Person: Pérez García, Lucas
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First Name
Lucas
Last Name
Pérez García
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de Materiales
Area
Física Aplicada
Identifiers
5 results
Search Results
Now showing 1 - 5 of 5
Item Nanostructured gold electrodes promote neural maturation and network connectivity(Biomaterials, 2021) Dominguez-Bajo, Ana; Rosa, Juliana M.; González-Mayorga, Ankor; Rodilla González, Beatriz Loreto; Arché-Nuñez, Ana; Benayas, Esther; Ocón, Pilar; Pérez García, Lucas; Camarero, Julio; Miranda, Rodolfo; González, M. Teresa; Aguilar, Juan; Lopez-Dolado, Elisa; Serrano, María C.Progress in the clinical application of recording and stimulation devices for neural diseases is still limited, mainly because of suboptimal material engineering and unfavorable interactions with biological entities. Nanotechnology is providing upgraded designs of materials to better mimic the native extracellular environment and attain more intimate contacts with individual neurons, besides allowing for the miniaturization of the electrodes. However, little progress has been done to date on the understanding of the biological impact that such neural interfaces have on neural network maturation and functionality. In this work, we elucidate the effect of a gold (Au) highly ordered nanostructure on the morphological and functional interactions with neural cells and tissues. Alumina-templated Au nanostructured electrodes composed of parallel nanowires of 160 nm in diameter and 1.2 mu m in length (Au-NWs), with 320 nm of pitch, are designed and characterized. Equivalent non-structured Au electrodes (Au-Flat) are used for comparison. By using diverse techniques in in vitro cell cultures including live calcium imaging, we found that Au-NWs interfaced with primary neural cortical cells for up to 14 days allow neural networks growth and increase spontaneous activity and ability of neuronal synchronization, thus indicating that nanostructured features favor neuronal network. The enhancement in the number of glial cells found is hypothesized to be behind these beneficial functional effects. The in vivo effect of the implantation of these nanostructured electrodes and its potential relevance for future clinical applicability has been explored in an experimental model of rat spinal cord injury. Subacute responses to implanted Au-NWs show no overt reactive or toxic biological reactions besides those triggered by the injury itself. These results highlight the translational potential of Au-NWs electrodes for in vivo applications as neural interfaces in contact with central nervous tissues including the injured spinal cord.Item Flexible metallic core–shell nanostructured electrodes for neural interfacing(Scientific Reports, 2024) Rodilla González, Beatriz Loreto; Arché-Nuñez, Ana; Ruiz-Gómez, Sandra; Domínguez-Bajo, Ana; Fernández-González, Claudia; Guillén-Colomer, Clara; González-Mayorga, Ankor; Rodríguez-Díez, Noelia; Camarero, Julio; Miranda, Rodolfo; López-Dolado, Elisa; Ocón, Pilar; Serrano, María Concepción; Pérez García, Lucas; González, M. TeresaElectrodes with nanostructured surface have emerged as promising low-impedance neural interfaces that can avoid the charge‐injection restrictions typically associated to microelectrodes. In this work, we propose a novel approximation, based on a two-step template assisted electrodeposition technique, to obtain flexible nanostructured electrodes coated with core–shell Ni–Au vertical nanowires. These nanowires benefit from biocompatibility of the Au shell exposed to the environment and the mechanical properties of Ni that allow for nanowires longer and more homogeneous in length than their only-Au counterparts. The nanostructured electrodes show impedance values, measured by electrochemical impedance spectroscopy (EIS), at least 9 times lower than those of flat reference electrodes. This ratio is in good accordance with the increased effective surface area determined both from SEM images and cyclic voltammetry measurements, evidencing that only Au is exposed to the medium. The observed EIS profile evolution of Ni–Au electrodes over 7 days were very close to those of Au electrodes and differently from Ni ones. Finally, the morphology, viability and neuronal differentiation of rat embryonic cortical cells cultured on Ni–Au NW electrodes were found to besimilar to those on control (glass) substrates and Au NW electrodes, accompanied by a lower glial cell differentiation. This positive in-vitro neural cell behavior encourages further investigation to explore the tissue responses that the implantation of these nanostructured electrodes might elicit in healthy (damaged) neural tissues in vivo, with special emphasis on eventual tissue encapsulation.Item Direct x-ray detection of the spin hall effect in CuBi(Physical review X, 2022) Ruiz Gómez, Sandra; Guerrero, Rubén; Khaliq, Muhammad W; Fernández González, Claudia; Prat, Jordi; Valera, Andrés; Finizio, Simone; Perna, Paolo; Camarero, Julio; Pérez García, Lucas; Aballe, Lucía; Foerster, MichaelThe spin Hall effect and the inverse spin Hall effect are important spin-charge conversion mechanisms. The direct spin Hall effect induces a surface spin accumulation from a transverse charge current due to spin-orbit coupling even in nonmagnetic conductors. However, most detection schemes involve additional interfaces, leading to large scattering in reported data. Here we perform interface-free x-ray spectroscopy measurements at the Cu L_(3;2) absorption edges of highly Bi-doped Cu (Cu_(95)Bi_5). The detected x-ray magnetic circular dichroism signal corresponds to an induced magnetic moment of (2.2 + 0.5) x 10^(-12) mu(B) A^(-1) cm^(2) per Cu atom averaged over the probing depth, which is of the same order of magnitude as found for Pt measured by magneto-optics. The results highlight the importance of interface-free measurements to assess material parameters and the potential of CuBi for spin-charge conversion applications.Item Polystyrene nanopillars with inbuilt carbon nanotubes enable synaptic modulation and stimulation in interfaced neuronal networks(Advanced materials interfaces, 2021) Calaresu, Ivo; Hernández, Jaime; Rauti, Rossana; Rodilla, Beatriz L.; Arché-Núñez, Ana; Pérez García, Lucas; Camarero, Julio; Miranda, Rodolfo; González, M. Teresa; Rodríguez, Isabel; Scaini, Denis; Ballerini, LauraThe use of nanostructured materials and nanosized-topographies has the potential to impact the performance of implantable biodevices, including neural interfaces, enhancing their sensitivity and selectivity, while reducing tissue reactivity. As a result, current trends in biosensor technology require the effective ability to improve devices with controlled nanostructures. Nanoimprint lithography to pattern surfaces with high-density and high aspect ratio nanopillars (NPs) made of polystyrene (PS-NP, insulating), or of a polystyrene/carbon-nanotube nanocomposite (PS-CNT-NP, electrically conductive) are exploited. Both substrates are challenged with cultured primary neurons. They are demonstrated to support the development of suspended synaptic networks at the NPs' interfaces characterized by a reduction in proliferating neuroglia, and a boost in neuronal emergent electrical activity when compared to flat controls. The authors successfully exploit their conductive PS-CNT-NPs to stimulate cultured cells electrically. The ability of both nanostructured surfaces to interface tissue explants isolated from the mouse spinal cord is then tested. The integration of the neuronal circuits with the NP topology, the suspended nature of the cultured networks, the reduced neuroglia formation, and the higher network activity together with the ability to deliver electrical stimuli via PS-CNT-NP reveal such platforms as promising designs to implement on neuro-prosthetic or neurostimulation devices.Item Sub-nT resolution of single layer sensor based on the AMR effect in La_2/_3Sr_1/_3MnO_3 Thin Films(IEEE transactions on magnetics, 2022) Enger, Luiz Guilherme; Flament, Stephane; Bhatti, Imtiaz-Noor; Guillet, Bruno; Sing, Marc Lam Chok; Pierron, Victor; Lebargy, Sylvain; Díez, Jose Manuel; Vera, Arturo; Martínez, Isidoro; Guerrero, Rubén; Pérez García, Lucas; Perna, Paolo; Camarero, Julio; Miranda, Rodolfo; González, María Teresa; Mechin, LaurenceSingle-layer magnetoresistive sensors were designed in a Wheatstone bridge configuration using La_2/_3Sr_1/_3MnO_3 ferromagnetic oxide thin film. Uniaxial anisotropy was induced by performing epitaxial deposition of the films on top of vicinal SrTiO_3 substrate. X-ray scan confirms the high crystalline quality of the films and the magnetic anisotropy was checked by magneto-optical Kerr effect measurements. Thanks to the anisotropic magnetoresistive effect and the very low noise measured in the devices, sub-nT resolution was achieved above 100 Hz at 310 K.