ICN2 Publications

2018

  • Optimisation of growth parameters to obtain epitaxial Y-doped BaZrO3 proton conducting thin films

    Magrasó A., Ballesteros B., Rodríguez-Lamas R., Sunding M.F., Santiso J. Solid State Ionics; 314: 9 - 16. 2018. 10.1016/j.ssi.2017.11.002.

    Nanomaterials Growth Division | Electron Microscopy Division

    We hereby report developments on the fabrication and characterization of epitaxial thin films of proton conducting Y-doped BaZrO3 (BZY) by pulsed laser deposition (PLD) on different single crystal substrates (MgO, GdScO3, SrTiO3, NdGaO3, LaAlO3 and sapphire) using Ni-free and 1% Ni-containing targets. Pure, high crystal quality epitaxial films of BZY are obtained on MgO and on perovskite-type substrates, despite the large lattice mismatch. The deposition conditions influence the morphology, cell parameters and chemical composition of the film, the oxygen partial pressure during film growth being the most determining. Film characterization was carried out using X-ray diffraction, transmission electron and atomic force microscopies, wavelength dispersive X-ray spectroscopy and angle-resolved X-ray photoelectron spectroscopy. All films show a slight tetragonal distortion that is not directly related to the substrate-induced strain. The proton conductivity of the films depends on deposition conditions and film thickness, and for the optimised conditions its total conductivity is slightly higher than the bulk conductivity of the target material (3 mS/cm at 600 °C, in wet 5% H2/Ar). The conductivities are, however, more than one order of magnitude lower than the highest reported in literature and possible reasoning is elucidated in terms of local and extended defects in the films. © 2017 Elsevier B.V.


  • Photoluminescent lateral flow based on non-radiative energy transfer for protein detection in human serum

    Zamora-Gálvez A., Morales-Narváez E., Romero J., Merkoçi A. Biosensors and Bioelectronics; 100: 208 - 213. 2018. 10.1016/j.bios.2017.09.013.

    Nanobioelectronics and Biosensors

    A new paper-based lateral flow immunoassay configuration was engineered and investigated. The assay is intended for the detection of a model protein in human serum, that is, human immunoglobulin G, with the aim to demonstrate a virtually universal protein detection platform. Once the sample is added in the strip, the analyte is selectively captured by antibody-decorated silica beads (Ab-SiO2) onto the conjugate pad and the sample flows by capillarity throughout the strip until reaching the test line, where a sandwich-like immunocomplex takes place due to the presence of antibody-functionalized QDs (Ab-QDs) onto the test line. Eventually, GO is added as a revealing agent and the photoluminescence of those sites protected by the complex Ab-SiO2/Antigen/Ab-QDs will not be quenched, whereas those photoluminescent sites directly exposed are expected to be quenched by GO, including the control line, made of bare QDs, reporting that the assay occurred successfully. Hence, the photoluminescence of the test line is modulated by the formation of sandwich-like immunocomplexes. The proposed device achieves a limit of detection (LOD) of 1.35 ng mL−1 in standard buffer, which is lower when compared with conventional lateral flow technology reported by gold nanoparticles, including other amplification strategies. Moreover, the resulting device was proven useful in human serum analysis, achieving a LOD of 6.30 ng mL−1 in this complex matrix. This low-cost disposable and easy-to-use device will prove valuable for portable and automated diagnostics applications, and can be easily transferred to other analytes such as clinically relevant protein biomarkers. © 2017


  • Ultrasensitive binder-free glucose sensors based on the pyrolysis of in situ grown Cu MOF

    Zhang X., Luo J., Tang P., Morante J.R., Arbiol J., Xu C., Li Q., Fransaer J. Sensors and Actuators, B: Chemical; 254: 272 - 281. 2018. 10.1016/j.snb.2017.07.024. IF: 5.401

    Advanced Electron Nanoscopy

    A non-enzymatic glucose sensor based on carbon/Cu composite materials was developed by the in-situ growth and subsequent pyrolysis of metal-organic frameworks (MOFs) on Cu foam. After pyrolysis, SEM, HRTEM and STEM-EELS were employed to clarify the hierarchical Cu@porous carbon electrode. It is found that the Cu nanoparticles are uniformly embedded in the carbon matrix, carbon matrix in close contact with the pyrolized carbon sheets. The electrocatalytic activity of the Cu@porous carbon matrix electrode for glucose sensing was explored by cyclic voltammetry (CV) and chronoamperometry. The resulting Cu@porous carbon matrix electrode displays ultrahigh sensitivity (10.1 mA cm−2 mM−1), low detection limit (0.6 μM), short response time (less than 2 s) and good stability, indicating that the developed electrode is a promising glucose sensor. © 2017 Elsevier B.V.