1 research outputs found
High-Performance Implantable Sensors based on Anisotropic Magnetoresistive La<sub>0.67</sub>Sr<sub>0.33</sub>MnO<sub>3</sub> for Biomedical Applications
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