Heng Lu

Northeast Institute of Geography and Agroecology, Peping, Beijing, China

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Publications (18)25.99 Total impact

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    ABSTRACT: We successfully conduct the label-free and real-time detection of the interactions between epoxy groups and rabbit IgG and 5' CTT CAG GTC ATG AGC CTG AT 3' oligonucleotide, and between the hybridization of 5' CTT CAG GTC ATG AGC CTG AT 3' and its complementary 3' GAA GTC CAG TAC TCG GAC TA 5' oligonucleotide, by the oblique-incidence reflectivity difference (OI-RD) method. The dynamic curves of OI-RD signals, corresponding to the kinetic processes of biomolecular combination or hybridization, are acquired. In our case, the combination of epoxy groups with rabbit IgG and 5' CTT CAG GTC ATG AGC CTG AT 3' oligonucleotide need almost one and a half hours and about two hundred seconds, respectively; and the hybridization of the two oligonucleotides needs about five hundred seconds. The experimental results show that the OI-RD is a promising method for the real-time and label-free detection of biomolecular interactions.
    Chinese Physics B 01/2011; 20(1). · 1.15 Impact Factor
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    ABSTRACT: An enhanced nonlinear current–voltage behavior has been observed in Au nanoparticle dispersed CaCu3Ti4O12 composite films. The double Schottky barrier model is used to explain the enhanced nonlinearity in I–V curves. According to the energy-band model and fitting result, the nonlinearity in Au: CCTO film is mainly governed by thermionic emission in the reverse-biased Schottky barrier. This result not only supports the mechanism of double Schottky barrier in CCTO, but also indicates that the nonlinearity of current–voltage behavior could be improved in nanometal composite films, which has great significance for the resistance switching devices.
    Solid State Communications 01/2011; 151(19):1336-1339. · 1.53 Impact Factor
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    ABSTRACT: The specific binding between Cy5-labeled goat anti-mouse Immunoglobulin G (IgG) and mouse IgG with a concentration range from 625 to 104 µg ml − 1 has been detected successfully by the oblique-incidence reflectivity difference (OI-RD) method in each procedure of microarray fabrication. The experimental data prove that the OI-RD method can be employed not only to distinguish the different concentrations in label-free fashion but also to detect the antibody–antigen capture. In addition, the differential treatment of the OI-RD signals can decrease the negative influences of glass slide as the microarray upholder. Therefore the OI-RD technique has promising applications for the label-free and high-throughput detection of protein microarrays.
    Journal of optics 09/2010; 12(9):095301. · 1.99 Impact Factor
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    ABSTRACT: Hybridizations between labeled or label-free targets and corresponding 21-base oligonucleotide probes, concentrations of which range from 0.39 to 50 μ M , are detected by oblique-incidence reflectivity difference (OI-RD) method and fluorescence detection. The experimental results demonstrate that the OI-RD method can be utilized to not only distinguish whether the hybridization of oligonucleotides happened but also directly tell the different concentrations of the labeled and unlabeled oligonucleotides on the microarrays. The analysis with a classical three-layer model suggests that single-strand DNA tends to lie on epoxy-functionalized glass slide while the double-strand DNA prefers to have a tilted angle with respect to the slide in our experimental situation. The label-free detection of hybridization of oligonucleotides declares that OI-RD is a promising method for label-free and high-throughput detection of the biological microarrays.
    Journal of Applied Physics 04/2010; · 2.21 Impact Factor
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    ABSTRACT: Biological microarrays with different proteins and different protein concentrations are detected without external labeling by an oblique-incidence reflectivity difference (OIRD) technique. The initial experiment results reveal that the intensities of OIRD signals can distinguish the different proteins and concentrations of protein. The OIRD technique promises feasible applications to life sciences for label-free and high-throughput detection. Keywordsoblique-incidence reflectivity difference-protein microarray-label-free detection
    Science China: Physics, Mechanics and Astronomy 01/2010; 53(2):306-309. · 1.17 Impact Factor
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    ABSTRACT: Mouse-Immunoglobulin G (mouse-IgG) with different concentrations in a range from 1000 to 0.0128 μg/mL and a specific hybridization with goat anti-mouse IgG were detected successfully by using an oblique-incidence reflectivity difference (OI-RD) method. Two detection signals, consisting of an imaginary part (Im{Δp-Δs}) and a real part (Re{Δp-Δs}) of OI-RD, were obtained simultaneously. The detection results of hybridization by OI-RD were in accord with that of traditional fluorescent scans. In particular, we label-freely detected the washed mouse-IgG microarray with a series of concentrations and acquired a linear correlation between OI-RD intensities and the protein concentrations in logarithmic coordinates. The detection sensitivity of OI-RD can reach 14 fg. These experimental results suggest that the OI-RD method has potential applications in proteomics and clinical diagnosis.
    Science China: Physics, Mechanics and Astronomy 01/2010; 53(7):1230-1233. · 1.17 Impact Factor
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    ABSTRACT: A pyroelectric behavior was observed in CaCu3Ti4O12 films and the pyroelectric coefficient was measured to be 1.35×10−7 C/cm2 K for a film with thickness of 700 nm from 295 K to 340 K, larger than those of most pyroelectric materials. It was observed that the pyroelectric coefficient increased with the thickness of films from 300 to 700 nm. The origin of pyroelectric effect is proposed to depend on the distortion of the Ti–O octahedron due to the presence of Ti3+ ions. Comparing with the measurement result of an unpolarized film, our study strongly supports the interpretation of relaxor ferroelectric behavior in CaCu3Ti4O12.
    Applied Physics A 01/2010; 99(4):849-852. · 1.69 Impact Factor
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    ABSTRACT: We label-free detected the biological process of preparing a microarray that includes 400 spots of mouse immunoglobulin G (IgG) as well as the specific hybridization between mouse IgG and goat anti-mouse IgG by an oblique-incidence reflectivity difference (OI-RD) method. The detection results after each process including printing, washing, blocking, and hybridization, demonstrate that the OI-RD method can trace the preparation process of a microarray and detect the specific hybridization between antigens and antibodies. OI-RD is a promising method for label-free and high-throughput detection of biological microarrays.
    Chinese Physics Letters 01/2010; 27(10). · 0.92 Impact Factor
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    ABSTRACT: The Bi1.5Zn1.0Nb1.5O7 (BZN) thin film has been fabricated on MgO (001) substrate by pulsed laser deposition. The nonlinear optical properties of the BZN film were investigated using Z-scan technique at a wavelength of 532 nm with 25 ps pulse duration. The two-photon absorption coefficient and the nonlinear refractive index of the BZN film were obtained to be 4.2 × 10− 6 cm/W and 1.6 × 10− 10 cm2/W respectively, which are comparable with those of some representative nonlinear optical materials. The large and fast response optical nonlinearities indicated that the BZN film is a promising candidate for future photonics devices.
    Thin Solid Films 06/2009; 517(16):4626–4628. · 1.87 Impact Factor
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    ABSTRACT: Au:BaTiO(3) composite films comprising hexagon-shaped Au nanoparticle arrays covered with BaTiO(3) matrix were fabricated by double-layer nanosphere lithography and pulsed laser deposition technique. The optical nonlinearity of the composite film was determined using the Z-scan technique at a wavelength of 532 nm and a pulse duration of 25 ps. The third-order nonlinear optical susceptibility, chi(3), was found to be 2.9x10(-8) esu, which is comparable with the best values in metal-dielectric films comprising randomly distributed spherical particles but with much higher metal concentrations. The local electric field enhancement in and near the particles was investigated using the dipole discrete approximation method.
    Applied Optics 02/2009; 48(2):375-9. · 1.69 Impact Factor
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    ABSTRACT: CaCu3Ti4O12 (CCTO) thin films were successfully prepared on LaAlO3 substrates by pulsed laser deposition technique. We measured the nonlinear optical susceptibility of the thin films using Z-scan method at a wavelength of 532 nm with pulse durations of 25 ps and 7 ns. The large values of the third-order nonlinear optical susceptibility, χ (3), of the CCTO film were obtained to be 2.79×10−8 esu and 3.30×10−6 esu in picosecond and nanosecond time regimes, respectively, which are among the best results of some representative nonlinear optical materials. The origin of optical nonlinearity of CCTO films was discussed. The results indicate that the CCTO films on LaAlO3 substrates are promising candidate materials for applications in nonlinear optical devices.
    Applied Physics A 01/2009; 94(3). · 1.69 Impact Factor
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    ABSTRACT: a b s t r a c t The multilayer composite films consisting of multi-armed CdS nanorods and ZnO were fabricated by spin coating and pulsed laser deposition on fused quartz substrates. The nonlinear optical properties such as nonlinear refraction and absorption were determined using closed-and open-aperture Z-scan method with 532 nm picosecond and 800 nm femtosecond laser pulses, respectively. The nonlinear optical response time was studied by a time resolved Kerr-gate technique at 800 nm, showing an instantaneous process. The large optical nonlinearity with ultrafast response of the composite films indicated their potential applications for future nonlinear optical devices.
    01/2009; 67.
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    ABSTRACT: The multi-armed CdS nanorods were synthesized by aqueous chemical growth route at room temperature. The nonlinear optical properties of CdS nanorods dispersed in ethanol solution were investigated using the Z-scan method at a wavelength of 532nm with pulse duration of 25ps. The third-order nonlinear optical susceptibility, χ(3), was determined to be 1.6×10−13esu. Accounting for the CdS concentration and the effect of the dielectric confinement, χ(3) was extrapolated to be ∼10−9esu, which is over one order of magnitude larger than that of bulk material.
    Physica E Low-dimensional Systems and Nanostructures 01/2009; 41(4):715-717. · 1.52 Impact Factor
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    ABSTRACT: This paper reports that the detection to the protein in microarray format is carried out by oblique-incidence reflectivity difference (OI-RD) analysis without any labelling agents. The OI-RD intensities not only depend on the protein structure, but also vary with the protein concentration. The results indicate that this method should have potential application in detection of biochemical processes. The high throughout and in situ detection can be achieved by this method with further improving of the experimental system.
    Chinese Physics B 01/2008; 17(6):2288-2291. · 1.15 Impact Factor
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    ABSTRACT: In this study Oblique-Incidence Reflectivity Difference (OIRD) technique, a recent developed label-free detection, is applied to image biomolecular microarrays. Compared to the currently widely used fluorescence-dependent optical microscopy, OIRD technique not only images the morphology of protein bio-arrays in the absence of extrinsic labeling molecules but also monitors the changes in the optical properties of biochips in high-throughput fashion. Additionally, such a technique complements other label-free detections including Surface Plasmon Resonance (SPR) and Mass Spectrometry (MS) by offering the opportunity to detect biochemical activities without the special requirements on the substrate or the specific matrix medium. It is shown in this article that the surface topography can be reflected by OIRD method. Besides, the differences among printing concentrations and various proteins are able to be identified as well. Incidentally, the OIRD images appear to be useful aids to distinguish the variations resulting from antibody-antigen capture. Both the imaginary and real parts of OIRD images we presented provide more information than the single imaginary one especially. On the basis of the scattering mechanism, the absorptive properties of protein molecules are analyzed through the real part of OIRD signal. Accordingly, OIRD technique shows its unique potential in detection of biochemical processes.
    Proc SPIE 11/2007;
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    ABSTRACT: The triangular-shaped Au/ZnO nanoparticle arrays were fabricated on fused quartz substrate using nanosphere lithography. The structural characterization of the Au/ZnO nanoparticle arrays was investigated by atomic force microscopy. The absorption peak due to the surface plasmon resonance of Au particles at the wavelength of about 570 nm was observed. The nonlinear optical properties of the nanoparticle arrays were measured using the z-scan method at a wavelength of 532 nm with pulse duration of 10 ns. The real and imaginary part of third-order nonlinear optical susceptibility, Re x (3) and Im x (3) , were determined to be 1.15 Â 10 À6 and À5.36 Â 10 À7 esu, respectively. The results show that the Au/ ZnO nanoparticle arrays have great potential for future optical devices.
    Applied Surface Science 09/2007; 81. · 2.54 Impact Factor
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    ABSTRACT: The third-order optical nonlinearity of a composite film consisting of periodic triangular gold nanoparticle arrays coated with ZnO was investigated by the z-scan technique. The third-order nonlinear susceptibility, χ (3) , measured at a wavelength of 532 nm with a pulse duration of 10 ns, was up to 1.3 × 10 −5 esu. The figure of merit, χ 3 /α (where α is the absorption coefficient) was about 1.1 × 10 −9 esu cm. The large optical nonlinearity is likely due to the strong local electromagnetic field near the triangular gold particles and ZnO matrix. The results show that the composite film has great potential for nonlinear optical devices.
    Journal of Physics D Applied Physics 01/2007; 40:6705-6708. · 2.53 Impact Factor
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    ABSTRACT: The microarrays of 20-base oligonucleotide with different concentrations are detected before and after hybridization by the oblique-incidence reflectivity difference (OI-RD) method. The experimental results prove that OI-RD is a label-free method which can not only distinguish the concentration difference of oligonucleotides before and after the hybridization but also detect the hybridization of short oligonucleotides. At present the OI-RD method can detect 0.39 μmol/L 20-base oligonucleotide or less. These results suggest that the OI-RD method is a promising and potential technique for label-free detection of biological microarrays. Keywordsoblique-incidence reflectivity difference-microarray detection-label-free detection-oligonucleotides microarray
    Science China: Physics, Mechanics and Astronomy 53(8):1434-1437. · 1.17 Impact Factor

Publication Stats

52 Citations
25.99 Total Impact Points

Institutions

  • 2009–2011
    • Northeast Institute of Geography and Agroecology
      • • National Laboratory of Biomacromolecules
      • • Institute of Physics
      Peping, Beijing, China
  • 2007–2011
    • Chinese Academy of Sciences
      • Institute of Physics
      Peping, Beijing, China
  • 2010
    • Jiangnan University
      • School of Science
      Wu-hsi, Jiangsu Sheng, China
  • 2008–2010
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China