High-Performance Implantable Sensors based on Anisotropic Magnetoresistive La_0.67Sr_0.33MnO₃ for Biomedical...

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Neural interfaces require sensitive, miniaturized magnetic-field sensors.
• Existing technologies face challenges with size, performance at body temperature, and biocompatibility.

Purpose of the Study:

• To design, fabricate, and characterize novel implantable neural interfaces.
• To utilize La_0.67Sr_0.33MnO₃ (LSMO) based anisotropic magnetoresistive (AMR) sensors for detecting neural magnetic signals.

Main Methods:

• Epitaxial growth engineering of LSMO for uniaxial anisotropy and high AMR output.
• Characterization of LSMO sensor performance (sensitivity, detectivity) at temperatures near 37 °C.
• In vitro and in vivo biocompatibility testing of submillimeter LSMO sensors coated with poly(dimethyl siloxane).

Main Results:

• Optimized LSMO sensors achieved high sensitivity (~400%/T) and low noise detectivity (2 nT·Hz^-1/2 at 1 Hz).
• Sensors demonstrated excellent performance at body temperature, suitable for low-frequency biological magnetic signal detection.
• Biocompatibility tests confirmed the suitability of the coated LSMO sensors for implantation.

Conclusions:

• The developed LSMO-based AMR sensors offer a promising solution for implantable neural interfaces.
• These sensors provide a combination of miniaturization, high performance at body temperature, and biocompatibility.
• The technology is well-suited for detecting subtle magnetic signals from neural activity in heterogeneous tissues.