Optically Detected Magnetic Resonance Based Intracellular Thermometry Using Nanodiamonds Implanted in Adherent Cancer Cells

Intracellular temperature influences cell metabolism and the tumor microenvironment, but there is a lack of consensus on basic thermal properties of cells and a shortage of reliable measurement tools. We utilized nanodiamonds (NDs) containing fluorescent Nitrogen Vacancy centers (NVs) implanted in glioblastoma cells to measure intracellular temperature via Optically Detected Magnetic Resonance (ODMR) and used dual fluorescence and bright-field imaging to establish ND-mitochondria distances. Careful ND selection, improved curve fitting, and time averaging enable repeatable measurement of cellular responses. Upon mitochondrial uncoupling with 5 μM FCCP, we reproducibly observed ODMR shifts consistent with an ∼1.7 °C temperature increase.