Biogenic Magnetic Nanoparticles Research Articles

A new green system of biogenic Ni/DFNS@Pd nanoparticles for the production of 2-oxo-2-phenylethylbenzoate and cyclic carbonates by using the oxidative carboxylation of alkenes

In this paper, we report highly atom-selective and efficacious oxidation of styrenes with carbon dioxide to cyclic carbonates in the appearance of Ni/[email protected] as a magnetic nanocatalyst (MNPs). For convenient detachment of the catalyst by an exterior magnetic domain, the dendritic fibrous nanosilica (DFNS) outer layer was covered with nickel to magnetize the DFNS. Then, the palladium nanoparticles on the outer layer of Ni/DFNS were diminished. In spite of the possibility of using these biological processes in the sustainable recapturing of vital metals (e.g. Pd), the catalytic function of biosynthesised MNPs has not yet been scrutinized. Here, instead of a chemical approach, microorganisms were utilized as catalysts for the generation of Pd nanoparticles in a biological procedure. These biogenic magnetic nanoparticles have been utilized for the first time as a reusable catalyst with an exterior magnet. The catalyst’s attributes were distinguished by a variety of methods, including scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and vibrating sample magnetometer (VSM) analyses. Biogenized Ni/[email protected] was generated as a heterogeneous catalyst to compete with a homogeneous structure. This robust metal catalyst with great accessibility level and reusability was generated by anaerobic bacteria. Examining different concentrations of the catalyst showed that the selectivity and efficiency of the reaction are significantly affected by the concentration of the catalyst. Heterogeneous reaction compounds did not cause any negative effects. The products were eliminated from the catalyst without any problems and the catalyst was employed many times without a conspicuous loss in selectivity and activity.

Effect of oscillating magnetic fields on freezing of a colloidal dispersion of superparamagnetic nanoparticles

Several studies suggest that single-domain biogenic magnetic nanoparticles could play a major role on the effectiveness of oscillating magnetic fields (OMFs) in improving food freezing. To evaluate the potential role of superparamagnetic biogenic particles, we performed freezing experiments in a colloidal dispersion of <10-nm maghemite nanoparticles (MNPs) subjected or not to a 31.3-mT OMF at 50 Hz. Our results show that, at our experimental conditions, Néel mechanism governs the alignment of magnetic dipole moments and, therefore, no significant MNPs rotation, able to disturb the ordering of water molecules, should be expected during OMF experiments. Accordingly, no effects of the applied OMF were observed either on supercooling, ice nucleation, or on freezing kinetics even though heat removal was slightly increased during the precooling step. These results suggest that weak OMFs usually applied in commercial freezers should not produce any significant effect on superparamagnetic nanoparticles present in food that could improve the freezing process.

Magnetic and structural properties of biogenic magnetic nanoparticles along their production process for use in magnetic hyperthermia

Iron-oxide nanoparticles synthesized by magnetotactic bacteria can be used in cancer treatment by means of magnetic hyperthermia. In order to study the structural properties of samples through the successive steps of their production from cultivated magnetotactic bacteria to coated magnetosomes, and their effect on magnetic properties, we performed a combination of (cryo-)Transmission Electron Microscopy observations and magnetic hysteresis as well as First-Order Reversal Curve diagrams at low temperature. The anisotropy of magnetic interactions was investigated by recording field-cooled FORC diagrams with a measuring field either parallel or perpendicular to the field-cooling direction. The results from the various techniques are in very good agreement. We found that magnetosomes in magnetotactic bacteria are arranged in chains and have magnetic properties typical of stable single-domain aligned particles. Extracted magnetosomes form clusters of interacting maghemite particles with some remaining chains, while purified magnetosomes are solely arranged in clusters. Finally, magnetosomes coated with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) are still organized in clusters but with less magnetostatic interactions than in purified magnetosomes, while magnetosomes coated with citric acid tend to recover a chained structure forming loops. The main features observed on the FORC diagrams are consistent with the various arrangement observed. Lastly, hyperthermia properties were measured for the two coated samples and we found that magnetosomes coated with citric acid display a higher Specific Absorption Rate and therefore hold a better potential for biomedical applications.

BIOGENIC AND ANTHROPOGENIC MAGNETIC NANOPARTICLES IN THE PHLOEM SIEVE TUBES OF PLANTS

The samples of leaves and roots of Nicotiana tabacum, the stems and tubers of Solanum tuberosum and the stems of pea Pisum sativum were examined by scanning probe microscopy in atomic force and magnetic force modes after cultivation without and with addition of magnetite nanoparticles in soil. Chains of both biogenic and anthropogenic magnetic nanoparticles are detected in the wall of the phloem sieve tubes i.e., the vascular tissue of plants. Such a localization of biogenic magnetic nanoparticles supports the idea that the chains of magnetic nanoparticles in different organs of plants have common metabolic functions. Stray gradient magnetic fields about several thousand Oe, which are created by chains of both biogenic and anthropogenic magnetic nanoparticles, can significantly affect the metabolic processes through the influence on mass transfer of vesicles, granules, organelles and other components. In view of the results of this investigation, both BMNs and anthropogenic magnetite nanoparticles chains can significantly affect the processes of mass transfer of vesicles, organelles, structural elements of the membrane and others components because they create stray magnetic fields and gradient magnetic forces.

Interaction of magnetic fields with biogenic magnetic nanoparticles on cell membranes: Physiological consequences for organisms in health and disease

The interaction mechanisms between magnetic fields (MFs) and living systems, which remained hidden for more than a hundred years, continue to attract the attention of researchers from various disciplines: physics, biology, medicine, and life sciences. Revealing these mechanisms at the cellular level would allow to understand complex cell systems and could help to explain and predict cell responses to MFs, intervene in organisms’ reactions to MFs of different strengths, directions, and spatial distributions. We suggest several new physical mechanisms of the MF impacts on endothelial and cancer cells by the MF interaction with chains of biogenic and non-biogenic magnetic nanoparticles on cell membranes. The revealed mechanisms can play a hitherto unexpected role in creating physiological responses of organisms to externally applied MFs. We have also a set of theoretical models that can predict how cells will individually and collectively respond to a MF exposure. The physiological sequences of the MF – cell interactions for organisms in health and disease are discussed. The described effects and their underlying mechanisms are general and should take place in a large family of biological effects of MFs. The results are of great importance for further developing novel approaches in cell biology, cell therapy and medicine.

Gradient Magnetic Field Accelerates Division of E. coli Nissle 1917.

Cell-cycle progression is regulated by numerous intricate endogenous mechanisms, among which intracellular forces and protein motors are central players. Although it seems unlikely that it is possible to speed up this molecular machinery by applying tiny external forces to the cell, we show that magnetic forcing of magnetosensitive bacteria reduces the duration of the mitotic phase. In such bacteria, the coupling of the cell cycle to the splitting of chains of biogenic magnetic nanoparticles (BMNs) provides a biological realization of such forcing. Using a static gradient magnetic field of a special spatial configuration, in probiotic bacteria E. coli Nissle 1917, we shortened the duration of the mitotic phase and thereby accelerated cell division. Thus, focused magnetic gradient forces exerted on the BMN chains allowed us to intervene in the processes of division and growth of bacteria. The proposed magnetic-based cell division regulation strategy can improve the efficiency of microbial cell factories and medical applications of magnetosensitive bacteria.

Bioinformatics Analysis of Protein Homologues of Magnetotactic Bacteria Magnetosome Island Proteins in Human Proteome

Background. The number of biogenic magnetic nanoparticles (BMN), present in human organs and tissues in the form of magnetite (ferrimagnetic iron oxide), increases in oncological and neurodegenerative diseases. Therefore, the study of homologues of BMN biomineralization proteins (mam-proteins) of magnetotaxis bacteria (MTB) in human proteome is relevant task. This concern is due primarily to the expediency of establishing patterns of changes in the expression of these proteins and searching for correlations with oncological and neurodegenerative diseases. Objective. We are aimed to conduct the bioinformatic analysis of homologues of MTB mam-proteins in humans and to determine the patterns of changes in the expression of these proteins, as well as to search for their connections with the specified diseases. This will allow to identify the main candidate proteins (among the known homologues of MTB mam-proteins in humans) for experimental verification of their participation in the genetically programmed mechanism of BMN biosynthesis in humans. Methods. The methods of comparative genomics were used, in particular the BLAST (Basic Local Alignment Search Tool) program of the NCBI database. Database tools were also used: NCBI Conserved Domain Search, The Cancer Genome Atlas database, Ensembl database. Results. The bioinformatic analysis of 16 homologues of MTB mam-proteins in humans was carried out, namely: PEX5, ANAPC7, CDC23, CDC27 and SGTA – homologues of MamA in MTB; SLC30A4, SLC30A9, SLC39A3 and SLC39A4 – homologs of MamB and MamM in MTB; HTRA1, HTRA2, HTRA3 and HTRA4 – MamO and MamE homologues in MTB; SCRIB, PDZK1 and PDZD3 – MamE homologues in MTB. Using pairwise alignments, the degree of homology between the mam-proteins of the MTB magnetosome island and the corresponding human proteins was determined, conserved domains and their functions were determined, changes in their expression levels in cancer and normal conditions were determined by analyzing the relevant databases, and the metabolic pathways to which the data proteins are involved were analysed. The analysis of the obtained data allowed to assume the presence of the main homologues of the MTB mam-proteins of the magnetosome island in humans, which cause an increase in the level of BMN in oncological and neurodegenerative diseases, namely: an increase in the expression level of the proteins PEX5, ANAPC7 (homologs of MamA), SLC39A3, SLC39A4 (homologs of MamB and MamM), HTRA4 (MamO and MamE homolog) and SCRIB (MamE homolog). Conclusions. The obtained data allow us to assume that the proteins PEX5, ANAPC7, SGTA, SLC39A3, SLC39A4, HTRA4 and SCRIB are the main homologues of the MTB mam-proteins in humans and cause an increase in the level of BMN in oncological and neurodegenerative diseases.

Biosensors and Drug Delivery in Oncotheranostics Using Inorganic Synthetic and Biogenic Magnetic Nanoparticles.

Magnetic nanocarriers have attracted attention in translational oncology due to their ability to be employed both for tumor diagnostics and therapy. This review summarizes data on applications of synthetic and biogenic magnetic nanoparticles (MNPs) in oncological theranostics and related areas. The basics of both types of MNPs including synthesis approaches, structure, and physicochemical properties are discussed. The properties of synthetic MNPs and biogenic MNPs are compared with regard to their antitumor therapeutic efficiency, diagnostic potential, biocompatibility, and cellular toxicity. The comparative analysis demonstrates that both synthetic and biogenic MNPs could be efficiently used for cancer theranostics, including biosensorics and drug delivery. At the same time, reduced toxicity of biogenic particles was noted, which makes them advantageous for in vivo applications, such as drug delivery, or MRI imaging of tumors. Adaptability to surface modification based on natural biochemical processes is also noted, as well as good compatibility with tumor cells and proliferation in them. Advances in the bionanotechnology field should lead to the implementation of MNPs in clinical trials.

Bioinformatic Analysis of the Genetic Mechanism of Biomineralization of Biogenic Magnetic Nanoparticles in Bacteria Capable of Tumor-Specific Accumulation

Background. Current methods of targeted cancer therapy are not always effective enough and can lead to side effects, such as an increased risk of autoimmune diseases. It is known that some bacteria are capable of specific accumulation in malignant tumors, and therefore can be used as an alternative means of targeted drug delivery. However, the genetic mechanism of tumor-specific accumulation of bacteria is not fully understood and needs to be studied in more detail. Objective. This work aims to identify, by methods of comparative genomics methods, magnetically controlled bacteria among those for which tumor-specific accumulation has already been experimentally shown. Methods. To identify magnetically controlled bacterial strains, i.e., bacteria that biomineralize biogenic magnetic nanoparticles (BMN), the method of comparative genomics was used, namely: pairwise alignment of proteomes with amino acid sequences of Mam-proteins of required for biomineralization of BMN in magneto­tactic bacteria Magnetospirillum gryphiswaldense MSR-1. Sequence alignments were performed in the BLAST program of the US National Center for Biotechnology Information (NCBI). Results. The conducted bioinformatic analysis showed that strains of bacteria in which the ability to accumulate specifically in tumors has been experimentally proven are potential producers of BMN of different types. Among them there are potential producers of intracellular crystalline BMN, potential producers of intracellular amorphous BMN, and extracellular crystalline BMN Conclusions. It is expedient to use bacteria-producing BMN as gene vectors and systems of targeted drug delivery to tumors that biomineralize BMN.

A Magnetosome-Based Platform for Flow Biocatalysis.

Biocatalysis in flow reactor systems is of increasing importance for the transformation of the chemical industry. However, the necessary immobilization of biocatalysts remains a challenge. We here demonstrate that biogenic magnetic nanoparticles, so-called magnetosomes, represent an attractive alternative for the development of nanoscale particle formulations to enable high and stable conversion rates in biocatalytic flow processes. In addition to their intriguing material characteristics, such as high crystallinity, stable magnetic moments, and narrow particle size distribution, magnetosomes offer the unbeatable advantage over chemically synthesized nanoparticles that foreign protein “cargo” can be immobilized on the enveloping membrane via genetic engineering and thus, stably presented on the particle surface. To exploit these advantages, we develop a modular connector system in which abundant magnetosome membrane anchors are genetically fused with SpyCatcher coupling groups, allowing efficient covalent coupling with complementary SpyTag-functionalized proteins. The versatility of this approach is demonstrated by immobilizing a dimeric phenolic acid decarboxylase to SpyCatcher magnetosomes. The functionalized magnetosomes outperform similarly functionalized commercial particles by exhibiting stable substrate conversion during a 60 h period, with an average space–time yield of 49.2 mmol L–1 h–1. Overall, our results demonstrate that SpyCatcher magnetosomes significantly expand the genetic toolbox for particle surface functionalization and increase their application potential as nano-biocatalysts.

Chain-Like Structures of Biogenic and Nonbiogenic Magnetic Nanoparticles in Vascular Tissues.

In this paper, slices of organs from various organisms (animals, plants, fungi) were investigated by using atomic force microscopy and magnetic force microscopy to identify common features of localization of both biogenic and nonbiogenic magnetic nanoparticles. It was revealed that both biogenic and nonbiogenic magnetic nanoparticles are localized in the form of chains of separate nanoparticles or chains of conglomerates of nanoparticles in the walls of the capillaries of animals and the walls of the conducting tissue of plants and fungi. Both biogenic and nonbiogenic magnetic nanoparticles are embedded as a part of the transport system in multicellular organisms. In connection with this, a new idea of the function of biogenic magnetic nanoparticles is discussed, that the chains of biogenic magnetic nanoparticles and chains of conglomerates of biogenic magnetic nanoparticles represent ferrimagnetic organelles of a specific purpose. Besides, magnetic dipole-dipole interaction of biogenic magnetic nanoparticles with magnetically labeled drugs or contrast agents for magnetic resonance imaging should be considered when designing the drug delivery and other medical systems because biogenic magnetic nanoparticles in capillary walls will serve as the trapping centers for the artificial magnetic nanoparticles. The aggregates of both artificial and biogenic magnetic nanoparticles can be formed, contributing to the risk of vascular occlusion. Bioelectromagnetics. 43:119-143, 2022. © 2021 Bioelectromagnetics Society.

The Effect of Magnetite Nanoparticles on the Growth and Development of Nicotiana Tabacum Plants in Vivo and in Vitro Culture

Background. Nanomaterials are easily modified and have unique characteristics associated with a large reactive surface Due to these properties, nanomaterials are used in various branches of sciences and technology, such as pharmaceuticals, biotechnology, chemical technology, etc. Recently, the effect of magnetite nanoparticles on the morphological properties of plants has been actively studied for their further use as nanoadditives to increase yields and improve the properties of agricultural plants. Tobacco (Nicotiana tabacum) is a model object of plant biotechnology, it is used to study the effect of various factors on dicotyledonous plants, so it was chosen to study the effect of magnetite on the growth, development, and mass accumulation by plants. Objective. We are aimed to study the effect of magnetite nanoparticles on the growth and development of Nicotiana tabacum in vivo and in vitro. Methods. The ability of tobacco to produce biogenic magnetic nanoparticles by searching for mammal proteins homologues in theNicotiana tabacum proteome using the Blast NCBI program was studied using comparative genomics methods. The plants were divided into groups (control, magnetite nanoparticle concentration 0.1 mg/cm3, magnetite nanoparticle concentration 1 mg/cm3) for both in vivo and in vitro experiments. Analysis of plant parameters was performed every 14 days to study the dynamics of the effects of magnetite nanoparticles. Results. It was determined that magnetite nanoparticles at a concentration of 0.1 mg/cm3 in culture in vitro and in vivo significantly affect the growth of the root system and sprouts of Nicotiana tabacum. On the 56th day of plant cultivation in vitro on a salivary medium supplemented with magnetite nanoparticles at a concentration of 0.1 mg/cm3, an increase in the shoot length by 13.3%, root length by 31.7%, and the mass of absolutely dry substances by 18.75% was observed compared to the control. Treatment of magnetite nanoparticles with a suspension at a concentration of 0.1 mg/cm3 led to more pronounced results when growing tobacco in vivo. So, on the56th day, the root length increased by 23.3%, the length of the shoot – by 19.2%, and the mass of absolutely dry substances – by2 times, the first leaves appeared 2 days earlier compared to the control. The addition of magnetite nanoparticles to the substrate on which the plants were grown in vivo at a concentration of 1 mg/cm3 inhibits the growth of tobacco. Conclusions. Studies have shown the expediency of using magnetic nanoparticles at a concentration of 0.1 mg/cm3 as nanofertilizers in tobacco cultivation.

Magnetosome membrane engineering to improve G protein-coupled receptor activities in the magnetosome display system

Magnetotactic bacterium, Magnetospirillum magneticum, produces biogenic magnetic nanoparticles termed magnetosomes, which are primarily composed of a magnetite core and a surrounding lipid bilayer membrane. We have fabricated human transmembrane protein-magnetosome complexes by genetic engineering with embedding the transmembrane proteins of interest, in particular G protein-coupled receptors (GPCRs), in the magnetosome membrane. The magnetosomes provide a promising platform for high throughput ligand screening towards drug discovery, and this is a critical advantage of the magnetosome display system beyond conventional membrane platforms such as liposomes and lipid nano-discs. However, the human GPCRs expressed on the magnetosomes were not fully functionalized in bacterial membranes the most probably due to the lack of essential phospholipids such as phosphatidylcholine (PC) for GPCR functionalization. To overcome this issue, we expressed two types of PC-producing enzymes, phosphatidylcholine synthase (PCS) and phosphatidylethanolamine N-methyltransferase (PMT) in M. magneticum. As a result, generation and incorporation of PC in cell- and magnetosome-membranes were demonstrated. To the best of our knowledge, M. magneticum is the second bacterial species which had the PC-incorporated lipid membrane by genetic engineering. Subsequently, a GPCR, thyroid-stimulating hormone receptor (TSHR) and PCS were simultaneously expressed. We found that PC in the magnetosome membrane assisted the binding of TSHR and its ligand, indicating that the genetic approach demonstrated in this study is useful to enhance the function of the GPCRs displayed on the magnetosomes.

The influence of artificial and biogenic magnetic nanoparticles on the metabolism of fungi

The influence of artificial and biogenic magnetic nanoparticles on the metabolism of fungi

An efficient base and H2O2 free protocol for the synthesis of phenols in water and oxygen using spinel CuFe2O4 magnetic nanoparticles

An efficient base and H2O2 free protocol was used for the synthesis of phenols from boronic acids using biogenic CuFe2O4 magnetic nanoparticles as catalyst at room temperature in water and oxygen. The catalyst was prepared using the flowers of Lantana camara. The size of the nanoparticles was 4.27 nm. Base free and ligand free protocol, less time, excellent yields, room temperature, biogenic synthesis of the catalyst, use of O2 as an environmentally friendly oxidant are the advantages of the present protocol. The recyclability of the catalyst was for 5 cycles without loss of magnetic property or catalytic activity.

Production of Magnetically Controlled Biosorbents Based on Fungi Pleurotus ostreatus

Background. Biogenic magnetic nanoparticles (BMN) have been found in representatives of all three superkingdoms of living organisms: bacteria, archaea and eukaryotes (including fungi). At the same time, it was established that the mechanism of biomineralization of BMN is unique for all living organisms. The search for sorbents of biological origin has become one of promising ways of addressing the problem of environmental pollution by heavy metals. Heavy metals are elements of transport emissions and many factories in various industries. These metals getting into the human body cause significant disruption of metabolism and vital functions of the body. Many macromycetes are known to be natural sorbents for heavy metal ions. Laboratory tests use a method of filtering spent sorbent through a paper filter, which is long enough and inefficient. Therefore, it is important to find a more effective way of removing biosorbent from the solution. Such a cheap and efficient method is high-speed magnetic gradient separation. Objective. The aim of the paper is to obtain a magnetically controlled biosorbent based on a fungus Pleurotus ostreatus , to determine the fraction of the magnetically controlled phase of the fungus biomass when added to the substrate of the magnetic fluid, and to investigate the efficiency of extraction of Fe 3+ ions by the fungus biomass of the fungus Pleurotus ostreatus . Methods . The standard method of cultivation of the fungus Pleurotus ostreatus , the method of high-grade magnetic separation and the method of biosorption of ferric ions were used. Results. The process of biosorption of ferric ions by a Pleurotus ostreatus grown on substrates with the addition of magnetic fluids of different concentrations was carried out. It is shown that the dry biosorbent based on the biomass of the Pleurotus ostreatus has a high sorption capacity with respect to Fe 3+ ions since the efficiency of their extraction for 30 minutes of sorption in the samples grown on the substrate with the addition of magnetite is more than 95%. It is proved that when using biomass of ordinary fungus grown on a magnetic fluid, complete saturation occurs 6 times faster (for 5 minutes), compared to 30 min for biosorbent based on biomass of mushroom grown without magnetic fluid. Conclusions. Addition of magnetite (concentration 0.1 and 1 mg/ml) to the substrate in the cultivation of fungi Pleurotus ostreatus significantly increases the efficiency of the sorbent. When using the fungus biomass of Pleurotus ostreatus without adding magnetite for 5 minutes, the efficiency of extraction of iron ions is 70%, for 30 min – 80%. When used to grow the magnetic fluid at a concentration of 0.1 mg/ml and 1 mg/ml for almost 5 minutes, almost complete removal of heavy metal ions occurs.

Nanoscale Heat Transfer from Magnetic Nanoparticles and Ferritin in an Alternating Magnetic Field

Recent suggestions of nanoscale heat confinement on the surface of synthetic and biogenic magnetic nanoparticles during heating by radio frequency-alternating magnetic fields have generated intense interest because of the potential utility of this phenomenon for noninvasive control of biomolecular and cellular function. However, such confinement would represent a significant departure from the classical heat transfer theory. Here, we report an experimental investigation of nanoscale heat confinement on the surface of several types of iron oxide nanoparticles commonly used in biological research, using an all-optical method devoid of the potential artifacts present in previous studies. By simultaneously measuring the fluorescence of distinct thermochromic dyes attached to the particle surface or dissolved in the surrounding fluid during radio frequency magnetic stimulation, we found no measurable difference between the nanoparticle surface temperature and that of the surrounding fluid for three distinct nanoparticle types. Furthermore, the metalloprotein ferritin produced no temperature increase on the protein surface nor in the surrounding fluid. Experiments mimicking the designs of previous studies revealed potential sources of the artifacts. These findings inform the use of magnetic nanoparticle hyperthermia in engineered cellular and molecular systems.

Transformation Cycle of Magnetosomes in Human Stem Cells: From Degradation to Biosynthesis of Magnetic Nanoparticles Anew.

The nanoparticles produced by magnetotactic bacteria, called magnetosomes, are made of a magnetite core with high levels of crystallinity surrounded by a lipid bilayer. This organized structure has been developed during the course of evolution of these organisms to adapt to their specific habitat and is assumed to resist degradation and to be able to withstand the demanding biological environment. Herein, we investigated magnetosomes' structural fate upon internalization in human stem cells using magnetic and photothermal measurements, electron microscopy, and X-ray absorption spectroscopy. All measurements first converge to the demonstration that intracellular magnetosomes can experience an important biodegradation, with up to 70% of their initial content degraded, which is associated with the progressive storage of the released iron in the ferritin protein. It correlates with an extensive magnetite to ferrihydrite phase transition. The ionic species delivered by this degradation could then be used by the cells to biosynthesize magnetic nanoparticles anew. In this case, cell magnetism first decreased with magnetosomes being dissolved, but then cells remagnetized entirely, evidencing the neo-synthesis of biogenic magnetic nanoparticles. Bacteria-made biogenic magnetosomes can thus be totally remodeled by human stem cells, into human cells-made magnetic nanoparticles.

RGD-functionalized magnetosomes are efficient tumor radioenhancers for X-rays and protons

Although chemically synthesized ferro/ferrimagnetic nanoparticles have attracted great attention in cancer theranostics, they lack radio-enhancement efficacy due to low targeting and internalization ability. Herein, we investigated the potential of RGD-tagged magnetosomes, bacterial biogenic magnetic nanoparticles naturally coated with a biological membrane and genetically engineered to express an RGD peptide, as tumor radioenhancers for conventional radiotherapy and proton therapy. Although native and RGD-magnetosomes similarly enhanced radiation-induced damage to plasmid DNA, RGD-magnetoprobes were able to boost the efficacy of radiotherapy to a much larger extent than native magnetosomes both on cancer cells and in tumors. Combined to magnetosomes@RGD, proton therapy exceeded the efficacy of X-rays at equivalent doses. Also, increased secondary emissions were measured after irradiation of magnetosomes with protons versus photons. Our results indicate the therapeutic advantage of using functionalized magnetoparticles to sensitize tumors to both X-rays and protons and strengthen the case for developing biogenic magnetoparticles for multimodal nanomedicine in cancer therapy.

MAGNETIC HYPERTHERMIA OF MICROORGANISMS WITH NATURAL FERRIMAGNETIC PROPERTIES

Мета: Зазвичай у практиці знешкодження мікроорганізмів магнітною гіпертермією не враховують наявність у останніх власних біогенних магнітних наночастинок. Мета дослідження виявити мікроорганізми, для яких врахування характеристик їх власних біогенних магнітних наночастинок може привести до помітного зростання ефективності магнітної гіпертермії.Методи: У дослідженні використано методи порівняльної геноміки, зокрема, попарне вирівнювання з використанням бази даних Genbank. Проведено вирівнювання протеомівмагнітотаксисної бактерії Magnetospirillumgryphiswaldense MSR-1 з протеомами патогенних мікроорганізмів, які були класифіковані за місцем локалізації і типом внутрішньої будови  їх біогенних магнітних наночастинок.Результати: Проаналізовано геноми 24 штамів  патогенних мікроорганізмів, які належать до таких родів: Staphylococcus, Pseudomonas, Bacillus, Shigella, Clostridioides, Streptococcus, Peptostreptococcus. Показано, що 2 із них мають кристалічні внутрішньоклітинні біогенні магнітні наночастинки, зовнішньоклітинні кристалічні – 11 штамів, внутрішньоклітинні аморфні – 8 штамів, зовнішньоклітинні аморфні – 3 штами. Також в роботі представлені розрахунки сил диполь-дипольних взаємодій між аморфними біогенними наночастинками Staphylococcusaureus та штучними магнітними наночастинками. Обговорення: Ми рекомендуємо використовувати методи порівняльної геноміки для поділу мікроорганізмів за магнітними властивостями для підбору більш ефективного способу знешкодження магнітною гіпертермією. Так 3 штами, що продукують кристалічні внутрішньоклітинні біогенні магнітні наночастинки, можна знешкодити методом магнітної гіпертермії, використовуючи у якості магнітного матеріалу їх власні наночастинки. 21 штам із зовнішньоклітинними кристалічними, внутрішньоклітинними аморфними та зовнішньоклітинними аморфними біогенними магнітними наночастинками, можна знешкодити магнітною гіпертермією, використовуючи методи штучного магнітомічення. Показано, що сил диполь-дипольних взаємодій між аморфними магнітними наночастинками та штучними магнітними наночастинками достатньо для того, щоб магнітомітити S. aureus і в подальшому знешкоджувати їх за допомогою магнітної гіпертермії. Висновки: Отже, врахування природних феримагнітних властивостей мікроорганізмів підвищить ефективність знешкодження магнітною гіпертермією.