2023 - 31/01/2023 ACS Biomater. Sci. Eng.
High-Performance Implantable Sensors based on Anisotropic Magnetoresistive La0.67Sr0.33MnO3 for Biomedical Applications
Arturo Vera, Isidoro Martínez, Luiz Guilherme Enger, Bruno Guillet, Rubén Guerrero, José Manuel Diez, Olivier Rousseau, Marc Lam Chok Sing, Victor Pierron, Paolo Perna, Jaime J. Hernández, Isabel Rodríguez, Ivo Calaresu, Anja Meier, Carmen Huck, Ana Domínguez-Bajo, Ankor González-Mayorga, Elisa López-Dolado, María C. Serrano, Laura Ballerini, Lucas Pérez, Rodolfo Miranda, Stéphane Flament, María Teresa González*, Laurence Méchin, and Julio Camarero
Abstract:
We present the design, fabrication, and characterization of an implantable neural interface based on anisotropic magnetoresistive (AMR) magnetic-field sensors that combine reduced size and high performance at body temperature. The sensors are based on La0.67Sr0.33MnO3 (LSMO) as a ferromagnetic material, whose epitaxial growth has been suitably engineered to get uniaxial anisotropy and large AMR output together with low noise even at low frequencies. The performance of LSMO sensors of different film thickness and at different temperatures close to 37 °C has to be explored to find an optimum sensitivity of ∼400%/T (with typical detectivity values of 2 nT·Hz–1/2 at a frequency of 1 Hz and 0.3 nT·Hz–1/2 at 1 kHz), fitted for the detection of low magnetic signals coming from neural activity. Biocompatibility tests of devices consisting of submillimeter-size LSMO sensors coated by a thin poly(dimethyl siloxane) polymeric layer, both in vitro and in vivo, support their high suitability as implantable detectors of low-frequency biological magnetic signals emerging from heterogeneous electrically active tissues.