Spray-dried cyclophosphamide-loaded polyhydroxyalkanoate microparticles: design and characterization.

Background And Purpose: Cyclophosphamide (CP) is a widely used antitumor and immunosuppressive drug, but it is highly cytotoxic and has carcinogenic and teratogenic potential. To reduce adverse effects of CP therapy and the frequency of its administration, the microencapsulation of CP into biodegradable polymeric matrices can be performed. However, according to the literature, only a few polymers were found suitable to encapsulate CP and achieve its' sustained release.

Biosynthesis of Polyhydroxyalkanoates in B-10646 on Saturated Fatty Acids.

It has been established that the wild-type B-10646 strain uses saturated fatty acids (SFAs) for growth and polyhydroxyalkanoate (PHA) synthesis. It uses lauric (12:0), myristic (14:0), palmitic (16:0) and stearic (18:0) acids as carbon sources; moreover, the elongation of the C-chain negatively affects the biomass and PHA yields. When bacteria grow on C12 and C14 fatty acids, the total biomass and PHA yields are comparable up to 7.

Correction: Volova et al. Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition. 2021, , 1553.

In the original publication [...

Characteristics of Microparticles Based on Resorbable Polyhydroxyalkanoates Loaded with Antibacterial and Cytostatic Drugs.

The development of controlled drug delivery systems, in the form of microparticles, is an important area of experimental pharmacology. The success of the design and the quality of the obtained microparticles are determined by the method of manufacture and the properties of the material used as a carrier. The goal is to obtain and characterize microparticles depending on their method of preparation, the chemical composition of the polymer and the load of the drugs.

Properties of Degradable Polyhydroxyalkanoates Synthesized from New Waste Fish Oils (WFOs).

The synthesis of PHA was first investigated using WFOs obtained from smoked-sprat heads, substandard fresh sprats, and fresh mackerel heads and backbones. All the WFOs ensured the growth of the wild-type strain B-10646 and the synthesis of PHA, regardless of the degree of lipid saturation (from 0.52 to 0.

Biodegradable Polyhydroxyalkanoates with a Different Set of Valerate Monomers: Chemical Structure and Physicochemical Properties.

The properties, features of thermal behavior and crystallization of copolymers containing various types of valerate monomers were studied depending on the set and ratio of monomers. We synthesized and studied the properties of three-component copolymers containing unusual monomers 4-hydroxyvalerate (4HV) and 3-hydroxy-4-methylvalerate (3H4MV), in addition to the usual 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) monomers. The results showed that P(3HB--3HV--4HV) and P(3HB--3HV--3H4MV) terpolymers tended to increase thermal stability, especially for methylated samples, including an increase in the gap between melting point (T) and thermal degradation temperature (T), an increase in the melting point and glass transition temperature, as well as a lower degree of crystallinity (40-46%) compared with P(3HB--3HV) (58-66%).

Three-Dimensional Printing of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] Biodegradable Scaffolds: Properties, In Vitro and In Vivo Evaluation.

The results of constructing 3D scaffolds from degradable poly(3-hydrosbutyrpate-co-3-hydroxyvalerate) using FDM technology and studying the structure, mechanical properties, biocompatibility in vitro, and osteoplastic properties in vivo are presented. In the process of obtaining granules, filaments, and scaffolds from the initial polymer material, a slight change in the crystallization and glass transition temperature and a noticeable decrease in molecular weight (by 40%) were registered. During the compression test, depending on the direction of load application (parallel or perpendicular to the layers of the scaffold), the 3D scaffolds had a Young's modulus of 207.

Effect of Monomers of 3-Hydroxyhexanoate on Properties of Copolymers Poly(3-Hydroxybutyrate- 3-Hydroxyhexanoate).

The properties of poly(3-hydroxybutyrate--3-hydroxyhexanoate) P(3HB--3HHx) copolymers with different ratios of monomers synthesized by the wild-type strain B-10646 on sugars, and an industrial sample from Kaneka synthesized by the recombinant strain NSDG-ΔfadB1 on soybean oil, were studied in a comparative aspect and in relation to poly(3-hydroxybutyrate) P(3HB). The copolymer samples, regardless of the synthesis conditions or the ratio of monomers, had reduced values of crystallinity degree (50-60%) and weight average molecular weight (415-520 kDa), and increased values of polydispersity (2.8-4.

Biosynthesis and Properties of Sulfur-Containing Polyhydroxyalkanoates (PHAs) Produced by Wild-Type Strain B-10646.

The study addresses the growth of the wild-type strain B-10646 and the synthesis of sulfur-containing polyhydroxyalkanoates (PHA) by this strain on media containing fructose and three different precursors (3-mercaptopropionic acid, 3',3'-dithiodipropionic acid and 3',3'-thiodipropionic acid). By varying the concentration and number of doses of the precursors added into the bacterial culture, it was possible to find conditions that ensure the formation of 3-mercaptopropionate (3MP) monomers from the precursors and their incorporation into the C-chain of poly(3-hydroxybutyrate). A series of P(3HB--3MP) copolymer samples with different content of 3MP monomers (from 2.

Influence of PHA Substrate Surface Characteristics on the Functional State of Endothelial Cells.

The needs of modern regenerative medicine for biodegradable polymers are wide and varied. Restoration of the viability of the vascular tree is one of the most important components of the preservation of the usefulness of organs and tissues. The creation of vascular implants compatible with blood is an important task of vascular bioengineering.

Modification of Polyhydroxyalkanoates Polymer Films Surface of Various Compositions by Laser Processing.

The results of surface modification of solvent casting films made from polyhydroxyalkanoates (PHAs) of various compositions are presented: homopolymer poly-3-hydroxybutyrate P(3HB) and copolymers comprising various combinations of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate(4HB), and 3-hydroxyhexanoate (3HHx) monomers treated with a CO laser in continuous and quasi-pulsed radiation modes. The effects of PHAs film surface modification, depending on the composition and ratio of monomers according to the results of the study of SEM and AFM, contact angles of wetting with water, adhesion and growth of fibroblasts have been revealed for the laser radiation regime used. Under continuous irradiation with vector lines, melted regions in the form of grooves are formed on the surface of the films, in which most of the samples have increased values of the contact angle and a decrease in roughness.

Resorbable Nanomatrices from Microbial Polyhydroxyalkanoates: Design Strategy and Characterization.

From a series of biodegradable natural polymers of polyhydroxyalkanoates (PHAs)-poly-3-hydroxybutyrate (P(3HB) and copolymers containing, in addition to 3HB monomers, monomers of 3-hydroxyvalerate (3HV), 3-hydroxyhexanoate (3HHx), and 4-hydroxybutyrate (4HB), with different ratios of monomers poured-solvent casting films and nanomembranes with oriented and non-oriented ultrathin fibers were obtained by electrostatic molding. With the use of SEM, AFM, and measurement of contact angles and energy characteristics, the surface properties and mechanical and biological properties of the polymer products were studied depending on the method of production and the composition of PHAs. It has been shown in cultures of mouse fibroblasts of the NIH 3T3 line and diploid human embryonic cells of the M22 line that elastic films and nanomembranes composed of P(3HB-co-4HB) copolymers have high biocompatibility and provide adhesion, proliferation and preservation of the high physiological activity of cells for up to 7 days.

Biosynthesis and Properties of a P(3HB--3HV--4HV) Produced by B-10646.

Synthesis of P(3HB--3HV--4HV) copolymers by the wild-type strain B-10646 on fructose or sodium butyrate as the main C-substrate with the addition of γ-valerolactone as a precursor of 3HV and 4HV monomers was studied. Bacterial cells were cultivated in the modes that enabled production of a series of copolymers with molar fractions of 3HV (from 7.3 to 23.

Degradable Poly(3-hydroxybutyrate)-The Basis of Slow-Release Fungicide Formulations for Suppressing Potato Pathogens.

Three-component slow-release fungicide formulations with different modes of action of the active ingredients for suppressing potato pathogens were constructed for the first time. The difenoconazole, mefenoxam, prothioconazole, and azoxystrobin fungicides were embedded in the degradable polymer P(3HB)/birch wood flour blend and examined using SEM, IR spectroscopy, X-ray analysis, DTA, and DSC. Results showed that no chemical bonds were established between the components and that they were physical mixtures that had a lower degree of crystallinity compared to the initial P(3HB), which suggested different crystallization kinetics in the mixtures.

Effectiveness of slow-release fungicide formulations for suppressing potato pathogens.

Background: For the first time, the biological activity of slow-release fungicide formulations for suppressing potato pathogens deposited in a degradable poly-3-hydroxybutyrate/sawdust base has been obtained and investigated.

Results: The slow-release fungicide formulations (azoxystrobin, azoxystrobin + mefenoxam, and difenoconazole) were studied in vitro and in vivo in comparison with commercial analogues. In in vitro cultures of phytopathogens, the deposited fungicides showed an inhibitory effect comparable to commercial analogues, limiting the growth of colonies of Phytophthora infestans, Alternaria longipes, Rhizoctonia solani and Fusarium solan (2.

Cytogenotoxic activity of herbicidal and fungicidal pesticides on Triticum aestivum root meristem.

Phytotoxicity, cytotoxicity and genotoxicity of pesticides with various mechanisms of targeted activity were studied in a hydroponic culture of 2-day-old seedlings of Triticum aestivum. All studied pesticides (with the exception of metribuzin) exhibited dose-dependent phytotoxicity (inhibited the growth of the main root and reduced the yield of root biomass). All studied pesticides did not affect mitotic index in the root apex meristem but did affect the duration of some phases of mitosis.

Sugar Beet Molasses as a Potential C-Substrate for PHA Production by .

To increase the availability and expand the raw material base, the production of polyhydroxyalkanoates (PHA) by the wild strain B-10646 on hydrolysates of sugar beet molasses was studied. The hydrolysis of molasses was carried out using -fructofuranosidase, which provides a high conversion of sucrose (88.9%) to hexoses.

Bacterial Cellulose (BC) and BC Composites: Production and Properties.

The synthesis of bacterial cellulose (BC) by strain B-12068 was investigated on various C-substrates, under submerged conditions with stirring and in static surface cultures. We implemented the synthesis of BC on glycerol, glucose, beet molasses, sprat oil, and a mixture of glucose with sunflower oil. The most productive process was obtained during the production of inoculum in submerged culture and subsequent growth of large BC films (up to 0.

Production and Properties of Microbial Polyhydroxyalkanoates Synthesized from Hydrolysates of Jerusalem Artichoke Tubers and Vegetative Biomass.

One of the major challenges in PHA biotechnology is optimization of biotechnological processes of the entire synthesis, mainly by using new inexpensive carbon substrates. A promising substrate for PHA synthesis may be the sugars extracted from the Jerusalem artichoke. In the present study, hydrolysates of Jerusalem artichoke (JA) tubers and vegetative biomass were produced and used as carbon substrate for PHA synthesis.

Assessment of the efficacy of slow-release formulations of the tribenuron-methyl herbicide in field-grown spring wheat.

The efficacy of slow-release formulations of tribenuron-methyl (TBM) embedded in the matrix of degradable poly(3-hydroxybutyrate) blended with birch wood flour [polymer/wood flour/herbicide 50/30/20 wt.%] was compared with the efficacy of TBM as the active ingredient of the Mortira commercial formulation, which was applied as post-emergence spray to treat spring wheat cv. Novosibirskaya 15.

Properties of Degradable Polyhydroxyalkanoates (PHAs) Synthesized by a New Strain, IBP/SFU-1, from Various Carbon Sources.

The bacterial strain isolated from soil was identified as IBP/SFU-1 and investigated as a PHA producer. The strain was found to be able to grow and synthesize PHAs under autotrophic conditions and showed a broad organotrophic potential towards different carbon sources: sugars, glycerol, fatty acids, and plant oils. The highest cell concentrations (7-8 g/L) and PHA contents were produced from oleic acid (78%), fructose, glucose, and palm oil (over 80%).

Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition.

The study reports results of using a CO-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%).

Thermomechanical Analysis of Isora Nanofibril Incorporated Polyethylene Nanocomposites.

The research on cellulose fiber-reinforced nanocomposites has increased by an unprecedented magnitude over the past few years due to its wide application range and low production cost. However, the incompatibility between cellulose and most thermoplastics has raised significant challenges in composite fabrication. This paper addresses the behavior of plasma-modified polyethylene (PE) reinforced with cellulose nanofibers extracted from isora plants (i.

Metabolic activity of cryogenic soils in the subarctic zone of Siberia towards "green" bioplastics.

The present study investigates, for the first time, the structure of the microbial community of cryogenic soils in the subarctic region of Siberia and the ability of the soil microbial community to metabolize degradable microbial bioplastic - poly-3-hydroxybutyrate [P(3HB)]. When the soil thawed, with the soil temperature between 5-7 and 9-11 °C, the total biomass of microorganisms at a 10-20-cm depth was 226-234 mg g soil and CO production was 20-46 mg g day. The total abundance of microscopic fungi varied between (7.

The effect of the pesticide delivery method on the microbial community of field soil.

The study deals with the effects of herbicides (metribuzin, tribenuron-methyl, fenoxaprop-P-ethyl) and fungicides (tebuconazole, epoxiconazole, azoxystrobin) applied to soil as free pesticides or as slow release formulations embedded in a biodegradable composite matrix on the structure of the soil microbial community. The matrix consisted of a natural biopolymer poly-3-hydroxybutyrate [P(3HB)] and a filler-one of the natural materials (peat, clay, and wood flour). The soil microbial community was characterized, including the major eco-trophic groups of bacteria, dominant taxa of bacteria and fungi, and primary P(3HB)-degrading microorganisms, such as Pseudomonas, Bacillus, Pseudarthrobacter, Streptomyces, Penicillium, and Talaromyces.