Detection of biological signals from a live mammalian muscle using a diamond quantum sensor

TL;DR

This paper demonstrates a novel, noninvasive method to detect magnetic signals from live mammalian muscle tissue using diamond quantum sensors, offering a portable alternative to traditional cryogenic systems.

Contribution

It introduces a diamond-based quantum sensing technique capable of detecting magnetic fields from mammalian tissue without cryogenics, in unshielded environments.

Findings

Achieved 50pT/√Hz sensitivity in magnetic field detection.

First measurement of mammalian tissue signals with diamond sensors.

Operates effectively in unshielded lab environments.

Abstract

The ability to perform noninvasive, non-contact measurements of electric signals produced by action potentials is essential in biomedicine. A key method to do this is to remotely sense signals by the magnetic field they induce. Existing methods for magnetic field sensing of mammalian tissue, used in techniques such as magnetoencephalography of the brain, require cryogenically cooled superconducting detectors. These have many disadvantages in terms of high cost, flexibility and limited portability as well as poor spatial and temporal resolution. In this work we demonstrate an alternative technique for detecting magnetic fields generated by the current from action potentials in living tissue using nitrogen vacancy centres in diamond. With 50pT/$\sqrt{Hz}$ sensitivity, we show the first measurements of sensing from mammalian tissue with a diamond sensor using mouse muscle optogenetically activated with blue light. We show these measurements can be performed in an ordinary, unshielded lab environment and that the signal can be easily recovered by digital signal processing techniques.