15 research outputs found

    Homogeneous and Sensitive Detection of microRNA with Ligase Chain Reaction and Lambda Exonuclease-Assisted Cationic Conjugated Polymer Biosensing

    No full text
    A simple and homogeneous microRNA assay is developed by integration of ligase chain reaction (LCR) and lambda exonuclease-assisted cationic conjugated polymer (CCP) biosensing. LCR is utilized for exponential amplification of microRNA, and lambda exonuclease is introduced to degrade excess fluorescein-labeled probes in LCR for eliminating background signal. After addition of CCP, efficient fluorescence resonance energy transfer from CCP to fluorescein in LCR products occurs. The method is sensitive enough to detect 0.1 fM target microRNA and specific to discriminate one-base difference of microRNAs, which paves a new way for homogeneous microRNA detection and molecular diagnosis

    Conjugated Polymers/DNA Hybrid Materials for Protein Inactivation

    No full text
    Chromophore-assisted light inactivation (CALI) is a powerful tool for analyzing protein functions due to the high degree of spatial and temporal resolution. In this work, we demonstrate a CALI approach based on conjugated polymers (CPs)/DNA hybrid material for protein inactivation. The target protein is conjugated with single-stranded DNA in advance. Single-stranded DNA can form CPs/DNA hybrid material with cationic CPs via electrostatic and hydrophobic interactions. Through the formation of CPs/DNA hybrid material, the target protein that is conjugated with DNA is brought into close proximity to CPs. Under irradiation, CPs harvest light and generate reactive oxygen species (ROS), resulting in the inactivation of the adjacent target protein. This approach can efficiently inactivate any target protein which is conjugated with DNA and has good specificity and universality, providing a new strategy for studies of protein function and adjustment of protein activity

    Conjugated Polymers Act Synergistically with Antibiotics to Combat Bacterial Drug Resistance

    No full text
    The emergence of drug-resistant bacteria severely challenges the antimicrobial agents and antibacterial strategy. Here, we demonstrate a novel, simple, and highly efficient combination therapy strategy by direct combinations of cationic conjugated polymers (CCPs) with polypeptide antibiotics against Gram-negative and Gram-positive bacteria based on a synergistic antibacterial effect. The combination therapy method enhances the antibacterial efficacy with a significantly reduced antibiotic dosage. Also, the highly efficient and synergistic killing of drug-resistant bacteria is realized. Using combinations of CCPs and antibiotics to show increased antibacterial activity, this strategy will provide a much wider scope of the discovery of efficient antibacterial systems than that of antibiotic–antibiotic combinations. The proposed combination therapy method provides a universal and powerful platform for the treatment of pathogens, in particular, the drug-resistant bacteria, and also opens a new way for the development of efficient antibacterial systems

    Evidence of Intermediate Hydrogen States in the Formation of a Complex Hydride

    No full text
    A complex hydride (LaMg<sub>2</sub>NiH<sub>7</sub>) composed of La<sup>3+</sup>, two Mg<sup>2+</sup>, [NiH<sub>4</sub>]<sup>4–</sup> with a covalently bonded hydrogen, and three H<sup>–</sup> was formed from an intermetallic LaMg<sub>2</sub>Ni via an intermediate phase (LaMg<sub>2</sub>NiH<sub>4.6</sub>) composed of La, Mg, NiH<sub>2</sub>, NiH<sub>3</sub> units, and H atoms at tetrahedral sites. The NiH<sub>2</sub> and NiH<sub>3</sub> units in LaMg<sub>2</sub>NiH<sub>4.6</sub> were reported as precursors for [NiH<sub>4</sub>]<sup>4–</sup> in LaMg<sub>2</sub>NiH<sub>7</sub> [Miwa et al. J. Phys. Chem. C 2016, 120, 5926–5931]. To further understand the hydrogen states in the precursors (the NiH<sub>2</sub> and NiH<sub>3</sub> units) and H atoms at the tetrahedral sites in the intermediate phase, LaMg<sub>2</sub>NiH<sub>4.6</sub>, we observed the hydrogen vibrations in LaMg<sub>2</sub>NiH<sub>4.6</sub> and LaMg<sub>2</sub>NiH<sub>7</sub> by using inelastic neutron scattering. A comparison of the hydrogen vibrations of the NiH<sub>2</sub> and NiH<sub>3</sub> units with that of [NiH<sub>4</sub>]<sup>4–</sup> shows that the librational modes of the NiH<sub>2</sub> and NiH<sub>3</sub> units were nonexistent; librational modes are characteristic modes for complex anions, such as [NiH<sub>4</sub>]<sup>4–</sup>. Furthermore, the hydrogen vibrations for the H atoms in the tetrahedral sites showed a narrower wavenumber range than that for H<sup>–</sup> and a wider range than that for typical interstitial hydrogen. The results indicated the presence of intermediate hydrogen states before the formation of [NiH<sub>4</sub>]<sup>4–</sup> and H<sup>–</sup>

    Visual Detection of Multiplex MicroRNAs Using Cationic Conjugated Polymer Materials

    No full text
    A simple, visual, and specific method for simultaneous detection of multiplex microRNAs (miRNAs) has been developed by integrating duplex-specific nuclease (DSN)-induced amplification with cationic conjugated polymer (CCP) materials. The probe DNA with a complementary sequence to target miRNA is labeled with fluorescein dye (FAM). Without target miRNA, the single-strand DNA probe cannot be digested by DSN. Upon adding CCPs, efficient fluorescence resonance energy transfer (FRET) from CCP to FAM occurs owing to strong electrostatic interactions between CCP and the DNA probe. In the presence of target miRNA, the DNA probe hybridizes with target miRNA followed by digestion to small nucleotide fragments by DSN; meanwhile, the miRNA is released and subsequently interacts again with the probe, resulting in the cycled digestion of the DNA probe. In this case, weak electrostatic interactions between oligonucleotide fragments and CCP lead to inefficient FRET from CCP to FAM. Thus, by triggering the FRET signal from CCP to FAM, miRNA can be specially detected, and the fluorescence color change based on FRET can be visualized directly with the naked eye under an UV lamp. Furthermore, an energy transfer cascade can be designed using CCP and DNA probes labeled at the 5′-terminus with FAM and Cy3 dyes, and the multistep FRET processes offer the ability of simultaneous detection of multiplex miRNAs

    Au-WO<sub>3</sub> Nanowire-Based Electrodes for NO<sub>2</sub> Sensing

    No full text
    In this work, a selective and highly sensitive gas sensor using tungsten oxide (WO3) nanofibers was fabricated via electrospinning. WO3 was functionalized with gold nanoparticles by magnetron sputtering at different sputtering times to obtain Au films with thicknesses of 1, 5, 10, and 15 nm. The sensing performance of Au film composite nanomaterials with different Au layer thicknesses was tested at 100–250 °C and different nitrogen dioxide (NO2) concentrations ranging from 200 to 1000 ppb. The findings showed that the 10 nm Au–WO3 composite nanomaterial sensor had the most significant improvement in the performance of the pristine WO3 sensor compared with other Au–WO3 composite nanomaterial sensors, and the optimal operating temperature of the sensor was 175 °C. The composite nanomaterial sensor exhibited excellent selectivity when exposed to different gases and also exhibited high sensibility when exposed to low concentrations of NO2 under high humidity (80%). The mechanism of gas sensor performance improvement was also investigated

    Chemical Bonding and Transport Properties in Clathrates‑I with Cu–Zn–P Frameworks

    No full text
    Quaternary clathrate-I phases with an overall composition of Ba<sub>8</sub><i>M</i><sub>16+y</sub>P<sub>30‑y</sub> (M = Cu,Zn) exhibit complex structural chemistry. Characterization of the electronic structures and chemical bonding using quantum-chemical calculations and <sup>31</sup>P solid state NMR spectroscopy demonstrated that the Cu–Zn–P framework is flexible and able to accommodate up to six Zn atoms per formula unit via bonding rearrangements, such as partial Zn/P substitution and the formation of Cu–Zn bonds. Such perturbations of the framework’s bonding affect the thermal and charge transport properties. The overall thermoelectric figure-of-merit, <i>ZT</i>, of Ba<sub>8</sub>Cu<sub>14</sub>Zn<sub>2</sub>P<sub>30</sub> is 0.62 at 800 K, which is 9 times higher than the thermoelectric performance of the ternary parent phase Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub>. Through a combination of inelastic neutron scattering and single crystal X-ray diffraction experiments at 10 K, low-energy rattling of the Ba guest atoms inside the large tetrakaidecahedral cages are shown to be the reason for the low thermal conductivities observed for the studied clathrates

    Chemical Bonding and Transport Properties in Clathrates‑I with Cu–Zn–P Frameworks

    No full text
    Quaternary clathrate-I phases with an overall composition of Ba<sub>8</sub><i>M</i><sub>16+y</sub>P<sub>30‑y</sub> (M = Cu,Zn) exhibit complex structural chemistry. Characterization of the electronic structures and chemical bonding using quantum-chemical calculations and <sup>31</sup>P solid state NMR spectroscopy demonstrated that the Cu–Zn–P framework is flexible and able to accommodate up to six Zn atoms per formula unit via bonding rearrangements, such as partial Zn/P substitution and the formation of Cu–Zn bonds. Such perturbations of the framework’s bonding affect the thermal and charge transport properties. The overall thermoelectric figure-of-merit, <i>ZT</i>, of Ba<sub>8</sub>Cu<sub>14</sub>Zn<sub>2</sub>P<sub>30</sub> is 0.62 at 800 K, which is 9 times higher than the thermoelectric performance of the ternary parent phase Ba<sub>8</sub>Cu<sub>16</sub>P<sub>30</sub>. Through a combination of inelastic neutron scattering and single crystal X-ray diffraction experiments at 10 K, low-energy rattling of the Ba guest atoms inside the large tetrakaidecahedral cages are shown to be the reason for the low thermal conductivities observed for the studied clathrates

    Influence of Surface Oxidation on Ion Dynamics and Capacitance in Porous and Nonporous Carbon Electrodes

    No full text
    We investigate the influence of surface chemistry and ion confinement on capacitance and electrosorption dynamics of room-temperature ionic liquids (RTILs) in supercapacitors. Using air oxidation and vacuum annealing, we produced defunctionalized and oxygen-rich surfaces of carbide-derived carbons (CDCs) and graphene nanoplatelets (GNPs). While oxidized surfaces of porous CDCs improve capacitance and rate handling abilities of ions, defunctionalized nonporous GNPs improve charge storage densities on planar electrodes. Quasi-elastic neutron scattering (QENS) and inelastic neutron scattering (INS) probed the structure, dynamics, and orientation of RTIL ions confined in divergently functionalized pores. Oxidized, ionophilic surfaces draw ions closer to pore surfaces and enhance potential-driven ion transport during electrosorption. Molecular dynamics (MD) simulations corroborated experimental data and demonstrated the significance of surface functional groups on ion orientations, accumulation densities, and capacitance

    Interfacial Stability of Li Metal–Solid Electrolyte Elucidated via in Situ Electron Microscopy

    No full text
    Despite their different chemistries, novel energy-storage systems, e.g., Li–air, Li–S, all-solid-state Li batteries, etc., face one critical challenge of forming a conductive and stable interface between Li metal and a solid electrolyte. An accurate understanding of the formation mechanism and the exact structure and chemistry of the rarely existing benign interfaces, such as the Li–cubic-Li<sub>7–3<i>x</i></sub>Al<sub><i>x</i></sub>La<sub>3</sub>Zr<sub>2</sub>O<sub>12</sub> (c-LLZO) interface, is crucial for enabling the use of Li metal anodes. Due to spatial confinement and structural and chemical complications, current investigations are largely limited to theoretical calculations. Here, through an in situ formation of Li–c-LLZO interfaces inside an aberration-corrected scanning transmission electron microscope, we successfully reveal the interfacial chemical and structural progression. Upon contact with Li metal, the LLZO surface is reduced, which is accompanied by the simultaneous implantation of Li<sup>+</sup>, resulting in a tetragonal-like LLZO interphase that stabilizes at an extremely small thickness of around five unit cells. This interphase effectively prevented further interfacial reactions without compromising the ionic conductivity. Although the cubic-to-tetragonal transition is typically undesired during LLZO synthesis, the similar structural change was found to be the likely key to the observed benign interface. These insights provide a new perspective for designing Li–solid electrolyte interfaces that can enable the use of Li metal anodes in next-generation batteries
    corecore