Prof. Kristine Berg-Sorensen, Technical University of Denmark (DTU)

Nanodiamonds with color centers are to an increasing degree investigated as intracellular biosensors for magnetic fields, electrical fields, or temperature changes. A widespread color center is the nitrogen-vacancy center in which a substitutional nitrogen atom is positioned next to a vacancy within the diamond host crystal. In particular, the negatively charged NV- center has demonstrated its versatility, due to both its biocompatibility and its purely optical addressability. Apart from sensing magnetic fields or temperature, the NV- center has been applied to monitor abundance of free radicals and pH inside live cells.
In our work, we aim to apply the NV-center carrying nanodiamond both as an intracellular biosensor and as a probe particle within an optical trap, to determine viscoelastic properties of the intracellular medium, the cytoplasm, in single cell studies. For this to be successful, several prior steps are needed: 1) the uptake of nanodiamonds within the cells should be characterized and a controllable protocol developed; 2) any effect of the trapping laser on the NV-center sensing should be characterized and understood, and a protocol for stable trapping along with accurate biosensing developed.
The presentation will cover results and insight for both aspects, with two different cell types, and provide a roadmap for future development of in-cell NV center sensing modalities with optically trapped nanodiamonds.