Nano Diamond "Thermometer"

Nanodiamonds can be used in quantum computers to process quantum information, and researchers at Harvard use the quantum effects of nanodiamonds to turn them into “thermometers” that measure the temperature changes inside human embryonic stem cells. Accuracy is the state of the art. 10 times. By adding gold nanoparticles, researchers can also use lasers to heat and even kill cells in specific parts of the cell, which is expected to provide a new way to treat cancer without damaging healthy tissue, as well as new ways to study cell behavior. Research papers were published this week in the journal Nature.

In this latest study, researchers used nanowires to inject diamond crystals with a diameter of about 100 nanometers into a human embryonic stem cell, and then irradiated the cells with a green laser so that nitrogen impurities emit red fluorescence. When the intracellular local temperature changes, the intensity of red fluorescence will be affected. By measuring the intensity of the fluorescence, the temperature of the corresponding nanodiamond can be calculated. Because the diamond has good thermal conductivity, it can show the immediate temperature of the cell's internal environment like a thermometer.

The researchers also injected gold nanoparticles into the cells, and then used lasers to heat different parts of the cells. The choice of the heating point and the temperature increase were precisely controlled by the nanodiamond "thermometer." "Now we have a tool that can control temperature at the cellular level, allowing us to study the biological system's response to temperature changes," said Peter Maurer, a physicist at Harvard who participated in the study.

He pointed out that many biological processes involved in basic biology, from gene expression to cell metabolism, will be strongly influenced by temperature, nano-diamond "thermometer" will be a useful tool. For example, by controlling the local temperature of nematodes, biologists can understand the development of simple organisms. "You can heat a single cell and study whether the cells around it will slow or accelerate their reproduction," Maurer said.

There are also other methods for measuring cell temperature, such as the use of fluorescent proteins or carbon nanotubes, but these measurement methods are deficient in sensitivity and accuracy, because some of the components react with substances in cells. Maurer said that their nanometer-diamond "thermometers" have at least a 10x increase in sensitivity and can detect temperature fluctuations as fine as 0.05. And there is room for improvement because the sensitivity of the "thermometer" has reached a temperature fluctuation of 0.0018 on the outside of living cells.