Sensitivity of grating couplers as integrated-optical chemical sensors

Tiefenthaler, K.; Lukosz, W.

doi:10.1364/josab.6.000209

Cited by 614 publications

(434 citation statements)

References 11 publications

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“…Denoting the phase shifts upon reflexion by 0, this gives us the condition: Substituting the 0 derived previously from $ (equations 53-55, 60) leads to the 4-layer mode equations. For d A <^ k (as will generally be the case in protein deposition experiments), the equations may be linearized (Tiefenthaler & Lukosz, 1989) to give:…”

Section: Integrated Optics (10)mentioning

confidence: 99%

Experimental methods for investigating protein adsorption kinetics at surfaces

Ramsden¹

1994

Quart. Rev. Biophys.

177

131

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The adsorption of proteins at the solid-liquid interface is a process of fundamental importance in nature. Extensive reviews (MacRitchie, 1978; Andrade & Hlady, 1986; Norde, 1986) testify to the strong interest which has been shown in the problem during the past few decades. Norde & Lyklema (1978) have rightly pointed out that protein adsorption is scientifically intriguing; the phenomenology is complicated and includes many presently apparently irreconcilable observations.

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Section: Integrated Optics (10)mentioning

confidence: 99%

Experimental methods for investigating protein adsorption kinetics at surfaces

Ramsden¹

1994

Quart. Rev. Biophys.

177

131

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“…This angle scan is automatically performed by the IOS, yielding the incoupling angles (at maximal intensity of guided light reaching the detectors) for the two polarizations of the light, transverse electric, TE, and transverse magnetic, TM. These angles aTE and aT;u are directly related to the effective waveguide indices N T E and N T M , i.e., the ratio of the vacuum velocity of light to its velocity along the waveguide, by the incoupling condition (Tiefenthaler & Lukosz, 1989). It is written here for the first grating order and in the positive direction:…”

Section: Waveguide Theory and Data Processingmentioning

confidence: 99%

“…This is expressed in the mode equation (Tiefenthaler & Lukosz, 1989;Spohn, 1994): where kz,F is the perpendicular wave vector component of the wave guided in the film F, dF the thickness of the film (the product k,,FdF is the phase shift upon traversing the waveguide), and +F,s and 4F,c are the phase shifts upon total internal reflection at the interfaces, waveguiding film Fhubstrate S , and film F/cover medium C, respectively. These phase shifts are different for the two polarizations of the light.…”

Section: Waveguide Theory and Data Processingmentioning

confidence: 99%

“…This evanescent wave traveling along the waveguide surface is modified by the presence of an organic layer on top of the waveguide. This adlayer changes the values of kz,F and the phase shifts 4F,A,c, and thus tunes the resonance to new effective indices N. An extensive treatment of this "four-layer planar waveguide model" is given elsewhere (Tiefenthaler & Lukosz, 1989). It consists of the glass support (index S), the waveguiding film (F), the organic adlayer (A), and the cover medium (C), with the corresponding parameters: thickness d, refractive index n, effective waveguide index N. We calculated thickness values dA for the organic adlayer from the effective waveguide indices NTE and NTM provided by the 10s with the following formulae, derived from the mode equation and the The coefficient p is set to zero for the TE-mode, to 1 for the TM-mode.…”

Section: Waveguide Theory and Data Processingmentioning

confidence: 99%

“…For these calculations, the refractive indices of buffer nc, waveguiding film nF, and glass support ns, as well as the waveguide thickness dF, have to be known. cal tool by Tiefenthaler and Lukosz (1989). Covalent linkage between the lipid bilayer and the solid support offers mechanically stable, long-lasting, and regenerable membranes that may also have important practical applications for the development of a new class of biosensors using membrane protein receptors as the biologically selective recognition element.…”

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confidence: 99%

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Covalent attachment of functionalized lipid bilayers to planar waveguides for measuring protein binding to biomimetic membranes

et al. 1995

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A new method is presented for measuring sensitively the interactions between ligands and their membrane-bound receptors in situ using integrated optics, thus avoiding the need for additional labels. Phospholipid bilayers were attached covalently to waveguides by a novel protocol, which can in principle be used with any glass-like surface.In a first step, phospholipids carrying head-group thiols were covalently immobilized onto Si02-Ti02 waveguide surfaces. This was accomplished by acylation of aminated waveguides with the heterobifunctional crosslinker N-succinimidyl-3-maleimidopropionate, followed by the formation of thioethers between the surface-grafted maleimides and the synthetic thiolipids. The surface-attached thiolipids served as hydrophobic templates and anchors for the deposition of a complete lipid bilayer either by fusion of lipid vesicles or by lipid self-assembly from mixed lipid/detergent micelles. The step-by-step lipid bilayer formation on the waveguide surface was monitored in situ by an integrated optics technique, allowing the simultaneous determination of optical thickness and one of the two refractive indices of the adsorbed organic layers. Surface coverages of 50-60% were calculated for thiolipid layers. Subsequent deposition of POPC resulted in an overall lipid layer thickness of 45-50 A , which corresponds to the thickness of a fluid bilayer membrane.Specific recognition reactions occurring at cell membrane surfaces were modeled by the incorporation of lipidanchored receptor molecules into the supported bilayer membranes. (1) The outer POPC layer was doped with biotinylated phosphatidylethanolamine. Subsequent specific binding of streptavidin was optically monitored. (2) A lipopeptide was incorporated in the outer POPC monolayer. Membrane binding of monoclonal antibodies, which were directed against the peptide moiety of the lipopeptide, was optically detected. The specific antibody binding correlated well with the lipopeptide concentration in the outer monolayer.

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Optical biosensors

Ramsden¹

1997

J. Mol. Recognit.

118

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Sensitivity of grating couplers as integrated-optical chemical sensors

Cited by 614 publications

References 11 publications

Experimental methods for investigating protein adsorption kinetics at surfaces

Experimental methods for investigating protein adsorption kinetics at surfaces

Covalent attachment of functionalized lipid bilayers to planar waveguides for measuring protein binding to biomimetic membranes

Optical biosensors

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