Non-invasive magnetocardiography of living rat based on diamond quantum sensor

TL;DR

This paper introduces a novel, room-temperature, diamond-based magnetocardiography system capable of non-invasively detecting weak cardiac magnetic signals in living rats, advancing quantum sensing for medical diagnostics.

Contribution

The study demonstrates a high-sensitivity, compact, solid-state MCG system using NV centers in diamond, enabling non-invasive cardiac monitoring in small animals at room temperature.

Findings

Achieved 9 pT/Hz^{1/2} sensitivity in magnetic detection.

Successfully captured rat cardiac signals with ~20 pT amplitude.

Extended quantum sensing from microscopic to macroscopic biological applications.

Abstract

Magnetocardiography (MCG) has emerged as a sensitive and precise method to diagnose cardiovascular diseases, providing more diagnostic information than traditional technology. However, the sensor limitations of conventional MCG systems, such as large size and cryogenic requirement, have hindered the widespread application and in-depth understanding of this technology. In this study, we present a high-sensitivity, room-temperature MCG system based on the negatively charged Nitrogen-Vacancy (NV) centers in diamond. The magnetic cardiac signal of a living rat, characterized by an approximately 20 pT amplitude in the R-wave, is successfully captured through non-invasive measurement using this innovative solid-state spin sensor. To detect these extremely weak biomagnetic signals, we utilize sensitivity-enhancing techniques such as magnetic flux concentration. These approaches have enabled us to simultaneously achieve a magnetometry sensitivity of 9 $\text{pT}\cdot \text{Hz}^{-1/2}$ and a sensor scale of 5 $\text{mm}$. By extending the sensing scale of the NV centers from cellular and molecular level to macroscopic level of living creatures, we have opened the future of solid-state quantum sensing technologies in clinical environments.