrate the novel use of such Fe-g-C3N4 as a cheap nanosensor for simple, rapid, highly selective and sensitive optical detection of glucose with a pretty low detection limit of 0.5 ?M.
Related JoVE Video
Spinel CuCo2O4 nanoparticles supported on N-doped reduced graphene oxide: a highly active and stable hybrid electrocatalyst for the oxygen reduction reaction.
Langmuir
PUBLISHED: 10-15-2013
Show Abstract
Hide Abstract
In this Letter, for the first time, we demonstrated the preparation of a highly efficient electrocatalyst, spinel CuCo2O4 nanoparticles supported on N-doped reduced graphene oxide (CuCo2O4/N-rGO), for an oxygen reduction reaction (ORR) under alkaline media. The hybrid exhibits higher ORR catalytic activity than CuCo2O4 or N-rGO alone, the physical mixture of CuCo2O4 nanoparticles and N-rGO, and Co3O4/N-rGO. Moreover, such a hybrid affords superior durability to the commercial Pt/C catalyst.
Related JoVE Video
Ultrathin graphitic carbon nitride nanosheets: a low-cost, green, and highly efficient electrocatalyst toward the reduction of hydrogen peroxide and its glucose biosensing application.
Nanoscale
PUBLISHED: 08-12-2013
Show Abstract
Hide Abstract
In this communication, we demonstrate for the first time that ultrathin graphitic carbon nitride (g-C?N?) nanosheets can serve as a low-cost, green, and highly efficient electrocatalyst toward the reduction of hydrogen peroxide. We further demonstrate its application for electrochemical glucose biosensing in both buffer solution and human serum medium with a detection limit of 11 ?M and 45 ?M, respectively.
Related JoVE Video
Two-dimensional hybrid mesoporous Fe2O3-graphene nanostructures: a highly active and reusable peroxidase mimetic toward rapid, highly sensitive optical detection of glucose.
Biosens Bioelectron
PUBLISHED: 08-07-2013
Show Abstract
Hide Abstract
In this article, for the first time, two-dimensional hybrid mesoporous Fe2O3-graphene (mFe2O3-G) nanostructures were developed as a peroxidase mimetic with catalytic activities superior to those of mFe2O3, G, and previously reported Fe-based peroxidase mimetics. The high-surface-area mFe2O3 not only offers a large number of catalytically active sites, but also facilitates the diffusion of 3,3,5,5-tetramethylbenzidine (TMB) and H2O2 toward G surface. On the other hand, G is ?-rich and thus favors the adsorption and enrichment of TMB within these pores. These synergistic effects lead to highly improved catalytic performances. Based on these findings, a simple, rapid, and highly sensitive and selective optical detector of glucose has been developed and demonstrated in buffer solution with a pretty low detection limit of 0.5 ?M. In addition, this nanosensor is reusable and can also be used for glucose detection in diluted serum.
Related JoVE Video
Au-nanoparticle-loaded graphitic carbon nitride nanosheets: green photocatalytic synthesis and application toward the degradation of organic pollutants.
ACS Appl Mater Interfaces
PUBLISHED: 07-22-2013
Show Abstract
Hide Abstract
Au nanoparticles (AuNPs) were loaded on graphitic carbon nitride (g-C3N4) nanosheets prepared by ultrasonication-assisted liquid exfoliation of bulk g-C3N4 via green photoreduction of Au(III) under visible light irradiation using g-C3N4 as an effective photocatalyst. The nanohybrids show superior photocatalytic activities for the decomposition of methyl orange under visible-light irradiation to bulk g-C3N4, g-C3N4 nanosheets, and AuNP/bulk g-C3N4 hybrids.
Related JoVE Video
Ultrathin graphitic carbon nitride nanosheet: a highly efficient fluorosensor for rapid, ultrasensitive detection of Cu(2+).
Anal. Chem.
PUBLISHED: 05-17-2013
Show Abstract
Hide Abstract
A highly efficient fluorosensor based on ultrathin graphitic carbon nitride (g-C?N?) nanosheets for Cu(2+) was developed. In the absence of metal ions, the nanosheets exhibit high fluorescence; the strong coordination of the Lewis basic sites on them to metal ions, however, causes fluorescence quenching via photoinduced electron transfer leading to the qualitative and semiquantitative detection of metal ions. This fluorosensor exhibits high selectivity toward Cu(2+). The whole detection process can be completed within 10 min with a detection limit as low as 0.5 nM. The use of test paper enables the naked-eye detection of Cu(2+) with a detection limit of 0.1 nmol. The practical use of this sensor for Cu(2+) determination in real water samples was also demonstrated.
Related JoVE Video
Production of stable aqueous dispersion of poly(3,4-ethylenedioxythiophene) nanorods using graphene oxide as a stabilizing agent and their application for nitrite detection.
Analyst
PUBLISHED: 10-06-2011
Show Abstract
Hide Abstract
A stable aqueous dispersion of poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods stabilized by graphene oxide (GO) has been successfully prepared via interface polymerization of EDOT in the presence of GO for the first time. The non-covalent functionalization of PEDOT by GO leads to a PEDOT-GO dispersion that can be stable for several days without the observation of any floating or precipitated particles. Several analytical techniques including Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to characterize the resultant PEDOT-GO nanocomposites. It is found that such PEDOT-GO nanocomposites exhibit good catalytic activity toward the oxidation of nitrite, leading to a sensor for detection of nitrite. The linear detection range and detection limit are estimated to be 4 ?M to 2.48 mM (r = 0.999), and 1.2 ?M at a signal-to-noise ratio of 3, respectively.
Related JoVE Video
Iron-substituted SBA-15 microparticles: a peroxidase-like catalyst for H2O2 detection.
Analyst
PUBLISHED: 09-30-2011
Show Abstract
Hide Abstract
In this communication, we demonstrate our recent finding that iron-substituted SBA-15 (Fe-SBA-15) microparticles possess intrinsic peroxidase-like activity and can catalyze the oxidation of peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) by H(2)O(2) to develop a blue color in aqueous solution, leading to a simple approach towards colorimetric detection of H(2)O(2) with a linear detection range from 0.4 ?M to 15 ?M (r = 0.997) and a detection limit of 0.2 ?M.
Related JoVE Video
Electrodeposition-based construction of random arrays of Pt nanoparticles on glassy carbon electrode (GCE) towards methanol oxidation application.
J Nanosci Nanotechnol
PUBLISHED: 07-26-2011
Show Abstract
Hide Abstract
An eletrodeposition of random arrays of Pt nanoparticles, supported on glassy carbon electrode (GCE), is reported. It has been shown that such arrays exhibited good catalytic activity with respect to methanol oxidation in an acidic medium and longer deposition time produced more Pt nanoparticles on GCE leading to larger effective catalytic area and higher catalytic current. It was found that the process of methanol oxidation was controlled by the diffusion of methanol and the Pt nanoparticles formed stable film on GCE surface and also exhibited stable catalytic performance towards methanol oxidation.
Related JoVE Video
A new preparation of Au nanoplates and their application for glucose sensing.
Biosens Bioelectron
PUBLISHED: 05-27-2011
Show Abstract
Hide Abstract
The present communication demonstrates a relatively green preparative route toward Au nanoplates in aqueous solution at room temperature with the use of tannic acid (TA), which is an environmentally friendly, soluble polyphenol, as a reducing agent. Such Au nanoplates exhibit notable catalytic performance toward the oxidation and reduction of H(2)O(2). A glucose biosensor was further fabricated by immobilizing glucose oxidase (GOD) into chitosan-Au nanoplate composites film on the surface of glassy carbon electrode (GCE). This sensor exhibits good response to glucose, and the linear response range is estimated to be from 2 to 20 mM (R=0.999) at 0.65 V and from 2 to 10 mM (R=0.993) at -0.2 V, respectively. The sensitivity of the sensor determined from the slopes is 49.5 ?A mM(-1)cm(-2) at 0.65 V.
Related JoVE Video
Aniline as a dispersing and stabilizing agent for reduced graphene oxide and its subsequent decoration with Ag nanoparticles for enzymeless hydrogen peroxide detection.
J Colloid Interface Sci
PUBLISHED: 04-25-2011
Show Abstract
Hide Abstract
An aqueous dispersion of reduced graphene oxide (rGO) has been successfully prepared via chemical reduction of graphene oxide (GO) by hydrazine hydrate in the presence of aniline for the first time. The noncovalent functionalization of rGO by aniline leads to a rGO dispersion that can be very stable for several months without the observation of any floating or precipitated particles. Several analytical techniques including Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) have been used to characterize the resulting rGO. Taking advantages of the fact reducing ability of aniline toward AgNO(3), we further demonstrated the subsequent decoration of rGO with Ag nanoparticles (AgNPs) by in situ chemical reduction of silver salts. It was found that such AgNP/rGO nanocomposites exhibit good catalytic activity toward the reduction of hydrogen peroxide (H(2)O(2)), leading to an enzymeless sensor with a fast amperometric response time of less than 2s. The linear detection range is estimated to be from 100 ?M to 80 mM (r=0.9991), and the detection limit is estimated to be 7.1 ?M at a signal-to-noise ratio of 3.
Related JoVE Video
A novel single fluorophore-labeled double-stranded oligonucleotide probe for fluorescence-enhanced nucleic acid detection based on the inherent quenching ability of deoxyguanosine bases and competitive strand-displacement reaction.
J Fluoresc
PUBLISHED: 04-13-2011
Show Abstract
Hide Abstract
We develop a novel single fluorophore-labeled double-stranded oligonucleotide (OND) probe for rapid, nanostructure-free, fluorescence-enhanced nucleic acid detection for the first time. We further demonstrate such probe is able to well discriminate single-base mutation in nucleic acid. The design takes advantage of an inherent quenching ability of guanine bases. The short strand of the probe is designed with an end-labeled fluorophore that is placed adjacent to two guanines as the quencher located on the long opposite strand, resulting in great quenching of dye fluorescence. In the presence of a target complementary to the long strand of the probe, a competitive strand-displacement reaction occurs and the long strand forms a more stable duplex with the target, resulting in the two strands of the probe being separated from each other. As a consequence of this displacement, the fluorophore and the quencher are no longer in close proximity and dye fluorescence increases, signaling the presence of target.
Related JoVE Video
Poly(2,3-diaminonaphthalene) microspheres as a novel quencher for fluorescence-enhanced nucleic acid detection.
Analyst
PUBLISHED: 03-31-2011
Show Abstract
Hide Abstract
In this Communication, we report on the first preparation of conjugation polymer poly(2,3-diaminonaphthalene) (PDAN) microspheres via chemical oxidation polymerization of 2,3-diaminonaphthalene (DAN) monomers by ammonium persulfate (APS) at room temperature. We further demonstrate the use of PDAN microspheres as a novel quencher for fluorescence-enhanced nucleic acid detection.
Related JoVE Video
Titanium silicalite-1 zeolite microparticles for enzymeless H2O2 detection.
Analyst
PUBLISHED: 03-24-2011
Show Abstract
Hide Abstract
In this communication, we demonstrate for the first time that titanium silicalite-1 zeolite microparticles (TSZMs) can effectively catalyze the reduction of H(2)O(2), leading to an enzymeless H(2)O(2) sensor with a linear detection range from 100 ?M to 40 mM (r = 0.994) and a detection limit of 0.5 ?M at a signal-to-noise ratio of 3.
Related JoVE Video
Fluorescence-enhanced potassium ions detection based on inherent quenching ability of deoxyguanosines and K(+)-induced conformational transition of G-rich ssDNA from duplex to G-quadruplex structures.
J Fluoresc
PUBLISHED: 03-23-2011
Show Abstract
Hide Abstract
Herein, we develop a novel single fluorophore-labeled double-stranded oligonucleotide (OND) probe for rapid fluorescence-enhanced K(+) detection, based on an inherent quenching ability of guanine bases and G-rich OND conformation transition from duplex to G-quadruplex. This probe presents high sensitivity and good selectivity for the detection of K(+), and the assay process is simple and fast.
Related JoVE Video
Carbon nanoparticle for highly sensitive and selective fluorescent detection of mercury(II) ion in aqueous solution.
Biosens Bioelectron
PUBLISHED: 03-19-2011
Show Abstract
Hide Abstract
In this article, carbon nanoparticles (CNPs) were used as a novel fluorescent sensing platform for highly sensitive and selective Hg(2+) detection. To the best of our knowledge, this is the first example of CNPs obtained from candle soot used in this type of sensor. The general concept used in this approach is based on that adsorption of the fluorescently labeled single-stranded DNA (ssDNA) probe by CNP via ?-? stacking interactions between DNA bases and CNP leads to substantial dye fluorescence quenching; however, in the presence of Hg(2+), T-Hg(2+)-T induced hairpin structure does not adsorb on CNP and thus retains the dye fluorescence. A detection limit as low as 10nM was achieved. The present CNP-based biosensor for Hg(2+) detection exhibits remarkable specificity against other possible metal ions. Furthermore, superior selectivity performance was observed when Hg(2+) detection was carried out in the presence of a large amount of other interference ions. Finally, in order to evaluate its potential practical application, Hg(2+) detection was conducted with the use of lake water other than pure buffer and it is believed that it holds great promise for real sample analysis upon further development.
Related JoVE Video
Preparation of Ag nanoparticle-decorated poly(m-phenylenediamine) microparticles and their application for hydrogen peroxide detection.
Analyst
PUBLISHED: 03-08-2011
Show Abstract
Hide Abstract
The chemical oxidation polymerization of m-phenylenediamine (MPD) by ammonium persulfate (APS) at room temperature results in the formation of poly(m-phenylenediamine) (PMPD) microparticles. The subsequent treatment of such microparticles with an aqueous AgNO(3) solution produces Ag nanoparticle (AgNP)-decorated PMPD microparticles. It was found that as-formed AgNPs exhibited remarkable catalytic performance toward the reduction of hydrogen peroxide (H(2)O(2)). The enzymeless H(2)O(2) sensor constructed with such composites showed a fast amperometric response time of less than 5 s, and the corresponding linear range and detection limit were estimated to be from 0.1 to 30 mM and 4.7 µM, respectively, at a signal-to-noise ratio of 3.
Related JoVE Video
Self-assembled graphene platelet-glucose oxidase nanostructures for glucose biosensing.
Biosens Bioelectron
PUBLISHED: 03-04-2011
Show Abstract
Hide Abstract
Graphene platelet-glucose oxidase (GP-GOD) nanostructures have been prepared through self-assembly of GOD and chitosan (CS) functionalized GPs by electrostatic attraction in aqueous solution. The stable aqueous dispersion of GPs was prepared by chemical reduction of graphene oxide with the use of CS as a reducing and stabilizing agent. UV-vis spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the resulting GPs and GP-GOD nanostructures. Furthermore, a glucose biosensor was constructed by deposition of the resultant GP-GOD on the surface of glassy carbon electrode. It was found that the resulting biosensor exhibits good response to glucose. The linear detection range is estimated to be from 2 to 22 mM (r=0.9987), and the detection limit is estimated to be 20 ?M at a signal-to-noise ratio of 3.
Related JoVE Video
Coordination polymer nanobelts as an effective sensing platform for fluorescence-enhanced nucleic acid detection.
Macromol Rapid Commun
PUBLISHED: 02-23-2011
Show Abstract
Hide Abstract
In this communication, the application of coordination polymer nanobelts (CPNs) assembled from H(2)PtCl(6) and 3,3,5,5-tetramethylbenzidine (TMB) are explored as an effective fluorescent sensing platform for nucleic acid detection for the first time. The suggested method has a high selectivity down to single-base mismatch. DNA detection is accomplished by the following two steps: (1) CPN binds fluorecent dye-labeled single-stranded DNA (ssDNA) probe via both electrostatic attraction and ?-? stacking interactions between unpaired DNA bases and CPN. As a result, the fluorescent dye is brought into close proximity to CPN and substantial fluorescence quenching occurs due to photoinduced electron transfer from the nitrogen atom in CPN to the excited fluorophore. (2) The hybridization of adsorbed ssDNA probe with its target generates a double stranded DNA (dsDNA). The duplex cannot be adsorbed by CPN due to its rigid conformation and the absence of unpaired DNA bases, leading to an obvious fluorescence enhancement.
Related JoVE Video
Poly(m-phenylenediamine) nanospheres and nanorods: selective synthesis and their application for multiplex nucleic acid detection.
PLoS ONE
PUBLISHED: 02-14-2011
Show Abstract
Hide Abstract
In this paper, we demonstrate for the first time that poly(m-phenylenediamine) (PMPD) nanospheres and nanorods can be selectively synthesized via chemical oxidation polymerization of m-phenylenediamine (MPD) monomers using ammonium persulfate (APS) as an oxidant at room temperature. It suggests that the pH value plays a critical role in controlling the the morphology of the nanostructures and fast polymerization rate favors the anisotropic growth of PMPD under homogeneous nucleation condition. We further demonstrate that such PMPD nanostructures can be used as an effective fluorescent sensing platform for multiplex nucleic acid detection. A detection limit as low as 50 pM and a high selectivity down to single-base mismatch could be achieved. The fluorescence quenching is attributed to photoinduced electron transfer from nitrogen atom in PMPD to excited fluorophore. Most importantly, the successful use of this sensing platform in human blood serum system is also demonstrated.
Related JoVE Video
Ag@poly(m-phenylenediamine) core-shell nanoparticles for highly selective, multiplex nucleic acid detection.
Langmuir
PUBLISHED: 02-08-2011
Show Abstract
Hide Abstract
In this letter, we report on the one-step synthesis of Ag@poly(m-phenylenediamine) core-shell nanoparticles (APCSNPs), carried out by direct mixing of aqueous silver nitrate and m-phenylenediamine solutions at room temperature. We further demonstrate the use of APCSNP as a novel fluorescent sensing platform for nucleic acid detection. In this regard, the detection of DNA is accomplished in two steps. First, APCSNP absorbs and quenches the fluorescence of dye-labeled single-stranded DNA (ssDNA) as a probe. Second, hybridizing of the probe with its target produces a double-stranded DNA (dsDNA) that detaches from APCSNP, resulting in the recovery of dye fluorescence. It suggests that this sensing system has a high selectivity down to single-base mismatch, and the results exhibit good reproducibility. Furthermore, we also demonstrate its application for the multiplex detection of nucleic acid sequences.
Related JoVE Video
Organic solvent-induced controllable crystallization of the inorganic salt Na3[Au(SO3)2] into ultralong nanobelts and hierarchical microstructures of nanowires.
Nanoscale
PUBLISHED: 01-31-2011
Show Abstract
Hide Abstract
The present paper reports an organic solvent-induced controllable crystallization of a water-soluble inorganic salt Na(3)[Au(SO(3))(2)] into ultralong nanobelts and hierarchical microstructures of one-dimensional (1D) nanowires. It was found that the morphology of the resulting crystals can be fine tuned by simply varying the experimental parameters, such as the ratios of water to organic solvent and gold salt to organic solvent, as well as the type of organic solvent.
Related JoVE Video
Polyaniline nanofibres for fluorescent nucleic acid detection.
Nanoscale
PUBLISHED: 01-13-2011
Show Abstract
Hide Abstract
In this communication, we demonstrate for the first time that conducting polymer polyaniline (PANI) nanofibres can serve as a novel fluorescent sensing platform for nucleic acid detection with a high selectivity down to single-base mismatch.
Related JoVE Video
Poly(o-phenylenediamine) colloid-quenched fluorescent oligonucleotide as a probe for fluorescence-enhanced nucleic acid detection.
Langmuir
PUBLISHED: 12-27-2010
Show Abstract
Hide Abstract
In this Letter, we demonstrate that chemical oxidation polymerization of o-phenylenediamine (OPD) by potassium bichromate at room temperature results in the formation of submicrometer-scale poly(o-phenylenediamine) (POPD) colloids. Such colloids can absorb and quench dye-labeled single-stranded DNA (ssDNA) very effectively. In the presence of a target, a hybridization event occurs, which produces a double-stranded DNA (dsDNA) that detaches from the POPD surface, leading to recovery of dye fluorescence. With the use of an oligonucleotide (OND) sequence associated with human immunodeficiency virus (HIV) as a model system, we demonstrate the proof of concept that POPD colloid-quenched fluorescent OND can be used as a probe for fluorescence-enhanced nucleic acid detection with selectivity down to single-base mismatch.
Related JoVE Video
Conjugation polymer nanobelts: a novel fluorescent sensing platform for nucleic acid detection.
Nucleic Acids Res.
PUBLISHED: 12-22-2010
Show Abstract
Hide Abstract
In this article, we report on the facile and rapid synthesis of conjugation polymer poly(p-phenylenediamine) nanobelts (PNs) via room temperature chemical oxidation polymerization of p-phenylenediamine monomers by ammonium persulfate in aqueous medium. We further demonstrate the proof-of-concept that PNs can be used as an effective fluorescent sensing platform for nucleic acid detection for the first time. The general concept used in this approach lies in the facts that the adsorption of the fluorescently labeled single-stranded DNA probe by PN leads to substantial fluorescence quenching, followed by specific hybridization with the complementary region of the target DNA sequence. This results in desorption of the hybridized complex from PN surface and subsequent recovery of fluorescence. We also show that the sensing platform described herein can be used for multiplexing detection of nucleic acid sequences.
Related JoVE Video
A novel single-labeled fluorescent oligonucleotide probe for silver(I) ion detection based on the inherent quenching ability of deoxyguanosines.
Analyst
PUBLISHED: 12-15-2010
Show Abstract
Hide Abstract
A novel single-labeled fluorescent oligonucleotide (OND) probe for the detection of nanomolar silver(I) ion in aqueous solution is developed based on the inherent quenching ability of deoxyguanosines. The formation of a hairpin structure of the OND-Ag(+) complex brings deoxyguanosines close to a dye, leading to a decreased fluorescence intensity of the dye owning to photoinduced electron transfer from the dye to deoxyguanosines.
Related JoVE Video
Nucleic acid detection using carbon nanoparticles as a fluorescent sensing platform.
Chem. Commun. (Camb.)
PUBLISHED: 11-15-2010
Show Abstract
Hide Abstract
In this communication, we demonstrate for the first time the proof of concept that carbon nanoparticles (CNPs) can be used as an effective fluorescent sensing platform for nucleic acid detection with selectivity down to single-base mismatch. The dye-labeled single-stranded DNA (ssDNA) probe is adsorbed onto the surface of the CNP via ?-? interaction, quenching the dye. In the target assay, a double-stranded DNA (dsDNA) hybrid forms, recovering dye fluorescence.
Related JoVE Video
Monodisperse, micrometer-scale, highly crystalline, nanotextured Ag dendrites: rapid, large-scale, wet-chemical synthesis and their application as SERS substrates.
ACS Appl Mater Interfaces
PUBLISHED: 10-15-2010
Show Abstract
Hide Abstract
In this letter, we report on our interesting finding that the direct mixing of aqueous AgNO(3) and NH(2)OH solutions at room temperature leads to rapid, high-yield production of monodisperse, micrometer-scale, highly crystalline, nanotextured Ag dendrites. The surface-enhanced Raman scattering (SERS) effect of these Ag dendrites was evaluated by using 4-aminothiophenol (p-ATP) as the Raman probe and the results demonstrate that they exhibit strong SERS effects.
Related JoVE Video
A novel single-labeled fluorescent oligonucleotide probe for mercury(II) ion detection: using the inherent quenching of deoxyguanosines.
J Fluoresc
PUBLISHED: 09-23-2010
Show Abstract
Hide Abstract
A novel single-labeled fluorescent oligonucleotide (OND) probe for the detection of nanomolar mercury(II) ion in aqueous solution is developed based on the inherent quenching of deoxyguanosines. The formation of hairpin structure of OND-Hg(2+) complex brings deoxyguanosines close to dye, resulting in decreased dye fluorescence due to photoinduced electron transfer from dye to deoxyguanosines.
Related JoVE Video
Supramolecular microfibrils of o-phenylenediamine dimers: oxidation-induced morphology change and the spontaneous formation of Ag nanoparticle decorated nanofibers.
Langmuir
PUBLISHED: 09-15-2010
Show Abstract
Hide Abstract
The direct mix of aqueous FeCl(3) and o-phenylenediamine (OPD) solutions at room temperature leads to supramolecular microfibrils of OPD dimers generated by the oxidation of OPD monomers by FeCl(3) (Sun, X.; Hagner, M. Langmuir 2007, 23, 10441). In this Letter, we report on our recent finding that the subsequent treatment of such microfibrils with a AgNO(3) aqueous solution transforms them into nanofibers decorated with spherical silver nanoparticles (AgNPs) with sizes in range of 5-20 nm. The possible formation mechanism involved is also discussed. It is interestingly found that as-formed AgNPs exhibit good catalytic activity toward the reduction of H(2)O(2), leading to an enzymeless sensor with a fast amperometric response time of less than 5 s. The linear detection range is estimated to be from 100 ?M to 80 mM (r = 0.998), and the detection limit is estimated to be 62 ?M at a signal-to-noise ratio of 3.
Related JoVE Video
Biomolecule-assisted, environmentally friendly, one-pot synthesis of CuS/reduced graphene oxide nanocomposites with enhanced photocatalytic performance.
Langmuir
Show Abstract
Hide Abstract
In this work, we develop a novel environmentally friendly strategy toward one-pot synthesis of CuS nanoparticle-decorated reduced graphene oxide (CuS/rGO) nanocomposites with the use of L-cysteine, an amino acid, as a reducing agent, sulfur donor, and linker to anchor CuS nanoparticles onto the surface of rGO sheets. Upon visible light illumination (? > 400 nm), the CuS/rGO nanocomposites show pronounced enhanced photocurrent response and improved photocatalytic activity in the degradation of methylene blue (MB) compared to pure CuS. This could be attributed to the efficient charge transport of rGO sheets and hence reduced recombination rate of excited carriers.
Related JoVE Video
Synthesis and study of plasmon-induced carrier behavior at Ag/TiO2 nanowires.
Chemistry
Show Abstract
Hide Abstract
Nanocomposites of Ag/TiO(2) nanowires with enhanced photoelectrochemical performance have been prepared by a facile solvothermal synthesis of TiO(2) nanowires and subsequent photoreduction of Ag(+) ions to Ag nanoparticles (AgNPs) on the TiO(2) nanowires. The as-prepared nanocomposites exhibited significantly improved cathodic photocurrent responses under visible-light illumination, which is attributed to the local electric field enhancement of plasmon resonance effect near the TiO(2) surface rather than by the direct transfer of charge between the two materials. The visible-light-driven photocatalytic performance of these nanocomposites in the degradation of methylene blue dye was also studied, and the observed improvement in photocatalytic activity is associated with the extended light absorption range and efficient charge separation due to surface plasmon resonance effect of AgNPs.
Related JoVE Video
Environmentally friendly, one-pot synthesis of Ag nanoparticle-decorated reduced graphene oxide composites and their application to photocurrent generation.
Inorg Chem
Show Abstract
Hide Abstract
In this paper, we develop an environmentally friendly, one-pot strategy toward rapid preparation of Ag nanoparticle-decorated reducd graphene oxide (AgNPs/rGO) composites by heating the mixture of GO and AgNO(3) aqueous solution in the presence of sodium hydroxide at 80 °C under stirring. The reaction was accomplished within a short period of 10 min without extra reducing agent. As-synthesized AgNPs/rGO composites have been successfully applied in photocurrent generation in the visible spectral region.
Related JoVE Video
Hydrothermal treatment of grass: a low-cost, green route to nitrogen-doped, carbon-rich, photoluminescent polymer nanodots as an effective fluorescent sensing platform for label-free detection of Cu(II) ions.
Adv. Mater. Weinheim
Show Abstract
Hide Abstract
Increasing reaction temperature produces photoluminescent polymer nanodots (PPNDs) with decreased particle size and increased quantum yield. Such PPNDs are used as an effective fluorescent sensing platform for label-free sensitive and selective detection of Cu(II) ions with a detection limit as low as 1 nM. This method is successfully applied to determine Cu(2+) in real water samples.
Related JoVE Video
Novel application of CoFe layered double hydroxide nanoplates for colorimetric detection of H(2)O(2) and glucose.
Analyst
Show Abstract
Hide Abstract
The present communication demonstrates the proof of concept of using CoFe layered double hydroxide (CoFe-LDHs) nanoplates as an effective peroxidase mimetic to catalyze the oxidation of peroxidase substrate 3,3,5,5-tetramethylbenzidine in the presence of H(2)O(2) to produce a blue solution. We further demonstrate successfully CoFe-LDHs nanoplate-based colorimetric assay to detect H(2)O(2) and glucose.
Related JoVE Video
Novel use of poly(3,4-ethylenedioxythiophene) nanoparticles for fluorescent nucleic acid detection.
ACS Comb Sci
Show Abstract
Hide Abstract
In this paper, we demonstrate the novel use of poly(3,4-ethylene dioxythiophene) (PEDOT) nanoparticle as a very effective fluorescent sensing platform for the detection of nucleic acid sequences. The principle of the assay lies in the fact that the adsorption of the fluorescently labeled single-stranded DNA (ssDNA) probe by PEDOT nanoparticle leads to substantial fluorescence quenching, followed by specific hybridization with the complementary region of the target DNA sequence. This results in desorption of the hybridized complex from PEDOT nanoparticle surface and subsequent recovery of fluorescence. A detection limit as low as 30 pM could be achieved in this sensing system. We also demonstrate its application for multiplexed detection of nucleic acid sequences. Furthermore, this sensing system can realize the detection of single-base mismatch even in multiplexed format. It is of importance to note that the successful use of this sensing platform in human blood serum system is also demonstrated.
Related JoVE Video
Rectangular coordination polymer nanoplates: large-scale, rapid synthesis and their application as a fluorescent sensing platform for DNA detection.
PLoS ONE
Show Abstract
Hide Abstract
In this paper, we report on the large-scale, rapid synthesis of uniform rectangular coordination polymer nanoplates (RCPNs) assembled from Cu(II) and 4,4-bipyridine for the first time. We further demonstrate that such RCPNs can be used as a very effective fluorescent sensing platform for multiple DNA detection with a detection limit as low as 30 pM and a high selectivity down to single-base mismatch. The DNA detection is accomplished by the following two steps: (1) RCPN binds dye-labeled single-stranded DNA (ssDNA) probe, which brings dye and RCPN into close proximity, leading to fluorescence quenching; (2) Specific hybridization of the probe with its target generates a double-stranded DNA (dsDNA) which detaches from RCPN, leading to fluorescence recovery. It suggests that this sensing system can well discriminate complementary and mismatched DNA sequences. The exact mechanism of fluorescence quenching involved is elucidated experimentally and its use in a human blood serum system is also demonstrated successfully.
Related JoVE Video
A 3D Porous Supramolecular Architecture from Ultrathin g-C3N4 Nanosheets and Reduced Graphene Oxide: Solution Self-Assembly Construction and Application as a Highly Efficient Metal-Free Electrocatalyst for Oxygen Reduction Reaction.
ACS Appl Mater Interfaces
Show Abstract
Hide Abstract
Direct mixing of aqueous dispersions of ultrathin g-C3N4 nanosheets and graphene oxide (GO) under ultrasonication leads to 3D porous supramolecular architecture. Photoreduction of GO yields conductive porous g-C3N4/rGO hybrid. The resulting 3D architecture possesses high surface area, multilevel porous structure, good electrical conductivity, efficient electron transport network, and fast charge transfer kinetics at g-C3N4/rGO interfaces, which facilitate the diffusion of O2, electrolyte, and electrons in the porous frameworks during oxygen reduction reaction (ORR). Ultrathin g-C3N4 nanosheet also causes effective electron tunneling through g-C3N4 barrier leading to rich electrode-electrolyte-gas three-phase boundaries and shortens electron diffusion distance from rGO to O2. As a novel ORR catalyst, such 3D hybrid exhibits remarkable catalytic performance, outperformed other g-C3N4/rGO composites, and excellent durability.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.