Magnetometry of neurons using a superconducting qubit

TL;DR

This study demonstrates a superconducting qubit-based magnetometry technique capable of detecting electron spin signals from cultured neurons, paving the way for single-cell ESR spectroscopy.

Contribution

It introduces a novel method for neuron magnetometry using a superconducting flux qubit with potential for single-cell ESR analysis.

Findings

Detected neuron magnetization signals above control levels.

Identified electron spins of iron ions as the source.

Demonstrated feasibility of bio-spin detection at microscale.

Abstract

We demonstrate magnetometry of cultured neurons on a polymeric film using a superconducting flux qubit that works as a sensitive magnetometer in a microscale area. The neurons are cultured in Fe$^{3+}$ rich medium to increase magnetization signal generated by the electron spins originating from the ions. The magnetometry is performed by insulating the qubit device from the laden neurons with the polymeric film while keeping the distance between them around several micrometers. By changing temperature (12.5 - 200 mK) and a magnetic field (2.5 - 12.5 mT), we observe a clear magnetization signal from the neurons that is well above the control magnetometry of the polymeric film itself. From electron spin resonance (ESR) spectrum measured at 10 K, the magnetization signal is identified to originate from electron spins of iron ions in neurons. This technique to detect a bio-spin system can be extended to achieve ESR spectroscopy at the single-cell level, which will give the spectroscopic fingerprint of cells.