Laser stimulation of muscle activity with simultaneous detection using a diamond colour centre biosensor

TL;DR

This paper demonstrates a noninvasive, diamond-based biosensor capable of detecting localized neuromuscular activity induced by laser stimulation, advancing passive imaging of biological systems without artifacts.

Contribution

It introduces the use of diamond color center biosensors for noninvasive, in-vitro detection of laser-induced neuromuscular activity, a novel approach in biosensing technology.

Findings

Successfully recorded magnetic signals from laser-stimulated muscles

Detected both compound action potentials and slow signals

Sensor operated without photovoltaic or fluorescence artifacts

Abstract

The detection of physiological activity at the microscopic level is key for understanding the function of biosystems and relating this to physical structure. Current sensing methods often rely on invasive probes to stimulate and detect activity, bearing the risk of inducing damage in the target system. In recent years, a new type of biosensor based on color centers in diamond offers the possibility to passively, noninvasively sense and image living biological systems. Here, we use such a sensor for the \textit{in-vitro} recording of the local magnetic field generated by tightly focused, high intensity pulsed laser optogenetic neuromuscular stimulation of the extensor digitorum longus muscles. Recordings captured a compound action potential response and a slow signal component which we seek to explain using a detailed model of the biological system. We show that our sensor is capable of recording localized neuromuscular activity from the laser stimulation site without photovoltaic or fluorescence artifacts associated with alternative techniques. Our work represents an important step towards selective induction of localized neurobiological activity while performing passive sensing and imaging with diamond sensors, motivating further research into mapping of neural activity and intra-cellular processes.