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Martinez-Perdiguero J.,CIC microGUNE | Martinez-Perdiguero J.,Micro NanoFabrication Unit | Mendizabal L.,Micro NanoFabrication Unit | Morant-Minana M.C.,CIC microGUNE | And 9 more authors.
Thin Solid Films | Year: 2015

The electrical properties of dielectric thin layers deposited on conducting substrates still need to be thoroughly characterized for a wide variety of applications such as solar modules, flexible displays and sensor integration. In this work, thin dielectric films composed of layers and alternated multilayers of SiO2 and Al2O3 up to a total thickness of 3 μm have been deposited on flexible rough stainless steel substrates by means of reactive magnetron sputtering. Their electrical properties have been studied focusing on important parameters such as leakage current density and disruptive field strengths. Moreover, temperature annealing and bending effects have been quantified. It is concluded that the best electrical properties with this type of materials are achieved with multilayered structures. © 2015 Elsevier B.V.


Eletxigerra U.,Micro NanoFabrication Unit | Martinez-Perdiguero J.,CIC microGUNE | Merino S.,Micro NanoFabrication Unit | Barderas R.,Complutense University of Madrid | And 4 more authors.
Biosensors and Bioelectronics | Year: 2015

A highly sensitive amperometric magnetoimmunosensor for the determination of ErbB2 protein, a well-known biomarker related to high-impact high-incidence diseases such as breast cancer, is described. A sandwich format involving the covalent immobilization of a specific capture antibody onto magnetic beads (MBs) and incubation of the modified MBs with a mixture solution of the antigen and a HRP-labeled detector antibody was used. The resulting modified MBs were captured on the surface of a disposable screen-printed carbon electrode (SPCE) and the amperometric responses at -0.20V were measured. This ErbB2 magnetoimmunosensor exhibited a very low detection limit of 26pgmL- 1 far below the established cut-off for this biomarker (15ngmL-1) and was successfully applied to the quantitation of ErbB2 in human serum and cell lysates samples without any matrix effect. In addition, the developed assay allowed the assessment of ErbB2 status directly in intact breast cancer cells. The results correlated well with those obtained with a commercial ELISA method, thus demonstrating that the new magnetoimmunosensing platform offers a truthful and useful analytical tool to be easily applied in breast cancer diagnosis through either ErbB2 protein determination or breast cancer cell status detection. © 2015 Elsevier B.V.


Eletxigerra U.,Micro NanoFabrication Unit | Martinez-Perdiguero J.,Micro NanoFabrication Unit | Merino S.,Micro NanoFabrication Unit | Barderas R.,Complutense University of Madrid | And 4 more authors.
Electroanalysis | Year: 2016

An electrochemical magnetoimmunosensor for the determination of progesterone receptor (PR) making use of functionalized magnetic microbeads (MBs), a sandwich-type immunoassay and amperometric detection at disposable screen-printed carbon electrodes (SPCEs) was described for the first time in this work. This selective and sensitive magnetoimmunosensor, with a detection limit of 22 pg mL−1, was successfully applied to the determination of PR in raw cell lysates with just a dilution as sample treatment and exhibiting no matrix effect. The advantageous performance in terms of simplicity and assay time over commercial ELISAs makes it competitive with conventional strategies providing rapidly quantitative and reliable results on this biomarker currently used in the clinical practice for diagnosis, follow-up and monitoring of metastatic breast cancer. In addition, a dual magnetoimmunosensor using screen-printed dual carbon electrode (SPdCE) has been implemented for the simultaneous determination of PR and estrogen receptor α (ERα) in cell lysates. This dual receptor determination allows a more accurate diagnosis enabling a more efficient treatment. The usefulness of this dual magnetoimmunosensing platform was demonstrated by discriminating raw lysates of two types of cancer cells (MCF-7 and MDA-MB-436) with significantly different PR/ERα expression levels. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Eletxigerra U.,Micro NanoFabrication Unit | Martinez-Perdiguero J.,Micro NanoFabrication Unit | Martinez-Perdiguero J.,University of the Basque Country | Barderas R.,Complutense University of Madrid | And 3 more authors.
Analytica Chimica Acta | Year: 2016

A highly sensitive surface plasmon resonance (SPR) immunosensor for the important ErbB2 breast cancer biomarker has been developed. Optimization of the assay has been carried out, including signal enhancement employing gold nanoparticles (GNPs). The effect of the signal amplification of the GNPs has been also studied. The assay has been tested with clinically relevant matrices. Results in 50% human serum yielded a LOD of 180 pg mL-1 which is a concentration 83 times lower than the clinical cut-off. Raw lysates from model breast cancer cell lines (SK-BR-3, MCF-7 and MDA-MB-436) have been also assayed and higher quantities of the ErbB2 protein were clearly observed in the ErbB2 over-expressing case (SK-BR-3). The results confirmed that the simple and highly sensitive SPR immunosensor represents a feasible tool for ErbB2 detection. © 2015 Elsevier B.V.


Martinez-Perdiguero J.,micro Microtechnologies Cooperative Research Center | Retolaza A.,micro Microtechnologies Cooperative Research Center | Retolaza A.,Micro NanoFabrication Unit | Bujanda L.,University of the Basque Country | And 2 more authors.
Talanta | Year: 2014

A simple method for the detection of TNF-alpha protein biomarker in human serum with great sensitivity has been developed using a surface plasmon resonance biosensor. Signal amplification based on a sandwich immunoassay including gold nanoparticles was used. Detection in serum proved to be challenging due to high undesirable non-specific binding to the sensor surface stemming from the matrix nature of the sample. After optimization of the assay parameters and, in the case of serum, of a sample dilution buffer to minimize the non-specific binding, very low limits of detection were achieved: 11.6 pg/mL (211 fM) and 54.4 pg/mL (989 fM) for spiked buffer and human serum respectively. The amplification steps with high affinity biotinylated antibodies and streptavidin-fuctionalized nanoparticles greatly enhanced the signal with the advantage of additional specificity. Due to its simplicity and sensitivity, the immunoassay has proved feasible to be used for detection of low concentration biomarkers in real samples. © 2013 Elsevier B.V.


Eletxigerra U.,Micro NanoFabrication Unit | Martinez-Perdiguero J.,Micro NanoFabrication Unit | Merino S.,Micro NanoFabrication Unit
Sensors and Actuators, B: Chemical | Year: 2015

This paper presents a disposable microfluidic electrochemical immunosensor for rapid, cheap and quantitative detection of biomarkers. Dual screen-printed carbon electrodes were biofunctionalized with specific antibodies and subsequently encapsulated with an all-disposable polymeric microfluidic cell. The electrochemical detection was carried out by means of differential pulse voltammetry (DPV) using a portable potentiostat. One of the two working electrodes was employed as an on-chip integrated negative control. The system was optimized and characterized for the detection of tumor necrosis factor alpha (TNFα), an important inflammation biomarker, with a limit of detection (LOD) of 4.1 ng/mL. Successful experiments in real human serum were also carried out. © 2015 Elsevier B.V. All rights reserved.


Eletxigerra U.,Micro NanoFabrication Unit | Martinez-Perdiguero J.,Micro NanoFabrication Unit | Merino S.,Micro NanoFabrication Unit | Barderas R.,Complutense University of Madrid | And 4 more authors.
Sensing and Bio-Sensing Research | Year: 2016

An electrochemical magnetoimmunosensor for the determination of estrogen receptor α (ERα) protein in complex samples (serum and cell lysates) able to discriminate between ERα positive and negative breast cancer cells is reported. Specifically functionalized magnetic microbeads with sandwich immunocomplexes and amperometric detection at disposable screen-printed carbon electrodes (SPCEs) resulted in highly selective and sensitive ERα detection with a detection limit of 19 pg mL-1. This magnetoimmunosensing platform was successfully applied to the quantitation of ERα in spiked human serum and cell lysates samples without any matrix effect with an advantageous performance in terms of simplicity and assay times over commercial ELISA assays. The biosensor capability for assessing ERα in intact breast cancer cells makes it competitive with conventional strategies providing rapidly quantitative and reliable results on this relevant biomarker currently used in the clinical practice for diagnosis, follow-up and monitoring of metastatic breast cancer. © 2016 The Authors.


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.


PubMed | Micro NanoFabrication Unit, CIC microGUNE and Complutense University of Madrid
Type: | Journal: Biosensors & bioelectronics | Year: 2015

A highly sensitive amperometric magnetoimmunosensor for the determination of ErbB2 protein, a well-known biomarker related to high-impact high-incidence diseases such as breast cancer, is described. A sandwich format involving the covalent immobilization of a specific capture antibody onto magnetic beads (MBs) and incubation of the modified MBs with a mixture solution of the antigen and a HRP-labeled detector antibody was used. The resulting modified MBs were captured on the surface of a disposable screen-printed carbon electrode (SPCE) and the amperometric responses at -0.20 V were measured. This ErbB2 magnetoimmunosensor exhibited a very low detection limit of 26 pg mL(-1) far below the established cut-off for this biomarker (15 ng mL(-1)) and was successfully applied to the quantitation of ErbB2 in human serum and cell lysates samples without any matrix effect. In addition, the developed assay allowed the assessment of ErbB2 status directly in intact breast cancer cells. The results correlated well with those obtained with a commercial ELISA method, thus demonstrating that the new magnetoimmunosensing platform offers a truthful and useful analytical tool to be easily applied in breast cancer diagnosis through either ErbB2 protein determination or breast cancer cell status detection.

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