What Are Nanoparticles?

Nanoparticles refer to particles with a particle size between 1-100nm (nanoparticles are also called ultrafine particles). It belongs to the category of colloidal particle size. They are in the transition zone between atom clusters and macroscopic objects, between the microscopic system and the macroscopic system, and they are a group composed of a small number of atoms or molecules. Therefore, they are neither typical microscopic systems nor typical macroscopic systems.

Nanoparticles

It is foreseeable that nanoparticles should have some new physico-chemical properties. The feature that distinguishes a nanoparticle from a macroscopic object is that it has a large surface area, and the surface

Ultrasound self-assembly method Using the assistance of ultrasonic waves, substances interact with each other to form nanoparticles. Its characteristics are simple operation, but the experimental conditions are strict, and the selected raw materials must have two groups (hydrophilic group and lipophilic group).
Vapor deposition Synthesis of nanomaterials by chemical reaction of metal compound vapor. Its characteristics are high product purity and narrow particle size distribution.
Precipitation method -After adding a precipitating agent to a salt solution for reaction, the precipitation is heat-treated to obtain nanomaterials. Its characteristics are simple and easy, but low purity and large particle radius.
Hydrothermal synthesis method synthesis in a fluid such as aqueous solution or steam under high temperature and pressure, and then separate and heat treatment to obtain nanoparticles. Its characteristics are high purity, good dispersibility and easy control of particle size.
Sol-gel method -metal compounds are solidified by solution, sol, and gel, and then subjected to low heat treatment to generate nanoparticles. It is characterized by multiple reactive species, uniform product particles, and easy to control processes.
Microemulsion method -two immiscible solvents form an emulsion under the action of a surfactant. Nanoparticles are obtained after nucleation, coalescence, agglomeration and heat treatment in microbubbles. It is characterized by the monodispersity and good interfaciality of the particles. ^[1]

Nanoparticles have many active centers on the surface, which provides the necessary conditions for nanoparticles to be used as catalysts. Currently, nanoparticles are used

The magnetic nanoparticles developed by the University of Buffalo research team are only 6 nanometers in size and can easily diffuse between cells. The researchers first immobilized the nanoparticles on the cell membrane and then heated them with a high-frequency magnetic field to stimulate the cells. Since this method can stimulate cells uniformly over a wide range, scientists believe that the method can be applied in the human body in the future.

Researchers have now shown that the method can open calcium channels, activate nerve cells cultured through cells, and even manipulate the movement of tiny nematodes. When researchers fixed magnetic nanoparticles on the worm's mouth, they started to crawl around. However, when scientists heated the magnetic nanoparticles to 34 degrees Celsius, they were able to control the advance and retreat of nematodes.

The research team also invented a fluorescent probe that can measure whether the nanoparticles are heated to 34 degrees Celsius according to the change in fluorescence intensity. This fluorescent probe can be said to be a nano thermometer.

The research has a wide range of applications. For example, in cancer treatment, scientists can remotely operate on selected proteins or specific tissues to develop new cancer treatments. In addition, in the treatment of diabetes, pancreatic cells can be remotely stimulated to release insulin. The method can also be applied to certain neurological diseases caused by insufficient stimulation.

Scientists say this method is very important, because it only heats the cell membrane, and the temperature inside the cell does not change, so it does not cause cell death. By developing this method, scientists can use magnetic fields to stimulate cells in vitro and in vivo, help understand the cell's signal network, and control animal behavior.