Displaying publications 1 - 20 of 66 in total

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  1. Opitz L, Zimmermann A, Lehmann S, Genzel Y, Lübben H, Reichl U, et al.
    J Virol Methods, 2008 Dec;154(1-2):61-8.
    PMID: 18840469 DOI: 10.1016/j.jviromet.2008.09.004
    Strategies to control influenza outbreaks are focused mainly on prophylactic vaccination. Human influenza vaccines are trivalent blends of different virus subtypes. Therefore and due to frequent antigenic drifts, strain independent manufacturing processes are required for vaccine production. This study verifies the strain independency of a capture method based on Euonymus europaeus lectin-affinity chromatography (EEL-AC) for downstream processing of influenza viruses under various culture conditions propagated in MDCK cells. A comprehensive lectin binding screening was conducted for two influenza virus types from the season 2007/2008 (A/Wisconsin/67/2005, B/Malaysia/2506/2004) including a comparison of virus-lectin interaction by surface plasmon resonance technology. EEL-AC resulted in a reproducible high product recovery rate and a high degree of contaminant removal in the case of both MDCK cell-derived influenza virus types demonstrating clearly the general applicability of EEL-AC. In addition, host cell dependency of EEL-AC was studied with two industrial relevant cell lines: Vero and MDCK cells. However, the choice of the host cell lines is known to lead to different product glycosylation profiles. Hence, altered lectin specificities have been observed between the two cell lines, requiring process adaptations between different influenza vaccine production systems.
    Matched MeSH terms: Surface Plasmon Resonance
  2. Ng SS, Lee SC, Bakhori SK, Hassan Z, Abu Hassan H, Yakovlev VA, et al.
    Opt Express, 2010 May 10;18(10):10354-9.
    PMID: 20588890 DOI: 10.1364/OE.18.010354
    Surface phonon polariton (SPP) characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure are investigated by means of p-polarized infrared (IR) attenuated total reflection spectroscopy. Two absorption dips corresponding to In(0.04)Al(0.06)Ga(0.90)N SPP modes are observed. In addition, two prominent dips and one relatively weak and broad dip corresponding to the Al(2)O(3) SPP mode, In(0.04)Al(0.06)Ga(0.90)N/Al(2)O(3) interface mode, and Al(2)O(3) bulk polariton mode, respectively, are clearly seen. No surface mode feature originating from the AlN layer is observed because it is too thin. Overall, the observations are in good agreement with the theoretical predictions.
    Matched MeSH terms: Surface Plasmon Resonance/methods*
  3. Yoke-Kqueen, C., Son, R.
    MyJurnal
    Application of surface plasmon resonance (SPR) biosensor in detection of genetically modified organism (GMO) is demonstrated. A total of four biotinylated probes namely Tnosb, P35Sb, LECb and TSQb were successfully immobilized onto the SA chip. Results analysis indicated that the SPR system with the sensor chip immobilized with the Tnosb, P35Sb, LECb and TSQb biotinylated probes potentially detect complementary standard fragments as low as 1 nM. Biospecific interaction analysis (BIA), employing surface plasmon resonance (SPR) and biosensor technologies provide easy, rapid and automatable approach in detection of GMOs. Short assay times, label free DNA hybridization reaction and no toxic compounds are required, i.e. ethidium bromide, and the reusability of the sensor surface are some of the factors that contribute to the general advantages of the surface plasmon resonance (SPR) biosensor system in detection of GMOs.
    Matched MeSH terms: Surface Plasmon Resonance
  4. Ali ME, Hashim U, Mustafa S, Man YB, Yusop MH, Bari MF, et al.
    Nanotechnology, 2011 May 13;22(19):195503.
    PMID: 21430321 DOI: 10.1088/0957-4484/22/19/195503
    We used 40 ± 5 nm gold nanoparticles (GNPs) as colorimetric sensor to visually detect swine-specific conserved sequence and nucleotide mismatch in PCR-amplified and non-amplified mitochondrial DNA mixtures to authenticate species. Colloidal GNPs changed color from pinkish-red to gray-purple in 2 mM PBS. Visually observed results were clearly reflected by the dramatic reduction of surface plasmon resonance peak at 530 nm and the appearance of new features in the 620-800 nm regions in their absorption spectra. The particles were stabilized against salt-induced aggregation upon the adsorption of single-stranded DNA. The PCR products, without any additional processing, were hybridized with a 17-base probe prior to exposure to GNPs. At a critical annealing temperature (55 °C) that differentiated matched and mismatched base pairing, the probe was hybridized to pig PCR product and dehybridized from the deer product. The dehybridized probe stuck to GNPs to prevent them from salt-induced aggregation and retained their characteristic red color. Hybridization of a 27-nucleotide probe to swine mitochondrial DNA identified them in pork-venison, pork-shad and venison-shad binary admixtures, eliminating the need of PCR amplification. Thus the assay was applied to authenticate species both in PCR-amplified and non-amplified heterogeneous biological samples. The results were determined visually and validated by absorption spectroscopy. The entire assay (hybridization plus visual detection) was performed in less than 10 min. The LOD (for genomic DNA) of the assay was 6 µg ml(-1) swine DNA in mixed meat samples. We believe the assay can be applied for species assignment in food analysis, mismatch detection in genetic screening and homology studies between closely related species.
    Matched MeSH terms: Surface Plasmon Resonance
  5. Levitskiy SA, Sycheva AM, Kharlampieva DD, Oberto J, Kamashev DE, Serebryakova MV, et al.
    Biochimie, 2011 Jul;93(7):1102-9.
    PMID: 21443922 DOI: 10.1016/j.biochi.2011.03.005
    HU is a most abundant DNA-binding protein in bacteria. This protein is conserved either in its heterodimeric form or in one of its homodimeric forms in all bacteria, in plant chloroplasts, and in some viruses. HU protein non-specifically binds and bends DNA as a hetero- or homodimer and can participate in DNA supercoiling and DNA condensation. It also takes part in some DNA functions such as replication, recombination, and repair. HU does not recognize any specific sequences but shows some specificity to cruciform DNA and to repair intermediates, e.g., nick, gap, bulge, 3'-overhang, etc. To understand the features of HU binding to DNA and repair intermediates, a fast and easy HU proteins purification procedure is required. Here we report overproduction and purification of the HU homodimers. The method of HU purification allows obtaining a pure recombinant non-tagged protein cloned in Escherichia coli. We applied this method for purification of Acholeplasma laidlawii HU and demonstrated that this protein possesses a DNA-binding activity and is free of contaminating nuclease activity. Besides that we have shown that expression of A. laidlawii ihf_hu gene in a slow-growing hupAB E. coli strain restores the wild-type growth indicating that aclHU can perform the basic functions of E. coli HU in vivo.
    Matched MeSH terms: Surface Plasmon Resonance
  6. Darroudi M, Ahmad MB, Zak AK, Zamiri R, Hakimi M
    Int J Mol Sci, 2011;12(9):6346-56.
    PMID: 22016663 DOI: 10.3390/ijms12096346
    Silver nanoparticles (Ag-NPs) were successfully synthesized using the UV irradiation of aqueous solutions containing AgNO(3) and gelatin as a silver source and stabilizer, respectively. The UV irradiation times influence the particles' diameter of the Ag-NPs, as evidenced from surface plasmon resonance (SPR) bands and transmission electron microscopy (TEM) images. When the UV irradiation time was increased, the mean size of particles continuously decreased as a result of photoinduced Ag-NPs fragmentation. Based on X-ray diffraction (XRD), the UV-irradiated Ag-NPs were a face-centered cubic (fcc) single crystal without any impurity. This study reveals that the UV irradiation-mediated method is a green chemistry and promising route for the synthesis of stable Ag-NPs for several applications (e.g., medical and surgical devices). The important advantages of this method are that it is cheap, easy, and free of toxic materials.
    Matched MeSH terms: Surface Plasmon Resonance
  7. Sadrolhosseini AR, Moksin MM, Nang HL, Norozi M, Yunus WM, Zakaria A
    Int J Mol Sci, 2011;12(4):2100-11.
    PMID: 21731429 DOI: 10.3390/ijms12042100
    In this study, optical and thermal properties of normal grade and winter grade palm oil biodiesel were investigated. Surface Plasmon Resonance and Photopyroelectric technique were used to evaluate the samples. The dispersion curve and thermal diffusivity were obtained. Consequently, the variation of refractive index, as a function of wavelength in normal grade biodiesel is faster than winter grade palm oil biodiesel, and the thermal diffusivity of winter grade biodiesel is higher than the thermal diffusivity of normal grade biodiesel. This is attributed to the higher palmitic acid C(16:0) content in normal grade than in winter grade palm oil biodiesel.
    Matched MeSH terms: Surface Plasmon Resonance
  8. Abdi MM, Abdullah LC, Sadrolhosseini AR, Mat Yunus WM, Moksin MM, Tahir PM
    PLoS One, 2011;6(9):e24578.
    PMID: 21931763 DOI: 10.1371/journal.pone.0024578
    A new sensing area for a sensor based on surface plasmon resonance (SPR) was fabricated to detect trace amounts of mercury and lead ions. The gold surface used for SPR measurements were modified with polypyrrole-chitosan (PPy-CHI) conducting polymer composite. The polymer layer was deposited on the gold surface by electrodeposition. This optical sensor was used for monitoring toxic metal ions with and without sensitivity enhancement by chitosan in water samples. The higher amounts of resonance angle unit (ΔRU) were obtained for PPy-CHI film due to a specific binding of chitosan with Pb(2+) and Hg(2+) ions. The Pb(2+) ion bind to the polymer films most strongly, and the sensor was more sensitive to Pb(2+) compared to Hg(2+). The concentrations of ions in the parts per million range produced the changes in the SPR angle minimum in the region of 0.03 to 0.07. Data analysis was done by Matlab software using Fresnel formula for multilayer system.
    Matched MeSH terms: Surface Plasmon Resonance/methods*
  9. Nengsih S, Umar AA, Salleh MM, Oyama M
    Sensors (Basel), 2012;12(8):10309-25.
    PMID: 23112601 DOI: 10.3390/s120810309
    The effect of morphology on the plasmonic sensing of the presence of formaldehyde in water by gold nanostructures has been investigated. The gold nanostructures with two different morphologies, namely spherical and rod, were prepared using a seed-mediated method. In typical results, it was found that the plasmonic properties of gold nanostructures were very sensitive to the presence of formaldehyde in their surrounding medium by showing the change in both the plasmonic peaks position and the intensity. Spherical nanoparticles (GNS), for example, indicated an increase in the sensitivity when the size was increased from 25 to 35 nm and dramatically decreased when the size was further increased. An m value, the ratio between plasmonic peak shift and refractive index change, as high as 36.5 nm/RIU (refractive index unit) was obtained so far. An expanded sensing mode to FD was obtained when gold nanostructures with nanorods morphology (GNR) were used because of the presence of two plasmonic modes for response probing. However, in the present study, effective plasmonic peak shift was not observed due to the intense plasmonic coupling of closely packed nanorod structures on the surface. Nevertheless, the present results at least provide a potential strategy for response enhancement via shape-effects. High performance plasmonic sensors could be obtained if controlled arrays of nanorods can be prepared on the surface.
    Matched MeSH terms: Surface Plasmon Resonance/instrumentation*; Surface Plasmon Resonance/methods
  10. Amin M, Anwar F, Janjua MRSA, Iqbal MA, Rashid U
    Int J Mol Sci, 2012;13(8):9923-9941.
    PMID: 22949839 DOI: 10.3390/ijms13089923
    A green synthesis route for the production of silver nanoparticles using methanol extract from Solanum xanthocarpum berry (SXE) is reported in the present investigation. Silver nanoparticles (AgNps), having a surface plasmon resonance (SPR) band centered at 406 nm, were synthesized by reacting SXE (as capping as well as reducing agent) with AgNO(3) during a 25 min process at 45 °C. The synthesized AgNps were characterized using UV-Visible spectrophotometry, powdered X-ray diffraction, and transmission electron microscopy (TEM). The results showed that the time of reaction, temperature and volume ratio of SXE to AgNO(3) could accelerate the reduction rate of Ag(+) and affect the AgNps size and shape. The nanoparticles were found to be about 10 nm in size, mono-dispersed in nature, and spherical in shape. In vitro anti-Helicobacter pylori activity of synthesized AgNps was tested against 34 clinical isolates and two reference strains of Helicobacter pylori by the agar dilution method and compared with AgNO(3) and four standard drugs, namely amoxicillin (AMX), clarithromycin (CLA), metronidazole (MNZ) and tetracycline (TET), being used in anti-H. pylori therapy. Typical AgNps sample (S1) effectively inhibited the growth of H. pylori, indicating a stronger anti-H. pylori activity than that of AgNO(3) or MNZ, being almost equally potent to TET and less potent than AMX and CLA. AgNps under study were found to be equally efficient against the antibiotic-resistant and antibiotic-susceptible strains of H. pylori. Besides, in the H. pylori urease inhibitory assay, S1 also exhibited a significant inhibition. Lineweaver-Burk plots revealed that the mechanism of inhibition was noncompetitive.
    Matched MeSH terms: Surface Plasmon Resonance
  11. Citartan M, Gopinath SC, Tominaga J, Tang TH
    Analyst, 2013 Jul 7;138(13):3576-92.
    PMID: 23646346 DOI: 10.1039/c3an36828a
    Reporting biomolecular interactions has become part and parcel of many applications of science towards an in-depth understanding of disease and gene regulation. Apart from that, in diagnostic applications where biomolecules (antibodies and aptamers) are vastly applied, meticulous monitoring of biomolecular interaction is vital for clear-cut diagnosis. Several currently available methods of analyzing the interaction of the ligands with the appropriate analytes are aided by labeling using fluorescence or luminescence techniques. However, labeling is cumbersome and can occupy important binding sites of interactive molecules to be labeled, which may interfere with the conformational changes of the molecules and increase non-specificity. Optical-based sensing can provide an alternative way as a label-free procedure for monitoring biomolecular interactions. Optical sensors affiliated with different operating principles, including surface plasmon changes, scattering and interferometry, can impart a huge impact for in-house and point-of-care applications. This optical-based biosensing permits real-time monitoring, obviating the use of hazardous labeling molecules such as radioactive tags. Herein, label-free ways of reporting biomolecular interactions by various optical biosensors were gleaned.
    Matched MeSH terms: Surface Plasmon Resonance
  12. Soon CF, Khaghani SA, Youseffi M, Nayan N, Saim H, Britland S, et al.
    Colloids Surf B Biointerfaces, 2013 Oct 1;110:156-62.
    PMID: 23711786 DOI: 10.1016/j.colsurfb.2013.04.012
    Widefield surface plasmon resonance (WSPR) microscopy provides high resolution imaging of interfacial interactions. We report the application of the WSPR imaging system in the study of the interaction between keratinocytes and liquid crystals (LC). Imaging of fixed keratinocytes cultured on gold coated surface plasmon substrates functionalized with a thin film of liquid crystals was performed in air using a 1.45NA objective based system. Focal adhesion of the cells adhered to glass and LC were further studied using immunofluorescence staining of the vinculin. The imaging system was also simulated with 2×2 scattering matrix to investigate the optical reflection of the resonant plasmonic wave via the glass/gold/cell and glass/gold/LC/cell layers. WSPR imaging indicated that keratinocytes are less spread and formed distinct topography of cell-liquid crystal couplings when cultured on liquid crystal coated substrates. The simulation indicates that glass/LC shifted the surface plasmon excitation angle to 75.39° as compared to glass/air interface at 44°. The WSPR microcopy reveals that the cells remodelled their topography of adhesion at different interfaces.
    Matched MeSH terms: Surface Plasmon Resonance*
  13. Jahanshahi P, Zalnezhad E, Sekaran SD, Adikan FR
    Sci Rep, 2014 Jan 24;4:3851.
    PMID: 24458089 DOI: 10.1038/srep03851
    Surface plasmon resonance (SPR) is a medical diagnosis technique with high sensitivity and specificity. In this research, a new method based on SPR is proposed for rapid, 10-minute detection of the anti-dengue virus in human serum samples. This novel technique, known as rapid immunoglobulin M (IgM)-based dengue diagnostic test, can be utilized quickly and easily at the point of care. Four dengue virus serotypes were used as ligands on a biochip. According to the results, a serum volume of only 1 μl from a dengue patient (as a minimized volume) is required to indicate SPR angle variation to determine the ratio of each dengue serotype in samples with 83-93% sensitivity and 100% specificity.
    Matched MeSH terms: Surface Plasmon Resonance
  14. Kashif M, Bakar AA, Arsad N, Shaari S
    Sensors (Basel), 2014 Aug 28;14(9):15914-38.
    PMID: 25171117 DOI: 10.3390/s140915914
    Surface plasmon resonance (SPR) is a novel optical sensing technique with a unique ability to monitor molecular binding in real-time for biological and chemical sensor applications. Interferometry is an excellent tool for accurate measurement of SPR changes, the measurement and comparison is made for the sensitivity, dynamic range and resolution of the different analytes using interferometry techniques. SPR interferometry can also employ phase detection in addition to the amplitude of the reflected light wave, and the phase changes more rapidly compared with other approaches, i.e., intensity, angle and wavelength. Therefore, the SPR phase interferometer offers the advantages of spatial phase resolution and high sensitivity. This work discusses the advancements in interferometric SPR methods to measure the phase shifts due to refractive index changes. The main application areas of SPR sensors are demonstrated, i.e., the Fabry-Perot interferometer, Michelson interferometer and Mach-Zehnder interferometer, with different configurations. The three interferometers are discussed in detail, and solutions are suggested to enhance the performance parameters that will aid in future biological and chemical sensors.
    Matched MeSH terms: Surface Plasmon Resonance/instrumentation*
  15. Chong SS, Aziz AR, Harun SW, Arof H
    Sensors (Basel), 2014;14(9):15836-48.
    PMID: 25166498 DOI: 10.3390/s140915836
    In this study, the construction and test of tapered plastic optical fiber (POF) sensors, based on an intensity modulation approach are described. Tapered fiber sensors with different diameters of 0.65 mm, 0.45 mm, and 0.35 mm, were used to measure various concentrations of Remazol black B (RBB) dye aqueous solutions at room temperature. The concentrations of the RBB solutions were varied from 0 ppm to 70 ppm. In addition, the effect of varying the temperature of the RBB solution was also investigated. In this case, the output of the sensor was measured at four different temperatures of 27 °C, 30 °C, 35 °C, and 40 °C, while its concentration was fixed at 50 ppm and 100 ppm. The experimental results show that the tapered POF with d = 0.45 mm achieves the best performance with a reasonably good sensitivity of 61 × 10(-4) and a linearity of more than 99%. It also maintains a sufficient and stable signal when heat was applied to the solution with a linearity of more than 97%. Since the transmitted intensity is dependent on both the concentration and temperature of the analyte, multiple linear regression analysis was performed to combine the two independent variables into a single equation. The resulting equation was then validated experimentally and the best agreement between the calculated and experimental results was achieved by the sensor with d = 0.45 mm, where the minimum discrepancy is less than 5%. The authors conclude that POF-based sensors are suitable for RBB dye concentration sensing and, with refinement in fabrication, better results could be achieved. Their low fabrication cost, simple configuration, accuracy, and high sensitivity would attract many potential applications in chemical and biological sensing.
    Matched MeSH terms: Surface Plasmon Resonance/instrumentation*
  16. Mohd Sultan N, Johan MR
    ScientificWorldJournal, 2014;2014:184604.
    PMID: 25215315 DOI: 10.1155/2014/184604
    Gold nanoparticles (AuNPs) had been synthesized with various molarities and weights of reducing agent, monosodium glutamate (MSG), and stabilizer chitosan, respectively. The significance of chitosan as stabilizer was distinguished through transmission electron microscopy (TEM) images and UV-Vis absorption spectra in which the interparticles distance increases whilst retaining the surface plasmon resonance (SPR) characteristics peak. The most stable AuNPs occurred for composition with the lowest (1 g) weight of chitosan. AuNPs capped with chitosan size stayed small after 1 month aging compared to bare AuNPs. The ability of chitosan capped AuNPs to uptake analyte was studied by employing amorphous carbon nanotubes (α-CNT), copper oxide (Cu2O), and zinc sulphate (ZnSO4) as the target material. The absorption spectra showed dramatic intensity increased and red shifted once the analyte was added to the chitosan capped AuNPs.
    Matched MeSH terms: Surface Plasmon Resonance
  17. Jahanshahi P, Ghomeishi M, Adikan FR
    ScientificWorldJournal, 2014;2014:503749.
    PMID: 24616635 DOI: 10.1155/2014/503749
    The most common permittivity function models are compared and identifying the best model for further studies is desired. For this study, simulations using several different models and an analytical analysis on a practical surface Plasmon structure were done with an accuracy of ∼ 94.4% with respect to experimental data. Finite element method, combined with dielectric properties extracted from the Brendel-Bormann function model, was utilized, the latter being chosen from a comparative study on four available models.
    Matched MeSH terms: Surface Plasmon Resonance/methods*
  18. Sadrolhosseini AR, Noor AS, Bahrami A, Lim HN, Talib ZA, Mahdi MA
    PLoS One, 2014;9(4):e93962.
    PMID: 24733263 DOI: 10.1371/journal.pone.0093962
    Polypyrrole multi-walled carbon nanotube composite layers were used to modify the gold layer to measure heavy metal ions using the surface plasmon resonance technique. The new sensor was fabricated to detect trace amounts of mercury (Hg), lead (Pb), and iron (Fe) ions. In the present research, the sensitivity of a polypyrrole multi-walled carbon nanotube composite layer and a polypyrrole layer were compared. The application of polypyrrole multi-walled carbon nanotubes enhanced the sensitivity and accuracy of the sensor for detecting ions in an aqueous solution due to the binding of mercury, lead, and iron ions to the sensing layer. The Hg ion bonded to the sensing layer more strongly than did the Pb and Fe ions. The limitation of the sensor was calculated to be about 0.1 ppm, which produced an angle shift in the region of 0.3° to 0.6°.
    Matched MeSH terms: Surface Plasmon Resonance/methods*
  19. Singho ND, Johan MR, Lah NA
    Nanoscale Res Lett, 2014;9(1):42.
    PMID: 24450850 DOI: 10.1186/1556-276X-9-42
    Ag/PMMA nanocomposites were successfully synthesized by in-situ technique. Transmission electron microscopy (TEM) images show that the particles are spherical in shape and their sizes are dependent on temperature. The smallest particle achieved high stability as indicated from Zeta sizer analysis. The red shift of surface plasmon resonance (SPR) indicated the increases of particle sizes. X-ray diffraction (XRD) patterns exhibit a two-phase (crystalline and amorphous) structure of Ag/PMMA nanocomposites. The complexation of Ag/PMMA nanocomposites was confirmed using Raman spectroscopy. Fourier transform infrared spectroscopy spectra confirmed that the bonding was dominantly influenced by the PMMA and DMF solution. Finally, thermogravimetric analysis (TGA) results indicate that the total weight loss increases as the temperature increases.
    Matched MeSH terms: Surface Plasmon Resonance
  20. Fen YW, Yunus WM, Talib ZA, Yusof NA
    PMID: 25004894 DOI: 10.1016/j.saa.2014.06.081
    In this study, novel active nanolayers in combination with surface plasmon resonance (SPR) system for zinc ion (Zn(2+)) detection has been developed. The gold surface used for the SPR system was modified with the novel developed active nanolayers, i.e. chitosan and chitosan-tetrabutyl thiuram disulfide (chitosan-TBTDS). Both chitosan and chitosan-TBTDS active layers were fabricated on the gold surface by spin coating technique. The system was used to monitor SPR signal for Zn(2+) in aqueous media with and without sensitivity enhancement by TBTDS. For both active nanolayers, the shift of resonance angle is directly proportional to the concentration of Zn(2+) in aqueous media. The higher shift of resonance angle was obtained for chitosan-TBTDS active nanolayer due to a specific binding of TBTDS with Zn(2+). The chitosan-TBTDS active nanolayer enhanced the sensitivity of detection down to 0.1 mg/l and also induced a selective detection towards Zn(2+).
    Matched MeSH terms: Surface Plasmon Resonance/instrumentation*; Surface Plasmon Resonance/methods*
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