Institute of Photonics and Electronics

Prague, Czech Republic

Institute of Photonics and Electronics

Prague, Czech Republic
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Pimkova K.,Institute of Hematology and Blood Transfusion | Bockova M.,Institute of Photonics and Electronics | Hegnerova K.,Institute of Photonics and Electronics | Suttnar J.,Institute of Hematology and Blood Transfusion | And 3 more authors.
Analytical and Bioanalytical Chemistry | Year: 2012

The surface plasmon resonance (SPR) biosensor system with dispersionless microfluidics for the direct and label-free detection of a soluble vascular endothelial growth factor receptor (sVEGFR-1) is described. The detection approach takes advantage of an affinity interaction between sVEGFR-1 and its ligand, vascular endothelial growth factor (VEGF-A), which is covalently immobilized on the surface of the SPR sensor. The ability of the immobilized VEGF-A to specifically bind the sVEGFR-1 receptor is demonstrated in a buffer. The detection of sVEGFR-1 in 2% human blood plasma is carried out by using the sequential injection approach. The detection limit of 25 ng/mL is achieved. In addition, we demonstrate that the functional surface of the sensor can be regenerated for repeated use. [Figure not available: see fulltext.] © 2011 Springer-Verlag.

Yatskiv R.,Institute of Photonics and Electronics | Verde M.,Institute of Photonics and Electronics | Grym J.,Institute of Photonics and Electronics
Key Engineering Materials | Year: 2015

Arrays of vertically well aligned ZnO nanorods (NRs) were prepared on nanostructured ZnO films using a low temperature hydrothermal method. We propose the use of the low cost, environmentally friendly electrophoretic deposition technique (EPD) as seeding procedure, which allows the obtaining of homogeneous, well oriented nanostructured ZnO thin films. ZnO nanorod arrays were covered with graphite in order to prepare graphite/ZnO NRs junctions. These nanostructured junctions showed promising current-voltage rectifying characteristics and gas sensing properties at room temperature. © (2015) Trans Tech Publications, Switzerland.

Lynn N.S.,Institute of Photonics and Electronics | Martinez-Lopez J.-I.,Monterrey Institute of Technology | Bockova M.,Institute of Photonics and Electronics | Adam P.,Institute of Photonics and Electronics | And 3 more authors.
Biosensors and Bioelectronics | Year: 2014

The combination of microarray technologies with microfluidic sample delivery and real-time detection methods has the capability to simultaneously monitor 10-1000. s of biomolecular interactions in a single experiment. Despite the benefits that microfluidic systems provide, they typically operate in the laminar flow regime under mass transfer limitations, where large analyte depletion layers act as a resistance to analyte capture. By locally stirring the fluid and delivering fresh analyte to the capture spot, the use of passive mixing structures in a microarray environment can reduce the negative effects of these depletion layers and enhance the sensor performance. Despite their large potential, little attention has been given to the integration of these mixing structures in microarray sensing environments. In this study, we use passive mixing structures to enhance the mass transfer of analyte to a capture spot within a microfluidic flow cell. Using numerical methods, different structure shapes and heights were evaluated as means to increase local fluid velocities, and in turn, rates of mass transfer to a capture spot. These results were verified experimentally via the real-time detection of 20-mer ssDNA for an array of microspots. Both numerical and experimental results showed that a passive mixing structure situated directly over the capture spot can significantly enhance the binding rate of analyte to the sensing surface. Moreover, we show that these structures can be used to enhance mass transfer in experiments regarding an array of capture spots. The results of this study can be applied to any experimental system using microfluidic sample delivery methods for microarray detection techniques. © 2013 Elsevier B.V.

Yatskiv R.,Institute of Photonics and Electronics | Zdansky K.,Institute of Photonics and Electronics | Grym J.,Institute of Photonics and Electronics
Key Engineering Materials | Year: 2013

We investigated Schottky diode hydrogen sensors prepared by printing colloidal graphite on ZnO, GaN, and InP substrates partly covered with Pt nanoparticles. A layer of Pt nanoparticles deposited by in-situ pulsed electrophoretic deposition from isooctane colloidal solutions was inserted between the semimetal graphite and the semiconductor surface to dissociate hydrogen molecules. Schottky diodes were investigated by the measurement of current-voltage characteristics and further tested for their sensitivity to hydrogen in a cell with a through-flow gas system. The sensing elements were sensitive to gas mixture with a low hydrogen concentration down to 1 ppm. © (2013) Trans Tech Publications.

Harun S.W.,University of Malaya | Paul M.C.,Indian Central Glass and Ceramic Research Institute | Moghaddam M.R.A.,University of Malaya | Das S.,Indian Central Glass and Ceramic Research Institute | And 5 more authors.
Laser Physics | Year: 2010

Highly efficient laser action from an Ytterbium-doped fiber (YDF) is demonstrated using a fiber Bragg grating (FBG) in conjunction with a 4% Fresnel reflection at room temperature. The YDF used is drawn from Yb2O 3-doped preform, fabricated through deposition of porous layer of composition SiO2-GeO2 by the MCVD process in conjunction with a solution doping technique. The fabricated YDF has a core composition of 0.2 wt % of Yb2O3, 1.8 wt % of Al2O3 and 23 wt % of GeO2 with a pump absorption of 9.0 dB/m. The fiber laser operates at wavelength of 1028 nm with a slope efficiency of 88% with respect to the launched 976 nm pump power using the YDF length of 7 m. © 2010 Pleiades Publishing, Ltd.

Yatskiv R.,Institute of Photonics and Electronics | Grym J.,Institute of Photonics and Electronics
NANOCON 2015 - 7th International Conference on Nanomaterials - Research and Application, Conference Proceedings | Year: 2015

We report photoluminescence properties of hydrothermally grown ZnO nanorods (NRs) before and after hydrogen peroxide (H2O2) treatment. The H2O2 treatment introduces oxygen related defects and thus enhances chemisorption processes in ZnO NRs. These effects amplify interactions between the gas species and adsorbed oxygen and thus can influence sensing properties of ZnO NRs.

Giorgini A.,National Research Council Italy | Avino S.,National Research Council Italy | Malara P.,National Research Council Italy | Gagliardi G.,National Research Council Italy | And 7 more authors.
Optics Letters | Year: 2013

We report on a method for surface plasmon resonance (SPR) refractive index sensing based on direct time-domain measurements. An optical resonator is built around an SPR sensor, and its photon lifetime is measured as a function of loss induced by refractive index variations. The method does not rely on any spectroscopic analysis or direct intensity measurement. Time-domain measurements are practically immune to light intensity fluctuations and thus lead to high resolution. A proof of concept experiment is carried out in which a sensor response to liquid samples of different refractive indices is measured. A refractive index resolution of the current system, extrapolated from the reproducibility of cavity-decay time determinations over 133 s, is found to be about 10-5RIU. The possibility of longterm averaging suggests that measurements with a resolution better than 10-7 RIU/√p Hz are within reach. © 2013 Optical Society of America.

Komanec M.,Czech Technical University | Honzatko P.,Institute of Photonics and Electronics | Zvanovec S.,Czech Technical University
Microwave and Optical Technology Letters | Year: 2010

An all-optical single-shot sampling oscilloscope with a picosecond resolution is developed. An innovative approach for data pulse replication using a polarization-maintaining resonator is used. Pulses are sampled in a highly nonlinear fiber. Acquired data are used for pulse shape reconstruction. Proposed setup eliminates the need of a delay line. © 2010 Wiley Periodicals, Inc.

Zdansky K.,Institute of Photonics and Electronics | Dickerson J.H.,Vanderbilt University
Sensors and Actuators, B: Chemical | Year: 2013

The electrophoretic deposition (EPD) of nanoparticles (NPs) of the catalytic metal platinum (Pt) onto semiconductor wafers of indium phosphide (InP) from colloid solution in isooctane was studied at room temperature. The colloid solution for EPD was prepared by the chemical reduction of water solutions of the metal salts, confined to AOT reverse micelles in isooctane with hydrazine reducing agent. Four EPD-cast samples of Pt NPs were prepared on polished n-type InP wafers with varying times of deposition. The sheet density of Pt NPs varied from approximately 10% coverage of the substrate to 100% coverage of the substrate by several monolayers of Pt NPs, as observed by SEM. EPD was performed on a masked surface, enabling to make separated small deposited spots. Schottky contacts were made on the deposited spots by printing the contacts with colloidal graphite. The time response of the current to a 0.1% hydrogen exposure exhibited a continuous increase of saturation current and a decrease of the response time with increasing Pt NPs sheet density. Layers of Pt NPs were also prepared on p-type InP wafers. The current of the p-type InP diodes was observed to decrease with the exposure to hydrogen; its decrease was much smaller than the increase of current in n-type InP diodes. This demonstrates that two mechanisms are involved in formation of the hydrogen dipole layer. We have suggested the increase in hydrogen affinity by correlation effects as the second mechanism added to the well known hydrogen polarization by the electric field of the Schottky barrier. © 2013 Elsevier B.V.

Zdansky K.,Institute of Photonics and Electronics | Yatskiv R.,Institute of Photonics and Electronics
Sensors and Actuators, B: Chemical | Year: 2012

The paper reports on InP and GaN Schottky diode hydrogen sensors prepared by printing colloidal graphite on InP and GaN with catalytic metal Pd, Pt or bimetal Pd/Pt nanoparticles (NPs), electrophoretic depositions of metal NPs on surfaces of semiconductor wafers were performed from isooctane colloid solutions prepared by reverse micelles technique with dioctyl sodium sulfosuccinate (AOT) surfactant. Deposited metal NPs were characterized by SEM. Current voltage characteristics of the diodes showed high rectification ratio (about 10 7 at voltage 1 V), low leakage currents and high Schottky barrier heights giving evidence of small Fermi level pinning. Currents changed by more than six orders of magnitude after diode exposures to 0.1% hydrogen in nitrogen, showing extremely high sensitivity of hydrogen detection. Time response of the current of forward voltage biased diodes to exposure of various concentrations of hydrogen in nitrogen was measured in the range from 1 to 1000 ppm of hydrogen. The detection limit of hydrogen was estimated at 0.5 ppm. © 2012 Elsevier B.V. All rights reserved.

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