MOSCOW, October 10. Scientists from MIET as part of an international group were able to enhance the piezoelectric effect in glycine crystals. By mechanically polishing a modification of this amino acid, they say the piezoelectric response efficiency can be increased three to five times compared to conventional crystals. The work done is important for creating biocompatible small-sized electromechanical devices, the researchers explained. The results were published in Physica Scripta.
The development of micro- and nano-sized electrical devices compatible with the human body is an important area in high-tech medicine. For example, as studies have shown, electrical stimulation of cells accelerates wound healing, and the integration of electrical elements into various implants improves their controllability, said scientists from the National Research University «MIET» (MIET).
They explained that polymers are now used to make such electronics and composites that have a fairly high “affinity” with human tissues, but the closest to the body are those materials that are made from compounds present in large quantities in the human body.
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An example of such a substance is glycine, the simplest amino acid that is a neurotransmitter in the central nervous system and is present in many proteins of living organisms. In the solid state, this compound consists of crystals that can have different internal structures.
Some crystalline substances exhibit a piezoelectric effect, due to which they are able to conduct current when mechanical force is applied, such as compression. Also, in ordered structures, the movement of charged particles can form with increasing temperature — this effect is called ferroelectric, experts explained.
Researchers from MIET and MIREA, together with scientists from Portugal and the Netherlands, have developed a way to increase the electrical “efficiency” of γ-glycine crystals through local mechanical polishing.
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“Crystals polished at the molecular level demonstrated improved piezo- and ferroelectric activity and more efficient switching under the influence of an electric field,” explained Maxim Silibin, associate professor at the Institute of Advanced Materials and Technologies.
The researcher said that mechanical polishing of γ-glycine improves its piezoelectric properties, which in turn can lead to increased sensitivity of sensors and the efficiency of energy harvesting devices. The enhancement of the piezoelectric effect depends on the orientation of the applied pressure: for example, along one axis it increases threefold, along a perpendicular one — fivefold.
«Understanding and controlling the processes in γ-glycine crystals will make it possible to make devices for direct exchange of information with pulses nervous system and brain,” explained M.V.Silibin.
In the future, the research team from MIET and MIREA plans to conduct additional study of other mechanical or chemical methods for processing γ-glycine and similar materials to optimize their piezo- and ferroelectric properties .
MIET is a participant in the state support program for universities of the Russian Federation «Priority-2030» of the national project «Science and Universities».