U.S. researchers develop ultra-sensitive probes that can hear cell beats

[China Instrument Network Instrument Development] The ultra-sensitive nano-probe is placed in the culture fluid of mouse cardiomyocytes. It can detect the beating of cardiac muscle cells, which is lower than the weakest volume the human ear can hear. Times.

Researchers at the University of California, San Diego, have developed an ultra-sensitive detection device that is 10 times more sensitive than atomic force microscopy and can collect and quantify weak forces and sounds. Their paper published in the journal Nature Photonics on the 15th said that the device can sense the power of bacterial movement and can "listen" to the heartbeat of heart cells.

The device is a nanofiber with a diameter of only one percent of human hair. It is made of extremely thin tin dioxide fiber, coated with a thin layer of polyethylene glycol and embedded with gold nanoparticles. The working principle is: When irradiated with light, gold nanoparticles interact with light and scatter light. These light signals appear with a certain intensity and can be observed with a conventional microscope. When the fiber is placed in a solution containing living cells, the force or sound waves from the cell can hit the gold nanoparticles and push them into the PEG coating, which is closer to the fiber and the interaction between the particles and the light becomes stronger The resulting light signal will be stronger. By analyzing the light signal, researchers can detect the strength of the fiber or the sound picked up by the fiber from the surrounding cells.

When this device is placed in a solution containing live Helicobacter pylori, it can detect 160 Newtons (10 trillionths of a Newton) of force, which is the power of Helicobacter pylori moving in the intestine. If placed in the culture fluid of mouse cardiomyocytes, it can detect the beating of cardiac muscle cells, which is 1000 times lower than the weakest volume the human ear can hear.

The key to this device is the polyethylene glycol coating, which acts like a spring pad and must be sensitive enough to be compressed to a different thickness by the weak forces or sound waves generated by the cells. This coating is adjustable: if you want to measure a larger force, you can use a harder coating; if the force to be measured is small, you can use a softer coating like a hydrogel.

The researchers said that as an ultra-sensitive nano-mechanical detection tool, the new device provides strong support for the study of some weak forces. Not only does it collect weak forces and sounds, it can also quantify them; not only is it more sensitive than AFM but it is also smaller than AFM. They plan to use such nanofibers to measure the biological activity and mechanical behavior of individual cells; to improve the "hearing" of such fibers to create ultra-sensitive biological stethoscopes and to develop new imaging technologies.

There is a saying that people can hear well and say that they can hear the sound of falling petals. But compared with the shaking of bacterial flagella, the sound of the petals falling out is simply a blast. However, new technology is beyond the imagination of the ancients and it is hard to hear a thousand times more noise than the lower limit of hearing. And the principle is so clever that it can be used to make a detection line with plastic, gold and tin rust. Cannot be praised by people.

(Original Title: Nanofibers that can sense the force and sound emitted by cells)