Non-neurotoxic Nanodiamond Probes for Intraneuronal Temperature Mapping

TL;DR

This study demonstrates that nanodiamonds with NV centers are non-toxic and can be used as stable, multi-functional intracellular sensors for high-resolution temperature mapping and potentially electrical activity detection in neurons.

Contribution

The paper introduces nanodiamonds as safe, effective intraneuronal probes capable of high-resolution temperature and magnetic sensing, expanding bio-imaging capabilities.

Findings

Nanodiamonds show no significant neurotoxicity over 12-36 hours.

NV centers enable enhanced magnetic resonance imaging.

Nanodiamonds facilitate nanoscale temperature mapping within neurons.

Abstract

Optical bio-markers have been used extensively for intracellular imaging with high spatial and temporal resolution. Extending the modality of these probes is a key driver in cell biology. In recent years, the NV centre in nanodiamond has emerged as a promising candidate for bio-imaging and bio-sensing with low cytotoxicity and stable photoluminescence. Here we study the electrophysiological effects of this quantum probe in primary cortical neurons. Multi-electrode array (MEA) recordings across five replicate studies showed no statistically significant difference in 25 network parameters when nanodiamonds are added at varying concentrations over various time periods 12-36 hr. The physiological validation motivates the second part of the study which demonstrates how the quantum properties of these biomarkers can be used to report intracellular information beyond their location and movement. Using the optically detected magnetic resonance from the nitrogen vacancy defects within the nanodiamonds we demonstrate enhanced signal-to-noise imaging and temperature mapping from thousands of nanodiamond probes simultaneously. This work establishes nanodiamonds as viable multi-functional intraneuronal sensors with nanoscale resolution, that may ultimately be used to detect magnetic and electrical activity at the membrane level in excitable cellular systems.