EPJ Quantum Technol. (2020) 7: 13
https://doi.org/10.1140/epjqt/s40507-020-00088-2

Research

A biocompatible technique for magnetic field sensing at (sub)cellular scale using Nitrogen-Vacancy centers

¹ Istituto Nazionale di Ricerca Metrologica, Strada delle cacce 91, Turin, Italy
² Physics Department and NIS Centre of Excellence, University of Torino, Turin, Italy
³ Istituto Nazionale di Fisica Nucleare (INFN) Sez. Torino, Turin, Italy
⁴ Centre for Accelerator Science, Australian Nuclear Science and Technology Organisation, New Illawarra rd., Lucas Heights, Australia

^* e-mail: e.bernardi@inrim.it

Received: 18 June 2020
Accepted: 7 October 2020
Published online: 21 October 2020

Abstract

We present an innovative experimental set-up that uses Nitrogen-Vacancy centres in diamonds to measure magnetic fields with the sensitivity of $$\eta =68\pm 3\mathrm{nT}/\sqrt{\mathrm{Hz}}$$ at demonstrated (sub)cellular scale. The presented method of magnetic sensing, utilizing a lock-in based ODMR technique for the optical detection of microwave-driven spin resonances induced in NV centers, is characterized by the excellent magnetic sensitivity at such small scale and the full biocompatibility. The cellular scale is obtained using a NV-rich sensing layer of 15 nm thickness along z axis and a focused laser spot of (10 × 10) µm² in x-y plane. The biocompatibility derives from an accurate choice of the applied optical power. For this regard, we also report how the magnetic sensitivity changes for different applied laser power and discuss the limits of the sensitivity sustainable with biosystem at such small volume scale. As such, this method offers a whole range of research possibilities for biosciences.