Displaying publications 1 - 20 of 66 in total

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  1. 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
  2. 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*
  3. Daniyal WMEMM, Fen YW, Saleviter S, Chanlek N, Nakajima H, Abdullah J, et al.
    Polymers (Basel), 2021 Feb 02;13(3).
    PMID: 33540931 DOI: 10.3390/polym13030478
    In this study, X-ray photoelectron spectroscopy (XPS) was used to study chitosan-graphene oxide (chitosan-GO) incorporated with 4-(2-pyridylazo)resorcinol (PAR) and cadmium sulfide quantum dot (CdS QD) composite thin films for the potential optical sensing of cobalt ions (Co2+). From the XPS results, it was confirmed that carbon, oxygen, and nitrogen elements existed on the PAR-chitosan-GO thin film, while for CdS QD-chitosan-GO, the existence of carbon, oxygen, cadmium, nitrogen, and sulfur were confirmed. Further deconvolution of each element using the Gaussian-Lorentzian curve fitting program revealed the sub-peak component of each element and hence the corresponding functional group was identified. Next, investigation using surface plasmon resonance (SPR) optical sensor proved that both chitosan-GO-based thin films were able to detect Co2+ as low as 0.01 ppm for both composite thin films, while the PAR had the higher binding affinity. The interaction of the Co2+ with the thin films was characterized again using XPS to confirm the functional group involved during the reaction. The XPS results proved that primary amino in the PAR-chitosan-GO thin film contributed more important role for the reaction with Co2+, as in agreement with the SPR results.
    Matched MeSH terms: Surface Plasmon Resonance
  4. Zhang X, Wu X, Centeno A, Ryan MP, Alford NM, Riley DJ, et al.
    Sci Rep, 2016;6:23364.
    PMID: 26997140 DOI: 10.1038/srep23364
    Copper zinc tin sulfide (CZTS) is a promising material for harvesting solar energy due to its abundance and non-toxicity. However, its poor performance hinders their wide application. In this paper gold (Au) nanoparticles are successfully incorporated into CZTS to form Au@CZTS core-shell nanostructures. The photocathode of Au@CZTS nanostructures exhibits enhanced optical absorption characteristics and improved incident photon-to-current efficiency (IPCE) performance. It is demonstrated that using this photocathode there is a significant increase of the power conversion efficiency (PCE) of a photoelectrochemical solar cell of 100% compared to using a CZTS without Au core. More importantly, the PCE of Au@CZTS photocathode improved by 15.8% compared to standard platinum (Pt) counter electrode. The increased efficiency is attributed to plasmon resonance energy transfer (PRET) between the Au nanoparticle core and the CZTS shell at wavelengths shorter than the localized surface plasmon resonance (LSPR) peak of the Au and the semiconductor bandgap.
    Matched MeSH terms: Surface Plasmon Resonance
  5. 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
  6. 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*
  7. Junaid M, Khir MHM, Witjaksono G, Tansu N, Saheed MSM, Kumar P, et al.
    Molecules, 2020 Aug 11;25(16).
    PMID: 32796504 DOI: 10.3390/molecules25163646
    Graphene and its hybrids are being employed as potential materials in light-sensing devices due to their high optical and electronic properties. However, the absence of a bandgap in graphene limits the realization of devices with high performance. In this work, a boron-doped reduced graphene oxide (B-rGO) is proposed to overcome the above problems. Boron doping enhances the conductivity of graphene oxide and creates several defect sites during the reduction process, which can play a vital role in achieving high-sensing performance of light-sensing devices. Initially, the B-rGO is synthesized using a modified microwave-assisted hydrothermal method and later analyzed using standard FESEM, FTIR, XPS, Raman, and XRD techniques. The content of boron in doped rGO was found to be 6.51 at.%. The B-rGO showed a tunable optical bandgap from 2.91 to 3.05 eV in the visible spectrum with an electrical conductivity of 0.816 S/cm. The optical constants obtained from UV-Vis absorption spectra suggested an enhanced surface plasmon resonance (SPR) response for B-rGO in the theoretical study, which was further verified by experimental investigations. The B-rGO with tunable bandgap and enhanced SPR could open up the solution for future high-performance optoelectronic and sensing applications.
    Matched MeSH terms: Surface Plasmon Resonance/methods*
  8. Faried M, Suga K, Okamoto Y, Shameli K, Miyake M, Umakoshi H
    ACS Omega, 2019 Aug 27;4(9):13687-13695.
    PMID: 31497686 DOI: 10.1021/acsomega.9b01073
    A gold nanoparticle (AuNP) has a localized surface plasmon resonance peak depending on its size, which is often utilized for surface-enhanced Raman scattering (SERS). To obtain information on the cholesterol (Chol)-incorporated lipid membranes by SERS, AuNPs (5, 100 nm) were first functionalized by 1-octanethiol and then modified by lipids (AuNP@lipid). In membrane surface-enhanced Raman spectroscopy (MSERS), both signals from 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and Chol molecules were enhanced, depending on preparation conditions (size of AuNPs and lipid/AuNP ratio). The enhancement factors (EFs) were calculated to estimate the efficiency of AuNPs on Raman enhancement. The size of AuNP100nm@lipid was 152.0 ± 12.8 nm, which showed an surface enhancement Raman spectrum with an EF2850 value of 111 ± 9. The size of AuNP5nm@lipid prepared with a lipid/AuNP ratio of 1.38 × 104 (lipid molecule/particle) was 275.3 ± 20.2 nm, which showed the highest enhancement with an EF2850 value of 131 ± 21. On the basis of fluorescent probe analyses, the membrane fluidity and polarity of AuNP@lipid were almost similar to DOPC/Chol liposome, indicating an intact membrane of DOPC/Chol after modification with AuNPs. Finally, the membrane properties of AuNP@lipid systems were also discussed on the basis of the obtained MSERS signals.
    Matched MeSH terms: Surface Plasmon Resonance
  9. Masdor NA, Altintas Z, Shukor MY, Tothill IE
    Sci Rep, 2019 09 20;9(1):13642.
    PMID: 31541137 DOI: 10.1038/s41598-019-49672-2
    In this work, a subtractive inhibition assay (SIA) based on surface plasmon resonance (SPR) for the rapid detection of Campylobacter jejuni was developed. For this, rabbit polyclonal antibody with specificity to C. jejuni was first mixed with C. jejuni cells and unbound antibody was subsequently separated using a sequential process of centrifugation and then detected using an immobilized goat anti-rabbit IgG polyclonal antibody on the SPR sensor chip. This SIA-SPR method showed excellent sensitivity for C. jejuni with a limit of detection (LOD) of 131 ± 4 CFU mL-1 and a 95% confidence interval from 122 to 140 CFU mL-1. The method has also high specificity. The developed method showed low cross-reactivity to bacterial pathogens such as Salmonella enterica serovar Typhimurium (7.8%), Listeria monocytogenes (3.88%) and Escherichia coli (1.56%). The SIA-SPR method together with the culturing (plating) method was able to detect C. jejuni in the real chicken sample at less than 500 CFU mL-1, the minimum infectious dose for C. jejuni while a commercial ELISA kit was unable to detect the bacterium. Since the currently available detection tools rely on culturing methods, which take more than 48 hours to detect the bacterium, the developed method in this work has the potential to be a rapid and sensitive detection method for C. jejuni.
    Matched MeSH terms: Surface Plasmon Resonance
  10. Ashley J, Shukor Y, D'Aurelio R, Trinh L, Rodgers TL, Temblay J, et al.
    ACS Sens, 2018 02 23;3(2):418-424.
    PMID: 29333852 DOI: 10.1021/acssensors.7b00850
    Food recalls due to undeclared allergens or contamination are costly to the food manufacturing industry worldwide. As the industry strives for better manufacturing efficiencies over a diverse range of food products, there is a need for the development of new analytical techniques to improve monitoring of the presence of unintended food allergens during the food manufacturing process. In particular, the monitoring of wash samples from cleaning in place systems (CIP), used in the cleaning of food processing equipment, would allow for the effective removal of allergen containing ingredients in between food batches. Casein proteins constitute the biggest group of proteins in milk and hence are the most common milk protein allergen in food ingredients. As such, these proteins could present an ideal analyte for cleaning validation. In this work, molecularly imprinted polymer nanoparticles (nanoMIPs) with high affinity toward bovine α-casein were synthesized using a solid-phase imprinting method. The nanoMIPs were then characterized and incorporated into label free surface plasmon resonance (SPR) based sensor. The nanoMIPs demonstrated good binding affinity and selectivity toward α-casein (KD ∼ 10 × 10-9 M). This simple affinity sensor demonstrated the quantitative detection of α-casein achieving a detection limit of 127 ± 97.6 ng mL-1 (0.127 ppm) which is far superior to existing commercially available ELISA kits. Recoveries from spiked CIP wastewater samples were within the acceptable range (87-120%). The reported sensor could allow food manufacturers to adequately monitor and manage food allergen risk in food processing environments while ensuring that the food produced is safe for the consumer.
    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. Citartan M, Tang TH
    Talanta, 2019 Jul 01;199:556-566.
    PMID: 30952298 DOI: 10.1016/j.talanta.2019.02.066
    Aptamers are nucleic acid-based molecular recognition elements that are specific and have high binding affinity against their respective targets. On account of their target recognition capacity, aptamers are widely utilized in a number of applications including diagnostics. This review aims to highlight the recent developments of aptasensors expedient for point-of-care (POC) diagnostics. Significant focus is given on the primary assay formats of aptamers such as fluorescence, electrochemical, surface plasmon resonance (SPR) and colorimetric assays. A potpourri of platforms such as paper-based device, lateral flow assay, portable electrodes, portable SPR and smart phones expedient for point-of-care (POC) diagnostics are discussed. Emphasis is also given on the technicalities and assay configurations associated with the sensors.
    Matched MeSH terms: Surface Plasmon Resonance
  13. 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*
  14. Usman F, Dennis JO, Mkawi EM, Al-Hadeethi Y, Meriaudeau F, Ferrell TL, et al.
    Polymers (Basel), 2020 Nov 20;12(11).
    PMID: 33233844 DOI: 10.3390/polym12112750
    This work reports the use of a ternary composite that integrates p-Toluene sulfonic acid doped polyaniline (PANI), chitosan, and reduced graphene oxide (RGO) as the active sensing layer of a surface plasmon resonance (SPR) sensor. The SPR sensor is intended for application in the non-invasive monitoring and screening of diabetes through the detection of low concentrations of acetone vapour of less than or equal to 5 ppm, which falls within the range of breath acetone concentration in diabetic patients. The ternary composite film was spin-coated on a 50-nm-thick gold layer at 6000 rpm for 30 s. The structure, morphology and chemical composition of the ternary composite samples were characterized by FTIR, UV-VIS, FESEM, EDX, AFM, XPS, and TGA and the response to acetone vapour at different concentrations in the range of 0.5 ppm to 5 ppm was measured at room temperature using SPR technique. The ternary composite-based SPR sensor showed good sensitivity and linearity towards acetone vapour in the range considered. It was determined that the sensor could detect acetone vapour down to 0.88 ppb with a sensitivity of 0.69 degree/ppm with a linearity correlation coefficient of 0.997 in the average SPR angular shift as a function of the acetone vapour concentration in air. The selectivity, repeatability, reversibility, and stability of the sensor were also studied. The acetone response was 87%, 94%, and 99% higher compared to common interfering volatile organic compounds such as propanol, methanol, and ethanol, respectively. The attained lowest detection limit (LOD) of 0.88 ppb confirms the potential for the utilisation of the sensor in the non-invasive monitoring and screening of diabetes.
    Matched MeSH terms: Surface Plasmon Resonance
  15. Usman F, Dennis JO, Mkawi EM, Al-Hadeethi Y, Meriaudeau F, Fen YW, et al.
    Polymers (Basel), 2020 Nov 04;12(11).
    PMID: 33158093 DOI: 10.3390/polym12112586
    To non-invasively monitor and screen for diabetes in patients, there is need to detect low concentration of acetone vapor in the range from 1.8 ppm to 5 ppm, which is the concentration range of acetone vapor in diabetic patients. This work presents an investigation for the utilization of chitosan-polyethylene glycol (PEG)-based surface plasmon resonance (SPR) sensor in the detection of trace concentration acetone vapor in the range of breath acetone in diabetic subjects. The structure, morphology, and elemental composition of the chitosan-PEG sensing layer were characterized using FTIR, UV-VIS, FESEM, EDX, AFM, and XPS methods. Response testing was conducted using low concentration of acetone vapor in the range of 0.5 ppm to 5 ppm using SPR technique. All the measurements were conducted at room temperature and 50 mL/min gas flow rate. The sensor showed good sensitivity, linearity, repeatability, reversibility, stability, and high affinity toward acetone vapor. The sensor also showed better selectivity to acetone compared to methanol, ethanol, and propanol vapors. More importantly, the lowest detection limit (LOD) of about 0.96 ppb confirmed the applicability of the sensor for the non-invasive monitoring and screening of diabetes.
    Matched MeSH terms: Surface Plasmon Resonance
  16. 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
  17. Swamy MK, Akhtar MS, Mohanty SK, Sinniah UR
    PMID: 26186612 DOI: 10.1016/j.saa.2015.07.009
    Plant mediated synthesis of nanoparticles has been considered as green route and a reliable technique for the synthesis of nanoparticles due to its eco-friendly approach. In this study, we report a simple and eco-friendly approach for the synthesis of silver nanoparticles (AgNPs) using methanolic Momordica cymbalaria fruit extract as reducing agent. The fruit extract of M. cymbalaria exposed to AgNO3 solution showed the change in color from green to light yellow at room temperature within 1h of incubation confirms the synthesis of AgNPs. UV-vis spectra analysis revealed that the synthesized AgNPs had a sharp surface plasmon resonance at around 450 nm, while, the X-ray Diffraction (XRD) patterns confirmed distinctive peaks indices to the crystalline planes of the face centered cubic silver. The Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) analysis results confirmed the presence of spherical shaped AgNPs by a huge disparity in the particle size distribution with an average size of 15.5 nm. The synthesized AgNPs showed strong antibacterial activity against all the tested multidrug resistant human pathogenic bacterial strains and also exhibited highest free radical scavenging activity (74.2%) compared to fruit extract (60.4%). Moreover, both fruit extract and the synthesized AgNPs showed the cytotoxicity towards Rat L6 skeletal muscle cell line at different concentrations, but the highest inhibition percentage was recorded for AgNPs at concentration of 100 μg/ml.
    Matched MeSH terms: Surface Plasmon Resonance
  18. Anwar A, Ting ELS, Anwar A, Ain NU, Faizi S, Shah MR, et al.
    AMB Express, 2020 Feb 03;10(1):24.
    PMID: 32016777 DOI: 10.1186/s13568-020-0960-9
    Acanthamoeba spp. are the causative agent of Acanthamoeba keratitis and granulomatous amoebic encephalitis (GAE). The current options to treat Acanthamoeba infections have limited success. Silver nanoparticles show antimicrobial effects and enhance the efficacy of their payload at the specific biological targets. Natural folk plants have been widely used for treating diseases as the phytochemicals from several plants have been shown to exhibit amoebicidal effects. Herein, we used natural products of plant or commercial sources including quercetin (QT), kolavenic acid (PGEA) isolated from plant extracts of Polyalthia longifolia var pendula and crude plant methanolic extract of Caesalpinia pulcherrima (CPFLM) as antiacanthamoebic agents. Furthermore, these plant-based materials were conjugated with silver nanoparticles (AgNPs) to determine the effects of the natural compounds and their nanoconjugates against a clinical isolate of A. castellanii from a keratitis patient (ATCC 50492) belonging to the T4 genotype. The compounds were conjugated with AgNPs and characterized by using ultraviolet visible spectrophotometry and atomic force microscopy. Quercetin coated silver nanoparticles (QT-AgNPs) showed characteristic surface plasmon resonance band at 443 nm and the average size distribution was found to be around 45 nm. The natural compounds alone and their nanoconjugates were tested for the viability of amoebae, encystation and excystation activity against A. castellanii. The natural compounds showed significant growth inhibition of A. castellanii while QT-AgNPs specifically exhibited enhanced antiamoebic effects as well as interrupted the encystation and excystation activity of the amoebae. Interestingly, these compounds and nanoconjugates did not exhibit in vitro cytotoxic effects against human cells. Plant-based compounds and extracts could be an interesting strategy in development of alternative therapeutics against Acanthamoeba infections.
    Matched MeSH terms: Surface Plasmon Resonance
  19. 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*
  20. Hak CH, Sim LC, Leong KH, Lim PF, Chin YH, Saravanan P
    Environ Sci Pollut Res Int, 2018 Sep;25(25):25401-25412.
    PMID: 29951757 DOI: 10.1007/s11356-018-2632-8
    In this work, natural sunlight successfully induced the deposition of gold (Au), silver (Ag), and palladium (Pd) nanoparticles (NPs) with 17.10, 9.07, and 12.70 wt% onto the surface of graphitic carbon nitride (g-C3N4). The photocatalytic evaluation was carried out by adopting Bisphenol A (BPA) as a pollutant under natural sunlight irradiation. The presence of noble metals was confirmed by EDX, HRTEM, and XPS analysis. The deposition of Ag NPs (7.9 nm) resulted in the degradation rate which was 2.15-fold higher than pure g-C3N4 due to its relatively small particle size, contributing to superior charge separation efficiency. Au/g-C3N4 unveiled inferior photoactivity because the LSPR phenomenon provided two pathways for electron transfer between Au NPs and g-C3N4 further diminished the performance. The improved degradation lies crucially on the particle size and Schottky barrier formation at the interface of M/g-C3N4 (M=Au, Ag, and Pd) but not the visible light harvesting properties. The mechanism insight revealed the holes (h+) and superoxide radical (•O2-) radical actively involved in photocatalytic reaction for all composites.
    Matched MeSH terms: Surface Plasmon Resonance
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