Scientists from LETI and St. Petersburg State University have found a new promising source of magnetic biocompatible nanoparticles that can be used in medicine for targeted drug delivery. Such particles are found in the shells of marine unicellular organisms - foraminifera. The press service of LETI reported this to RT. The results of the study were published in the proceedings of the Biogenic—Abiogenic Interactions in Natural and Anthropogenic Systems 2022 conference.

Foraminifera are predominantly marine single-celled organisms measuring 0.1–1 mm in size. Some species inhabit the bottom layers, and some live in the thickness of sea water. All of them have an external skeleton - a calcareous shell, which may also contain nano-sized inclusions of metals and their oxides, in particular iron.

In the new work, experts examined samples of foraminiferal shells that were obtained during expeditions of the research vessel “Professor Logachev” of the NPP “Polar Marine Geological Exploration Expedition” to the region of the Mid-Atlantic Ridge (Atlantic Ocean). In addition to information about the seabed, a large number of samples of local biota were collected, including local foraminifera.

  • Foraminifera

  • Legion-Media

  • © Imago_v1

Using the magnetic separation method, scientists selected unicellular shells that contained ferrimagnetic inclusions, including magnetite. Scientists studied the properties of iron-containing samples using optical and electron microscopy, X-ray diffractometry, and vibration magnetometry.

“The results of the study of these samples showed that they include, among other things, nanoparticles that have so-called superparamagnetic properties, and therefore in the future they may find application in solving problems of personalized medicine, nanoelectronics and others,” explained RT doctoral student, associate professor of the department of micro - and nanoelectronics (MNE) SPbSETU "LETI" Kamil Gareev.

Let us recall that superparamagnetism is a form of magnetism of ferromagnetic and ferrimagnetic particles. It is superparamagnetic nanoparticles that are used in medicine for diagnosis and targeted treatment of diseases. As the authors of the study suggest, magnetic nanoparticles of natural origin can be superior to artificially synthesized analogues in a number of parameters, primarily biocompatibility.

“Biogenic iron minerals with ferrimagnetic properties are found in many living organisms: magnetotactic bacteria (able to navigate by a magnetic field

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RT

), some types of protists (algae and protozoa) and eukaryotes (insects, mollusks, fish, birds and mammals). They participate in the processes of magnetotaxis, as a means for storing iron, for strengthening tissues,” Elena Sergienko, associate professor of the Department of Earth Physics at St. Petersburg State University, explained to RT.

According to her, if the mechanism of magnetite formation in magnetotactic bacteria is well studied and known, then exactly how such inclusions are formed in foraminifera is still unclear to science. However, this will not prevent us from finding practical applications for biogenic nanoparticles.