Arrasate / Mondragón, Spain


Arrasate / Mondragón, Spain
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Eletxigerra U.,Micro NanoFabrication Unit | Martinez-Perdiguero J.,CIC microGUNE | Merino S.,Micro NanoFabrication Unit | Villalonga R.,Complutense University of Madrid | And 2 more authors.
Analytica Chimica Acta | Year: 2014

An amperometric immunoassay for the determination of tumor necrosis factor alpha (TNFα) protein biomarker in human serum based on the use of magnetic microbeads (MBs) and disposable screen-printed carbon electrodes (SPCEs) has been developed. The specifically modified microbeads were magnetically captured on the working electrode surface and the amperometric responses were measured at -0.20V (vs. Ag pseudo-reference electrode), upon addition of hydroquinone (HQ) as electron transfer mediator and H2O2 as the enzyme substrate. After a thorough optimization of the assay, extremely low limits of detection were achieved: 2.0pgmL-1 (36fM) and 5.8pgmL-1 (105fM) for standard solutions and spiked human serum, respectively. The simplicity, robustness and this clinically interesting LOD proved the developed TNFα immunoassay as a good contender for real clinical application. © 2014 Elsevier B.V.

Florea L.,Insight Centre for Data Analytics | Wagner K.,University of Wollongong | Wagner P.,University of Wollongong | Wallace G.G.,University of Wollongong | And 3 more authors.
Advanced Materials | Year: 2014

A study was conducted to demonstrate the first example of photo-driven chemopropulsion in which photo irradiation in close proximity to the micro-vehicle, a lipophilic droplet initiated a rapid pH change in the aqueous channel fluid in which the vehicle sat, as a result of the photo-induced dissociation of a water soluble organic acid. This led to a cascade of events involving protonation of the 2-hexyldecanoate ion in the fuel, rapid solubilization in the channel fluid of the released lipophilic CI-H+ , and an immediate change in surface tension of the fluid surrounding the droplet resulting in fast movement of the droplet away from the light source. The studied lipophilic droplet, typically contained a 1:1 (v:v) mixture of 2-hexyldecanoic acid (HDA) and 0.02 M chromoionophore I (CI) in dichloromethane (DCM), giving a large molar excess of HDA within the droplet.

Castro-Lopez V.,CIC microGUNE | Elizalde J.,CIC microGUNE | Elizalde J.,IKERLAN - IK4 | Pacek M.,POC Microsolutions | And 2 more authors.
Biosensors and Bioelectronics | Year: 2014

There is a general need in healthcare systems all around the world to reduce costs in terms of time and money without compromising patients outcome. Point-of-Care Testing (POCT) is currently being used in some applications (e.g. POC coagulation devices) as an alternative to already established standard central laboratory tests to overcome sample transportation and long turnaround times. The main objective of this investigation was to quantify Tumour Necrosis Factor-alpha (TNF-α) on-chip within the clinical relevant range of 5-100. pg/mL in human pooled plasma. The novel solid-phase assay developed in this study was a magnetic bead-based proximity ligation assay (PLA) in which one of the assay proximity probes was directly immobilised onto streptavidin-coated magnetic beads. The portable device was based on a disposable and single-use cyclo-olefin polymer (COP) microfluidic chip interfaced with a quantitative real-time polymerase chain reaction (qPCR) device previously developed in-house. Sample volume was 10. μL and total assay time under 3. h. The POC device and assay developed offer portability, smaller reagent and sample consumption, and faster time-to-results compared with standard ELISAs. Determination and monitoring of TNF-α therapy at the point-of-care will help to improve clinical and/or economical outcome in governmental healthcare budgets. © 2013 Elsevier B.V.

Harris L.F.,Dublin City University | Rainey P.,Queen's University of Belfast | Castro-Lopez V.,CIC MicroGUNE | O'Donnell J.S.,St James's 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.

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.

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.

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.

Morant-Minana M.C.,CIC microGUNE | Elizalde J.,CIC microGUNE | Elizalde J.,IKERLAN - IK4
Biosensors and Bioelectronics | Year: 2015

Campylobacter spp. are responsible for acute bacterial diseases in human worldwide. Nowadays campilobacteriosis is considered the most common foodborne illness in the European Union. In this paper the first electrochemical genosensor based on thin-film gold electrodes deposited onto Cyclo Olefin Polymer (COP) substrates was fabricated for the detection of Campylobacter spp in food matrices. The sensing element is characterized by several surface techniques and the sensitivity of the biosensor have been studied. A good linear relationship was obtained for the concentrations of PCR amplicon of Campylobacter spp. between 1 and 25. nM with a limit of detection (LOD) of 90. pM. Real samples have been validated with poultry meat samples and results were comparable with the PCR product samples. This is the last step for the fabrication of a Lab on a Chip (LOC), a biodevice integrating DNA sensor technology into microfluidic system, believed to perform an automated and complete assay, including sample preparation, PCR amplification, and electrochemical detection of Campylobacter spp. in raw poultry meat samples. © 2015 Elsevier B.V.

Benito-Lopez F.,CIC MicroGUNE | Benito-Lopez F.,Insight Centre for Data Analytics | Antonana-Diez M.,CIC MicroGUNE | Antonana-Diez M.,IKERLAN - IK4 | And 3 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2014

This paper reports for the first time the use of a cross-linked poly(N-isopropylacrylamide) ionogel encapsulating the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulphate as a thermoresponsive and modular microfluidic valve. The ionogel presents superior actuation behaviour to its equivalent hydrogel. Ionogel swelling and shrinking mechanisms and kinetics are investigated as well as the performance of the ionogel when integrated as a valve in a microfluidic device. The modular microfluidic valve demonstrates fully a reversible on-off behaviour without failure for up to eight actuation cycles and a pressure resistance of 1100 mbar. © 2014 the Partner Organisations.

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.

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