Nanodiamond Theranostic for Light-Controlled Intracellular Heating and Nanoscale Temperature Sensing

Abstract

Temperature is an essential parameter in all biological systems, but information about the actual temperature in living cells is limited. Especially, in photothermal therapy, local intracellular temperature changes induce cell death but the local temperature gradients are not known. Highly sensitive nanothermometers would be required to measure and report local temperature changes independent of the intracellular environment, including pH or ions. Fluorescent nanodiamonds (ND) enable temperature sensing at the nanoscale independent of external conditions. Herein, we prepare ND nanothermometers coated with a nanogel shell and the photothermal agent indocyanine green serves as a heat generator and sensor. Upon irradiation, programmed cell death was induced in cancer cells with high spatial control. In parallel, the increase in local temperature was recorded by the ND nanothermometers. This approach represents a great step forward to record local temperature changes in different cellular environments inside cells and correlate these with thermal biology.

Silicon-Vacancy Nanodiamonds as High Performance Near-Infrared Emitters for Live-Cell Dual-Color Imaging and Thermometry

“… 10 In the same work, a change in the intensity of SiV fluorescence in NDs with a size of 200 nm is shown. NDs with NV are used for intracellular thermometry, 28 but such experiments require microwave field while SiV offers pure optical measurements. However, NDs with SiV have not been tested yet for thermometry by ZPL shift measurements.…”

Nanodiamonds based optical-fiber quantum probe for magnetic field and biological sensing

“…Figure 3(a) indicates that as the increase of magnetic field variation, all the spectral lines are centered at 2.87 GHz while shifting to the both sides, which corresponds to the magnetic-field-induced split between |+1> and |-1> of NV ground stage. The center frequency v 0 , corresponding to the zero-field split between |0> and |±1>, is temperature-dependent with a constant of about -74 kHz/K 29 . During test, v 0 almost remains unchanged for each probe with a maximal fluctuation of 0.16 MHz, suggesting a temperature variation of 2.2 K [Figure S1(a)].…”

Intracellular thermometry uncovers spontaneous thermogenesis and associated thermal signaling

“…The use of intracellular thermometric technology is expected to advance research areas; 1. thermal medicine 61 , which explores the manipulation of body or tissue temperature for the treatment of disease, including theragnostics 62 , and 2. thermal biology, which consists of the measurement of intracellular temperature variations within individuals and the determination of temperature-sensing and temperature-maintaining mechanisms at the individual and single-cell levels. In particular, we are paying close attention to “thermal signaling” in the latter field, which is a signal transduction system utilizing temperature changes in the body as input, exemplified by the molecular switch that transitions cellular energy metabolism to heat production 48 and by TRPV4, which is activated by spontaneous temperature increases in its residing cell 51 .…”