Surface plasmon resonance spectroscop

Balasubramanian S, Sorokulova IB, Vodyanoy VJ, Simonian AL (2007) Lytic phage as a specific and selective probe for detection of Staphylococcus aureus—a surface plasmon resonance spectroscopic study. Biosens Bioelectron 22 948-955... 

More recently, the method of scanning near-field optical microscopy (SNOM) has been applied to LB films of phospholipids and has revealed submicron-domain structures [55-59]. The method involves scanning a fiber-optic tip over a surface in much the same way an AFM tip is scanned over a surface. In principle, other optical experiments could be combined with the SNOM, snch as resonance energy transfer, time-resolved flnorescence, and surface plasmon resonance. It is likely that spectroscopic investigation of snbmicron domains in LB films nsing these principles will be pnrsned extensively. 

M. J. O Brien, V. H. Perez-Luna, S.R.J. Brueck, and G.P. Lopez, "A Surface plasmon Resonance Array Biosensor Based on Spectroscopic Imaging," Biosensors Bioelectronics 16, 97-108 (2001). 

Metal labels have been proposed to resolve problems connected with enzymes. Metal ions [13-16], metal-containing organic compounds [17,18], metal complexes [19-21], metalloproteins or colloidal metal particles [22-28] have served as labels. Spectrophotometric [22,25], acoustic [25], surface plasmon resonance, infrared [24] and Raman spectroscopic [28] methods, etc. were used. A few papers have been dealing with electrochemical detection. However, electrochemical methods of metal label detection may be viewed as very promising taking into account their high sensitivity, low detection limit, selectivity, simplicity, low cost and the availability of portable instruments. 

When optical anisotropies form spontaneously in the polymeric film during deposition, the situation is more complicated. Significant effects are observed in optical and spectroscopic properties, such as LED emission [17] and waveguide propagation [45-50,52,64], For these films, accurate evaluation of the optical constants is more difficult and must be based on variable incidence angle measurements, as in the case of surface plasmon resonance [45-47], waveguide propagation [48-50,52], ellipsometry [64,67], and reflectance/transmittance [68]. 

Fiber-optic biosensors are analytical devices in which a fiber optic device serves as a transduction element. The usual aim of fiber-optic biosensors is to produce a signal proportional to the concentration of target analyte to which the biological element reacts. Fiber-optic biosensors are based on the transmission of light along silica glass fiber, or POF to the site of analysis. They can be used in combination with different types of spectroscopic technique, e.g. absorption, fluorescence, phosphorescence, or surface plasmon resonance (SPR) (14). 

Raman spectroscopy can be used to detect normal modes of target molecules and also to monitor spectra of Raman labels that are used for one of the spectroscopic bar-codes. Raman bands in the vibrational Raman spectmm have intrinsically narrow bandwidths of ca. 10 cm, which, for example, correspond to less than 0.5 nm width in the visible region below 800 nm. The fluorescence of dye molecules has a broad bandwidth of 100 nm more or less. Hence, spectral overlap between fluorescence bands is inevitable and limits their use for multiplexed analysis. Quantum dots (QDs) have narrower bandwidth than dye-based fluorescence but stUl have broad bands that are several tens of nanometers. Light scattering of noble metal nanoparticles caused by surface plasmon resonance is also... 

Other spectroscopic techniques that have been used with electrochemistry to probe nanoparticles include electronic and vibrational spectroscopies. The spec-troelectrochemistry of nanosized silver particles based on their interaction with planar electrodes has been studied recently [146] using optically transparent thin layer electrodes (OTTLE). Colloidal silver shows a surface plasmon resonance absorption at 400 nm corresponding to 0.15 V vs. Ag/AgCl. This value blue shifts to 392 nm when an Au mesh electrode in the presence of Ag colloid is polarized to —0.6 V (figure 20.12). The absorption spectrum is reported to be quite reproducible and reversible. This indicates that the electron transfer occurs between the colloidal particles and a macroelectrode and vice versa. The kinetics of electron transfer is followed by monitoring the absorbance as a function of time. The use of an OTTLE cell ensures that the absorbance is due to all the particles in the cell between the cell walls and the electrode. The distance over which the silver particles will diffuse has been calculated to be 80 pm in 150 s, using a diffusion coef-... 

Single particle spectroscopic study on surface plasmon resonance of ion-adsorbed gold nanoparticles, in Nanoplasmonics From Fundamentals to Applications (eds S. Kawataand H. Masuhara), Elsevier, Amsterdam, pp. 219-228. 

Complementary spectroscopic studies have also helped to elaborate the factors controlling hybridization at DNA-modified surfaces." Surface plasmon resonance has been used to monitor DNA target capture in real time, and has confirmed that the efficiency of hybridization is maximized at surfaces sparsely covered with probe oligonucleotides. ... 

Most optical detection methods for biosensors are based on ultra-violet (UV) absorption spectrometry, emission spectroscopic measurement of fluorescence and luminescence, and Raman spectroscopy. However, surface plasmon resonance (SPR) has quickly been widely adopted as a nonlabeling technique that provides attractive advantages. Fueled by numerous new nanomateiials, their unique, SPR-based or related detection techniques are increasingly being investigated [28-31]. 

In this section we discuss methods in which (Ihoions provide both the primary beam and the detected beam. The techniques discussed arc listed in lable 21-1 namely, surface plasmon resonance,sum frequency generation, and e.lUpsometry. The electron and ion spectroscopic surface techniques described previously all suffer from one disadvantage they require an ultra-high vacuum environment and provide no access to buried interfaces. The photon spectroscopic melhods described here can all deal with surfaces in contact with liquids and, in some cases, surfaces that are buried under transparent layers. 

Spectroscopic ellipsometry, flow cell ATR-FTIR, flow cell Quartz crystal microbalance, flow cell Surface plasmon resonance, flow cell Surface force microscopy... 

X-ray photoelectron spectroscopy Surface plasmon resonance Quartz crystal microbalance Waveguide interfaometry (Spectroscopic) eUipsometry Fluorescence spectroscopy and microscopy (including immunofluorescence, total internal reflection fluorescence)... 

As a result of the heterogeneous distributions of electrical charge and chemical functionalities present on the surface of most proteins, the adsorption of proteins to solid substrates of differing surface properties may produce different molecular orientations. The optical thickness of protein layers can be evaluated by using el-lipsometry, surface plasmon resonance, or guided wave perturbation. When a chro-mophore of the protein is used as a probe, polarized spectroscopic techniques are found to be applicable to measure the tilt angle of the heme moiety in protein films. Macdonald and Smith used SERRS... 

Molecule 11 forms amphiphilic Pockels-Langmuir monolayers at the air-water interface, with a collapse pressure of 34 mN m and collapse areas of 50 A at 20 °C these monolayers transfer on the upstroke only, with transfer ratios around 100% onto hydrophilic glass, quartz, or aluminum,or onto fresh hydrophilic Au, but transfer poorly on the downstroke onto graphite, with a transfer ratio of only abont 50%. The LB monolayer thickness of 11 was 23-25 A by X-ray diffraction, spectroscopic ellip-sometry, surface plasmon resonance, and XPS. With... 

In the reflection mode, typically specular reflectance is measured on the electrode surface. It is anticipated that the variation of the surface structure (e.g., surface adsorption, phase transitions, etc.) will result in appreciable changes in the reflectivity properties. One can thus correlate the structural characterislics gleaned from spectroscopic measurements with electrochanical results. Figure 2.15 shows a cell assembly for internal reflection spectroelectrochemistry. Several spectroscopic techniques have been used, such as infrared, surface plasmon resonance, and X-ray based techniques (reflectivity, standing wave, etc.). Figure 2.16 depicts a cell setup for (A) infrared spectroelectrochemistry (IR-SEC) and (B) surface X-ray diffraction. 

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