KANAZAWA, Japan, July 4, 2022 / PRNewswire / – Researchers at Kanazawa University report a ACS Nano the development of a nanoparticle that acts as a heater and thermometer. The insertion of the nanoparticle into living cells results in a heat point that, by turning it on and off, allows controlled modulation of local cellular activities.
Being able to heat nanometer-sized regions in biological tissues is key to several biomedical applications. In fact, many biological processes are temperature sensitive and the ability to locally modify temperature provides a way to manipulate cellular activity. A notable purpose is the destruction of cancer cells by heating them. In addition to the need for a local heating mechanism in the tissue, it is also important to be able to instantly measure the temperature generated. Satoshi Arai of Kanazawa University and his colleagues have now designed a nanoparticle that is both a nanoheater and a nanothermometer at the same time. They successfully demonstrated that the insertion of a single controllable heat point into tissue can be very effective in modifying cell function.
The nanoparticle, called “nanoHT” by scientists, an abbreviation for “nanoheater-thermometer”, is essentially a polymer matrix that embeds a dye molecule (called EuDT) that is used to detect temperature and another dye molecule ( called V-Nc) to release. heat. The latter involves the conversion of light into thermal energy (the photothermal effect, also used in solar cells): the brightness of a near infrared laser (with a wavelength of 808 nanometers) on V-Nc causes rapid heating, with a stronger increase. in temperature for higher laser power.
Temperature detection is based on the thermal fluorescence effect of EuDT. When it radiates with light of one wavelength, the molecule emits light at another wavelength: fluorescence. The higher the temperature, the less intense the fluorescence. This inverse relationship can be used to measure temperature. Arai and colleagues tested the performance of the nanoHT as a thermometer and established that it can determine temperatures with a resolution of 0.8 ° C and below.
The researchers then performed experiments with a type of human cell called HeLa cells. They observed the effect of heating using nanoHT and found that at a temperature increase of about 11.4 ° C, heated HeLa cells died after only a few seconds. This finding suggests that nanoHT could be used to induce cell death in cancer cells.
Arai and colleagues also studied how nanoHT can be used to affect muscle behavior. They introduced the nanoparticle into the myotube, a type of fiber present in muscle tissue. By heating the myotube about 10.5 ° C, the muscle tissue contracted. The procedure worked reversibly; letting the myotube cool again caused muscle relaxation.
The work of Arai and colleagues shows that local heating at the subcellular scale using nanoHT allows controlled manipulation of single-cell activity. In terms of applications, scientists believe that “the specific application of nanoHT has a diverse and versatile range of capabilities to regulate cellular activities that would facilitate the development of thermodynamic cell engineering.”
Fund
Fluorescence
Fluorescence refers to the emission of light by a substance after which it has absorbed light (or another type of electromagnetic radiation). Normally, the emitted light has a longer wavelength, and therefore a lower photonic energy, than the absorbed radiation. A known case of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the spectrum, invisible to the human eye, while the emitted light is in the visible region.
Fluorescent thermometry is a technique for measuring temperatures by using fluorescent dye molecules, the fluorescence intensity of which is a strong function of temperature. Dye molecules are inserted into a material of interest; the detailed knowledge of the intensity of the fluorescence in function of the dependence of the temperature allows to infer the temperature of the material. (Dye molecules are fluorescent-excited by incident light; their intensity provides a measure of local temperature.)
Satoshi Arai of Kanazawa University and colleagues used fluorescence dye molecules to develop nanoHT, a nanoparticle that acts as a heater and thermometer for nanobio applications.
Reference
Ferdinandus, Madoka Suzuki, Cong Quang Vu, Yoshie Harada, Satya Ranjan Sarker, Shin’ichi Ishiwata, Tetsuya Kitaguchi and Satoshi Arai. Modulation of local cellular activities using a subcell-sized heat point based on photothermal dyes, ACS Nano 169004–9018 (2022).
DOI: 10.1021 / acsnano.2c00285
URL:
Images
Figure 1. Thermodynamic cell engineering: the creation of a small heat point allows to regulate cellular functions
Figure 2. Microscopic nanoheating system. A) Schematic and microscopic images of nanoheater (nanoHT) (transmission electron microscopy). B) A system for heating a region located at a single cellular level (top panel). A single nanoHT point was located within a single cell (bottom left panel). The microscale temperature gradient was generated at the subcellular level (lower right panel).
Figure 3. A nanoparticle that combines photothermal heating and fluorescence thermometry functions as a localized heat point, and is capable of inducing cell death or muscle contraction.
Contact
Hiroe Yoneda Deputy Director of Public Affairs WPI Nano Life Science Institute (WPI-NanoLSI) Kanazawa UniversityKakuma-machi, Kanazawa 920-1192, JapanE-mail: [email protected]Tel: +81 (76) 234-4550
About Nano Life Science Institute (WPI-NanoLSI)
Nano Life Science Institute (NanoLSI), Kanazawa University is a research center established in 2017 as part of the International Research Center Initiative of the Ministry of Education, Culture, Sports, Science and Technology. The aim of this initiative is to form world-class research centers. NanoLSI combines the most important knowledge of bio-scanning probe microscopy to establish “nano-endoscopic techniques” by imaging, directly analyzing and manipulating biomolecules to understand the mechanisms that govern life phenomena such as disease.
About Kanazawa University
As a leading comprehensive university on the Sea Coast of Japan, Kanazawa University has contributed greatly to higher education and academic research in Japan since it was founded in 1949. The University has three colleges and 17 schools. offering courses in subjects including medicine, computer engineering. , and humanities.
The University is located on the sea coast of Japan in Kanazawa, a city rich in history and culture. The city of Kanazawa has a highly respected intellectual profile since the time of the feud (1598-1867). Kanazawa University is divided into two main campuses: Kakuma and Takaramachi for its approximately 10,200 students, including 600 from abroad.
SOURCE University of Kanazawa