Detection of biological signals from gastrocnemius muscle in living animals with SERF atomic magnetometer

Magnetomyography (MMG) provides a non-invasive approach to detect the magnetic fields generated by muscle. Compared with the traditional electromyography (EMG), it offers advantages such as without tissue interference and non-invasive operation. However, MMG signals are extremely weak and easily disturbed by environmental noise, posing significant challenges, especially in small animal models. To address this problem, we developed a high-sensitivity MMG detection system based on a spin-exchange relaxation-free (SERF) optically pumped magnetometer (OPM) for living animals. A single-beam rubidium SERF OPM was integrated in this system, achieving a sensitivity of 20 fT/Hz1/2. Subsequently, MMG signals from the gastrocnemius muscle of a guinea pig were successfully recorded using this system. This work validates the feasibility of OPM-MMG system in animal models and provides a foundation for future applications in neuromuscular research, preclinical drug evaluation, and non-invasive electrophysiological diagnostics.