Understanding the human brain remains one of the most significant challenges of the 21st century. As theoretical studies continue to improve the description of the complex mechanisms that regulate biological processes, in parallel numerous experiment
s are conducted to enrich or verify these theoretical predictions and with the aim of extrapolating more accurate models. In the field of magnetometers for biological application, among the various sensors proposed for this purpose, NV centers have emerged as a promising solution due to their perfect biocompatibility and the possibility of being positioned in close proximity and even inside the cell, allowing a nanometric spatial resolution. There are still many difficulties that must be overcome in order to obtain both spatial resolution and sensitivity capable of revealing the very weak biological electromagnetic fields generated by neurons (or other cells). However, over the last few years, significant improvements have been achieved in this direction, thanks to the use of innovative techniques, which allow us to hope for an early application of these sensors for the measurement of fields such as the one generated by cardiac tissue, if not, in perspective, for the nerve fibers fields. In this review, we will analyze the new results regarding the application of NV centers and we will discuss the main challenges that currently prevent these quantum sensors from reaching their full potential.
The possibility of using Nitrogen-vacancy centers in diamonds to measure nanoscale magnetic fields with unprecedented sensitivity is one of the most significant achievements of quantum sensing. Here we present an innovative experimental set-up, showi
ng an achieved sensitivity comparable to the state of the art ODMR protocols if the sensing volume is taken into account. The apparatus allows magnetic sensing in biological samples such as individual cells, as it is characterized by a small sensing volume and full bio-compatibility. The sensitivity at different optical powers is studied to extend this technique to the intercellular scale.
