Biosensors for the youngest
Microsensors evaluate health by blood acidity
Scientists from the Research Institute of Biology of Irkutsk State University together with colleagues from Finland and Singapore have created microsensors that begin to fluoresce when the acidity of the blood changes, and an accurate diagnosis can be made by the spectrum of their glow.
The research groups of Maxim Timofeev (Irkutsk), Igor Meglinsky (University of Oulu, Finland) and Anton Sadovoy (Singapore) have created implantable microsensors in the form of semi-permeable microscopic capsules filled with special dye. With an increase in the acidity of the blood (pH), the appearance of certain ions, metabolites and hormones in it, they began to glow. The sensors are designed so that they can be injected even into the body of very small laboratory animals.
Biologists experimentally tested their development. They introduced capsules with fluorescent dye into the body of the danio-rerio fish. Its sensitive microparticles got into the bloodstream of animals and spread throughout the circulatory system. The scientists then placed the fish under a fluorescent microscope with a spectrometer. With their help, they took the fluorescence spectra of microsensors in the capillaries of fish, and then translated them into acidity values.
The acidity of the blood is a very important indicator that can tell about the general condition of the body. For example, in fish with a normal physiological state, the pH fluctuates around 7.7−7.8 (the neutral pH value is seven, that is, the pH of fish blood is slightly alkaline). The change in acidity indicates the presence of health problems. So, with hypoxia (lack of oxygen), carbon dioxide accumulates in the blood, which reduces the pH.
The new sensors made it possible to track how the blood acidity index changes in the body of fish. In the normal state of the zebrafish, the sensors recorded a pH in the region of 7.3-7.5 − such relatively small deviations from the average are normal for this type of fish. However, if the experimental fish fell into a coma, the pH decreased to values of about 6.8−7.0.
By studying small animals, which include developing fish embryos, you can learn about a variety of disorders in the work of the vertebrate organism (including humans), as well as the toxicity of new chemical compounds, such as medicines and cosmetics. Such studies, however, require a huge number of biological analyses. Therefore, a simple, cheap and widely used method that would allow you to track physiological parameters is now in great demand.
Russian scientists emphasize that this is only the first step in the development of such microsensors. It is necessary to move from small, almost transparent laboratory animals to agricultural breeds and, in the future, to humans.
An article describing the development was published in the journal PLOS ONE.
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