Chemical and biochemical sensors based on interferometry at thin (multi-) layers

Gauglitz, Güenter; Brecht, Andreas; Kraus, Gerolf; Mahm, W.

doi:10.1016/0925-4005(93)85234-2

Cited by 204 publications

(139 citation statements)

References 13 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…Spectral reflectance at near normal incidence is a wellestablished technique for in situ characterisation of thin metallic [68] or polymer [69] films. Here we expand this method by performing spectral reflectance measurements with a microscope: we thus obtain a diffraction-limited lateral resolution instead of an averaged measurement on a surface, opening the way to sub-micron mapping of thin layer heterogeneities.…”

Section: Spectral Reflectance Measurementsmentioning

confidence: 99%

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

2016

View full text Add to dashboard Cite

We describe a microscope-based optical setup that allows us to perform space-and time-resolved measurements of the spectral reflectance of transparent substrates coated with ultrathin films. This technique is applied to investigate the behavior in water of thermosensitive polymer brushes made of poly(N-isopropylacrylamide) grafted on glass. We show that spectral reflectance measurements yield quantitative information about the conformation and axial structure of the brushes as a function of temperature. We study how molecular parameters (grafting density, chain length) affect the hydration state of a brush, and provide one of the few experimental evidence for the occurrence of vertical phase separation in the vicinity of the lower critical solution temperature of the polymer. The origin of the hysteretic behavior of poly(N-isopropylacrylamide) brushes upon cycling the temperature is also clarified. We thus demonstrate that our optical technique allows for in-depth characterization of stimuli-responsive polymer layers, which is crucial for the rational design of smart polymer coatings in actuation, gating or sensing applications.

show abstract

Section: Spectral Reflectance Measurementsmentioning

confidence: 99%

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

2016

View full text Add to dashboard Cite

show abstract

“…Next, we used reflectometric interference spectroscopy to measure PtdIns3P binding quantitatively (33,34). In these experiments, silicon wafers with an oxide layer sufficiently thick for interference fringes were incubated with small unilamellar vesicles composed of 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) and 3% PtdIns3P.…”

Section: Requirement Of Both Binding Sites For Effective Phosphoinosimentioning

confidence: 99%

Structural and functional characterization of the two phosphoinositide binding sites of PROPPINs, a β-propeller protein family

Krick

Busse

Scacioc

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

160

234

View full text Add to dashboard Cite

β-propellers that bind polyphosphoinositides (PROPPINs), a eukaryotic WD-40 motif-containing protein family, bind via their predicted β-propeller fold the polyphosphoinositides PtdIns3P and PtdIns(3,5) P 2 using a conserved FRRG motif. PROPPINs play a key role in macroautophagy in addition to other functions. We present the 3.0-Å crystal structure of Kluyveromyces lactis Hsv2, which shares significant sequence homologies with its three Saccharomyces cerevisiae homologs Atg18, Atg21, and Hsv2. It adopts a seven-bladed β-propeller fold with a rare nonvelcro propeller closure. Remarkably, in the crystal structure, the two arginines of the FRRG motif are part of two distinct basic pockets formed by a set of highly conserved residues. In comprehensive in vivo and in vitro studies of ScAtg18 and ScHsv2, we define within the two pockets a set of conserved residues essential for normal membrane association, phosphoinositide binding, and biological activities. Our experiments show that PROPPINs contain two individual phosphoinositide binding sites. Based on docking studies, we propose a model for phosphoinositide binding of PROPPINs.autophagy | protein-lipid interactions | X-ray crystallography | yeast

show abstract

“…Spectral interferometry has been used as an feasible approach to detect changes in optical path length in thin films from immunoreactions [104]. Thin films were fixed to a glass substrate which located at the end of a bifurcated optical fiber.…”

Section: Sensing Schemesmentioning

confidence: 99%

Miniature fiber-optic multicavity Fabry–Perot interferometric biosensor

et al. 2005

View full text Add to dashboard Cite

(ABSTRACT)Fiber-optic Fabry-Perot interferometric (FFPI) sensors have been widely used due to their high sensitivity, ease of fabrication, miniature size, and capability for multiplexing. However, direct measurement of self-assembled thin films, receptor immobilization process or biological reaction is limited in the FFPI technique due to the difficulty of forming Fabry-Perot cavities by the thin film itself. Novel methods are needed to provide an accurate and reliable measurement for monitoring the thin-film growth in the nanometer range and under various conditions. In this work, two types of fiber-optic multicavity Fabry-Perot interferometric (MFPI) sensors with built-in temperature compensation were designed and fabricated for thin-film measurement, with applications in chemical and biological sensing. Both the tubing-based MFPI sensor and microgap MFPI sensor provide simple, yet high performance solutions for thin-film sensing. The temperature dependence of the sensing cavity is compensated by extracting the temperature information from a second multiplexed cavity. This provides the opportunity to examine the thin-film characteristics under different environment temperatures.To demonstrate the potential of this structure for practical applications, immunosensors were fabricated and tested using these structures. Self-assembled polyelectrolytes served as a precursor film for immobilization of antibodies to ensure they retain their biological activity. This not only provides a convenient method for protein immobilization but also presents the possibility of increasing the binding capacity

show abstract

Chemical and biochemical sensors based on interferometry at thin (multi-) layers

Cited by 204 publications

References 13 publications

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

Structural and functional characterization of the two phosphoinositide binding sites of PROPPINs, a β-propeller protein family

Miniature fiber-optic multicavity Fabry–Perot interferometric biosensor

Contact Info

Product

Resources

About