Репозиторий Университета

© 2020 Cellulose nanocrystals (CNC), also known as nanowhiskers, have recently gained much attention due to their biodegradable nature, advantageous chemical and mechanical properties, economic value and renewability thus making them attractive for a wide range of applications. However, before these materials can be considered for potential uses, investigation of their toxicity is prudent. Although CNC exposures are associated with pulmonary inflammation and damage as well as oxidative stress responses and genotoxicity in vivo, studies evaluating cell transformation or tumorigenic potential of CNC's were not previously conducted. In this study, we aimed to assess the neoplastic-like transformation potential of two forms of CNC derived from wood (powder and gel) in human pulmonary epithelial cells (BEAS-2B) in comparison to fibrous tremolite (TF), known to induce lung cancer. Short-term exposure to CNC or TF induced intracellular ROS increase and DNA damage while long-term exposure resulted in neoplastic-like transformation demonstrated by increased cell proliferation, anchorage-independent growth, migration and invasion. The increased proliferative responses were also in-agreement with observed levels of pro-inflammatory cytokines. Based on the hierarchical clustering analysis (HCA) of the inflammatory cytokine responses, CNC powder was segregated from the control and CNC-gel samples. This suggests that CNC may have the ability to influence neoplastic-like transformation events in pulmonary epithelial cells and that such effects are dependent on the type/form of CNC. Further studies focusing on determining and understanding molecular mechanisms underlying potential CNC cell transformation events and their likelihood to induce tumorigenic effects in vivo are highly warranted.

© 2020 Cellulose nanocrystals (CNC), also known as nanowhiskers, have recently gained much attention due to their biodegradable nature, advantageous chemical and mechanical properties, economic value and renewability thus making them attractive for a wide range of applications. However, before these materials can be considered for potential uses, investigation of their toxicity is prudent. Although CNC exposures are associated with pulmonary inflammation and damage as well as oxidative stress responses and genotoxicity in vivo, studies evaluating cell transformation or tumorigenic potential of CNC's were not previously conducted. In this study, we aimed to assess the neoplastic-like transformation potential of two forms of CNC derived from wood (powder and gel) in human pulmonary epithelial cells (BEAS-2B) in comparison to fibrous tremolite (TF), known to induce lung cancer. Short-term exposure to CNC or TF induced intracellular ROS increase and DNA damage while long-term exposure resulted in neoplastic-like transformation demonstrated by increased cell proliferation, anchorage-independent growth, migration and invasion. The increased proliferative responses were also in-agreement with observed levels of pro-inflammatory cytokines. Based on the hierarchical clustering analysis (HCA) of the inflammatory cytokine responses, CNC powder was segregated from the control and CNC-gel samples. This suggests that CNC may have the ability to influence neoplastic-like transformation events in pulmonary epithelial cells and that such effects are dependent on the type/form of CNC. Further studies focusing on determining and understanding molecular mechanisms underlying potential CNC cell transformation events and their likelihood to induce tumorigenic effects in vivo are highly warranted.

© 2020 Elsevier Ltd In this paper, we perform a systematic analysis of the structural organization of bacterial cellulose (BC). We report four types of organization of the BC mass, produced by Gluconacetobacter hansenii that occur depending on cultivation conditions. Two of those, particularly, plywood type one and layers of micro-sized tubes were observed and described for the first time. In spherical BC particles (pellets), we found the layered structure that had previously been reported for planar geometry only. We suggest a model explaining why layers form in BC films and attempt to reveal the impact of different factors on the BC microscale morphology. We assume that the main factor that has direct impact on the type of structure formed is the rate of BC mass accumulation.

© 2020 Elsevier Ltd In this paper, we perform a systematic analysis of the structural organization of bacterial cellulose (BC). We report four types of organization of the BC mass, produced by Gluconacetobacter hansenii that occur depending on cultivation conditions. Two of those, particularly, plywood type one and layers of micro-sized tubes were observed and described for the first time. In spherical BC particles (pellets), we found the layered structure that had previously been reported for planar geometry only. We suggest a model explaining why layers form in BC films and attempt to reveal the impact of different factors on the BC microscale morphology. We assume that the main factor that has direct impact on the type of structure formed is the rate of BC mass accumulation.

© 2020 Elsevier Ltd In this paper, we perform a systematic analysis of the structural organization of bacterial cellulose (BC). We report four types of organization of the BC mass, produced by Gluconacetobacter hansenii that occur depending on cultivation conditions. Two of those, particularly, plywood type one and layers of micro-sized tubes were observed and described for the first time. In spherical BC particles (pellets), we found the layered structure that had previously been reported for planar geometry only. We suggest a model explaining why layers form in BC films and attempt to reveal the impact of different factors on the BC microscale morphology. We assume that the main factor that has direct impact on the type of structure formed is the rate of BC mass accumulation.

© 2020 Elsevier B.V. Telomerase activity has been demonstrated in a wide variety of most solid tumors and considered as a well-known cancer biomarker. The commonly utilized method for its detection is polymerase chain reaction (PCR)-based telomeric repeat amplification protocol (TRAP). However, the TRAP technique suffers from false-negative results caused by the failure of PCR step. Moreover, it requires advanced equipment with a tedious and time-consuming procedure. Herein, we presented a portable nitrocellulose paper-based nanobiosensing platform for ultrafast and equipment-free detection of telomerase activity based on a simple colorimetric assay that enabled naked-eye visualization of the color change in response to enzyme activity. In this platform, hybridization was initially performed between telomere complementary oligonucleotide immobilized on gold nanoparticles (GNPs) and telomerase elongated biotinylated probe. Thereafter, the assembly was attached on activated paper strip via avidin-biotin interaction. The signal amplification was carried out by enlargement of the attached GNPs on the paper strip, forming tightly compact rod-shaped submicron structures of gold representing a visual color formation. Thanks to significant sensitivity enhancement, the color change was occurred for down to 6 cells, which can be easily observed by the naked eye. Due to the desired aspects of the developed assay including PCR-free, low cost, simple, and high sensitivity, it can be used for evaluation of telomerase activity in cell extracts for future clinical applications. Furthermore, this design has the ability to be easily integrated into lab-on-chip devices for point-of-care telomerase sensing.

© 2018, Advanced Scientific Research. All rights reserved. The composition described in current article is based on derivatives of glucosamine and acrylate polymers and is intended for treatment of various infected wounds. A semi-transparent gel demonstrates complex therapeutic activity due to several active pharmaceutical ingredients (AFIs): chitosan, chymopsin, miramistin, and lidocaine hydrochloride. Mechanism of action of the developed drug is complex and includes several therapeutic effects: enzymatic biochemical wound debridement due to lysis of denaturated proteins (without healthy tissues damaging); indirect antimicrobial activity due to chymopsin that promotes lysis of microbial growth medium; direct antimicrobial effect is provided by miramistine; and the pain is reduced by lydocaine and intrinsic cooling effect of gel dosage form. Generalizing the literature data about the products used in the infected wounds treatment, the following AFIs were chosen for the development of the topical gel: complex of proteolytic agent chymopsin and chitosan, chitosan-miramistin complex, and lidocaine anesthetic. Hydroxypropyl methylcellulose, polyacrylamide, and glycerol were utilized as excipients. Proper development of vehicles for gels used in wound treatment can be justified by the necessity of soft action on the wound, required cooling effect, good release of AFIs from the matrix, and prevention of microbial growth.

© 2018 by the authors. Composite fibers and films based on cellulose and betulin were spun for the first time from solutions in N-methylmorpholine-N-oxide using the dry-wet jet method. The rheological properties of the composite solutions did not reveal any fundamental difference from those of the cellulose solutions. Introduction of betulin into the cellulose matrix (up to 10%) led to a decrease in the mechanical properties of the obtained fibers. The structure of the composite fibers was analyzed using SEM and X-ray diffraction methods. It was shown that the introduction of an additive into the cellulose matrix led to a decrease in the structural ordering of the cellulose. Comparative studies of the antibacterial activity of the composite films on Escherichia coli (E. coli) were carried out. The antifungal activity of the composite films was estimated using the strain of the O-97 Trichoderma viride Pers ex Fr (Gause Institute of New Antibiotics, Moscow, Russia).

© 2018, Peter the Great St. Petersburg Polytechnic University. Layers of different materials, including nanocomposites, containing carbon nanotubes, with the tensoresistive properties are discussed. The investigated layers are divided into two groups: without (group I) and with carbon nanotubes (group II). A group-I material that is the most suitable for fabrication of a tensoresistor is the elastomer with microchannel, filled with a conductive liquid. In group II, these are the (0.2-10)-μm-thick layers consisting of the carboxymethylcellulose matrix, filled with multiwalled carbon nanotubes (∼5 wt.%). The investigated layers can be used as alternative tensoresistors for medical applications.

© Copyright 2018 Inderscience Enterprises Ltd. This paper is concerned with the studies of a natural nanomaterial which is bacterial cellulose synthesised by Gluconacetobacter hansenii producer strain. It covers different fields of bacterial cellulose use, including medicine. The research has proved that bacterial cellulose matrices with immobilised cells have high potential as immobilisers of cells, including making probiotics of prolonged action. The matrices consisted of bacterial cellulose films were prepared by static cultivation of G. hansenii GH-1/2008 strain in the liquid medium. We have developed methods of washing out end toxins and producer cells of the films in the solutions of sodium bicarbonate, sodium dodecyl sulphate, and sodium hydroxide. The LAL-test has revealed that washing the films with sodium dodecyl sulphate is more efficient. By means of electron scanning and atomic force microscopy (AFM), we have determined that bacterial cellulose matrices have a layered structure, smooth surface, and adhesion of E. coli test strain cells. The adhesive capacity, the energy of adhesion and contact angle is higher for 50 um thick films than for 20 um thick ones. The bacterial cellulose matrices obtained by the biosynthesis of G. hansenii strain can be recommended for the immobilisation of different producer cells.