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Arrasate / Mondragón, Spain

Tavera T.,University of Navarra | Perez N.,University of Navarra | Rodriguez A.,CIC microGUNE | Yurrita P.,University of Navarra | And 2 more authors.
Applied Surface Science | Year: 2011

The production of periodic structures in silicon wafers by four-beam is presented. Because laser interference ablation is a single-step and cost-effective process, there is a great technological interest in the fabrication of these structures for their use as antireflection surfaces. Three different laser fluences are used to modify the silicon surface (0.8 J cm -2, 1.3 J cm-2, 2.0 J cm-2) creating bumps in the rim of the irradiated area. Laser induced periodic surface structures (LIPSS), in particular micro and nano-ripples, are also observed. Measurements of the reflectivity show a decrease in the reflectance for the samples processed with a laser fluence of 2.0 J cm-2, probably caused by the appearance of the nano-ripples in the structured area, while bumps start to deteriorate. © 2011 Elsevier B.V. All rights reserved. Source

Zuzuarregui A.,University of Navarra | Morant-Minana M.C.,CIC microGUNE | Perez-Lorenzo E.,University of Navarra | De Tejada G.M.,University of Navarra | And 2 more authors.
IEEE Sensors Journal | Year: 2014

In this paper, the implementation and characterization of a hand-held and simple biosensor for in-situ endotoxin determination are described. The integrated biosensor developed here is based on the electrochemical detection of endotoxin using polymyxin B as bioreceptor immobilized onto gold electrodes via a self-assembled monolayer. The cyclic voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy were used to characterize the biosensor performance and properties throughout the functionalization process. In addition, a comparative analysis of the behavior and features of two alternative electrochemical techniques for endotoxin detection was carried out. The biosensing device fabricated by thin-film technologies provided a simple and robust method to detect low concentrations of endotoxin. © 2001-2012 IEEE. Source

Harris L.F.,Dublin City University | Rainey P.,Queens University of Belfast | Castro-Lopez V.,CIC microGUNE | O'Donnell J.S.,St Jamess Hospital | And 2 more authors.
Analyst | Year: 2013

The development of new point of care coagulation assay devices is necessary due to the increasing number of patients requiring long-term anticoagulation in addition to the desire for appropriate, targeted anticoagulant therapy and a more rapid response to optimization of treatment. The majority of point of care devices currently available for hemostasis testing rely on clot-based endpoints which are variable, unreliable and limited to measuring only certain portions of the coagulation pathway. Here we present a novel fluorescence-based anti-Factor Xa (FXa) microfluidic assay device for monitoring the effect of anticoagulant therapy at the point of care. The device is a disposable, laminated polymer microfluidic strip fabricated from a combination of hydrophobic and hydrophilic cyclic polyolefins to allow reagent deposition in addition to effective capillary fill. Zeonor was the polymer of choice resulting in low background fluorescence (208.5 AU), suitable contact angles (17.5° ± 0.9°) and capillary fill times (20.3 ± 2.1 s). The device was capable of measuring unfractionated heparin and tinzaparin from 0-0.8 U ml-1 and enoxaparin from 0-0.6 U ml-1 with average CVs < 10%. A linear correlation was observed between the device and the fluorescent assay in the plate for plasma samples spiked with UFH, with an R2 value of 0.99, while correlations with tinzaparin and enoxaparin resulted in sigmoidal responses (R2 = 0.99). Plasma samples containing UFH resulted in a linear correlation between the device and a standard chromogenic assay with an R2 value of 0.98, with both LMWHs resulting in sigmoidal relationships (R2 = 0.99). This journal is © The Royal Society of Chemistry. Source

Harris L.F.,Dublin City University | Castro-Lopez V.,CIC microGUNE | Killard A.J.,Dublin City University | Killard A.J.,University of the West of England
TrAC - Trends in Analytical Chemistry | Year: 2013

Automated technologies have revolutionised the monitoring of coagulation disorders in the central hospital laboratory setting, allowing for high throughput testing, improved accuracy and precision, accompanied by a marked reduction in human error. However, they still require trained operators and sample transportation. With the advent of point of care (POC) testing, the working principle of traditional coagulometers was used as the foundation for the development of miniaturised devices. A number of POC coagulation devices have been commercially available for many years now, allowing the patient to assume more control over the management of their own medication, e.g. warfarin. While POC devices for measuring anticoagulation have relied principally on clotting time tests, novel platelet function tests, and factor-specific assays based on enzymatic or immunoassay principles are becoming available, driven by the emergence of new anticoagulant drugs, in addition to the inability of clotting tests to accurately detect many thrombotic disorders. This review highlights recent progress in the development of POC coagulation monitoring technologies and examines their future potential in clinical diagnostics. © 2013 Elsevier Ltd. Source

In this work we present a surface plasmon resonance sensor based on enhanced optical transmission through sub-wavelength nanohole arrays. This technique is extremely sensitive to changes in the refractive index of the surrounding medium which result in a modulation of the transmitted light. The periodic gold nanohole array sensors were fabricated by high-throughput thermal nanoimprint lithography. Square periodic arrays with sub-wavelength hole diameters were obtained and characterized. Using solutions with known refractive index, the array sensitivities were obtained. Finally, protein absorption was monitored in real-time demonstrating the label-free biosensing capabilities of the fabricated devices. Source

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