Sensing magnetic flux density of artificial neurons with a MEMS device

Abstract

We describe a simple procedure to characterize a magnetic field sensor based on microelectromechanical systems (MEMS) technology, which exploits the Lorentz force principle. This sensor is designed to detect, in future applications, the spiking activity of neurons or muscle cells. This procedure is based on the well-known capability that a magnetic MEMS device can be used to sense a small magnetic flux density. In this work, an electronic neuron (FitzHugh-Nagumo) is used to generate controlled spike-like magnetic fields. We show that the magnetic flux density generated by the hardware of this neuron can be detected with a new MEMS magnetic field sensor. This microdevice has a compact resonant structure (700 × 600 × 5 μm) integrated by an array of silicon beams and p-type piezoresistive sensing elements, which need an easy fabrication process. The proposed microsensor has a resolution of 80 nT, a sensitivity of 1.2 V.T(-1), a resonant frequency of 13.87 kHz, low power consumption (2.05 mW), quality factor of 93 at atmospheric pressure, and requires a simple signal processing circuit. The importance of our study is twofold. First, because the artificial neuron can generate well-controlled magnetic flux density, we suggest it could be used to analyze the resolution and performance of different magnetic field sensors intended for neurobiological applications. Second, the introduced MEMS magnetic field sensor may be used as a prototype to develop new high-resolution biomedical microdevices to sense magnetic fields from cardiac tissue, nerves, spinal cord, or the brain.

Digital Signal Processing by Virtual Instrumentation of a MEMS Magnetic Field Sensor for Biomedical Applications

“…This sensor was designed and fabricated by the MEMS group from the Micro and Nanotechnology Research Center (MICRONA) of the Veracruzana University (Veracruz, Mexico) with collaboration of the Microelectronics Institute of Barcelona (IMB-CNM, CSIC, Bellatera, Spain) [38,40]. This sensor has a 700 × 600 × 5 μm resonant structure, formed by a rectangular loop, four bending silicon beams and an arrangement of transversal and longitudinal silicon beams.…”

Development of Resonant Magnetic Field Microsensors: Challenges and Future Applications

“…14). It was used for monitoring magnetic fields generate by an electronic neuron developed by researchers from Institute of Physiology-BUAP (Tapia et al, 2011). This microsensor exploits the Lorentz force and is formed by an arrangement of silicon microbeams (700  450  5 m) suspended by four bending microbeams, an aluminium loop (1 m thick), and a Wheatstone bridge with four p-type piezoresistors.…”

“…14. SEM image of a die with two resonant magnetic field microsensors with piezoresistive detection used for neural applications (Tapia et al, 2011).…”

Experimental analysis of out-of-plane Lorentz force actuated magnetic field sensor

“…Magnetoresistive sensors require deposition of magnetic materials and Hall-effect sensors show increase sensitivity at the cost of high power consumption [6]. Various designs of magnetic sensors are using a planar spiral coil, solenoid coil or toroid coil for coupling applications such as transformers and filters [7,8]. The coil based sensors affect volume density of the device.…”