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Spindiag Acquisition Frontend

Spindiag Acquisition Frontend

  • Project title: Spindiag
  • CEA collaborators: SPEC LNO
  • Project status: 6 months starting 09-2019; first prototype assembled 02-2020; tested, then another prototype in 2023; currently in service in the DIAMSS project
  • Keywords: GMR sensor, Wheatstone bridge, ×8600 amplification, low noise, battery

The LNO Nanomagnetism and Oxide laboratory developed GMR sensors to detect weak magnetic fields. In a global health application, LNO proposes detecting specific bacteria that have been tagged with specific antibodies and labeled with magnetic microbeads. These pass through a microfluidic channel to be detected by two GMR sensors facing each other. The electrical signals from these two sensors require appropriate analog processing (Wheatstone bridge, high-pass filter, amplification, low-pass filter). A metal enclosure and a two-channel electronic board with high gain (×8300), low noise, and battery power were designed and validated by a student.

Illustration of the principle of labeled bacteria flowing through a microfluidic channel above a GMR sensor.
Photograph of the microfluidic channel integrated into the sensor chip mounted on a PCB for signal acquisition.
Electronic signal-amplification board, first prototype, battery-powered to ensure a high signal-to-noise ratio.