Researchers at Kanazawa University report at ACS Nano the development of a nanoparticle that works as a heater and thermometer. The introduction of nanoparticles into living cells (Heat up the hand, one cell at a time) creates a temperature that, by turning it on and off, allows the control of local cellular activity.
Being able to heat nanoscale regions in living tissue is key to many biomedical applications. In fact, many biological systems are temperature sensitive, and the ability to change temperature in a region provides a way to change cellular function. The obvious goal is to destroy cancer cells by burning them. In addition to the need for a local heating system in the body, it is also important to be able to measure the temperature directly. Satoshi Arai of Kanazawa University and his colleagues have developed a nanoparticle that is both a nanoheater and a nanothermometer. They have proven that applying a controlled temperature to the tissue can be very effective in changing cell function.
The nanoparticle, which scientists call “nanoHT” – short for “nanoheater-thermometer” – is actually a polymer matrix that embeds a dye molecule (called EuDT) that detects temperature, and more dyes (called V-Nc) to release Heat. The latter is done by the conversion of light into thermal energy (photothermal effect, which is also exploited in solar cells): shining a near-infrared laser (with a wavelength of 808 nanometers) at V-Nc and -produces faster heat, and more heat. rise for higher laser power.
Temperature detection is based on the thermal sensitivity of EuDT. When exposed to light of one wavelength, the molecule emits light of another wavelength – fluorescence. The higher the temperature, the stronger the fire becomes. This dynamic relationship can be used to measure temperature. Arai and his colleagues tested the performance of the nanoHT as a thermometer and found that it can determine the temperature with a resolution of 0.8 °C and less.
The researchers then conducted experiments on a type of human cell called HeLa cells. They investigated the effects of nanoHT heating and found that at a temperature increase of about 11.4 °C, heated HeLa cells died after only a few seconds. This research shows that nanoHT can be used to induce cell death in cancer cells.
Arai and his colleagues also investigated how nanoHT might affect health behavior. They introduced the nanoparticle into the myotube, a type of fiber found in the body. After the myotube is heated to about 10.5 °C, the tissue is assembled. The system works in a flexible manner; allowing the myotube to contract again caused the body to pause.
The work of Arai and colleagues shows that local and subcellular heating using nanoHT allows for the control of the activity of a single cell. Regarding the application, the scientists believe that “the targeted application of nanoHT has a unique and diverse ability to regulate cellular activity that will lead to the development of thermodynamic cellular engineering.”
Background
Fluorescence
Fluorescence refers to the emission of light from a substance after which it absorbs light (or another form of electromagnetic radiation). Normally, the light emitted has a longer wavelength, and therefore a lower photon energy, than the radiation that hits your heart. The well-known phenomenon of fluorescence occurs when radiation is absorbed in the ultraviolet region of the spectrum, which is invisible to the human eye, while bright light is in this region. is visible.
Fluorescent light is a method for measuring temperature using light-emitting molecules, the intensity of which depends on the temperature. Particles of the filter are added to the material of interest; Detailed information of fluorescence intensity vs. dependence on temperature makes it possible to determine the temperature of the material. (The cells in the dye are excited to glow from the incident light; its intensity provides a measure of the temperature of the area.)
Satoshi Arai of Kanazawa University and his colleagues used fluorescent molecules to create nanoHT, a nanoparticle that acts as a heat exchanger and thermometer for nano-bio applications.
