Репозиторий Университета

© 2020 Elsevier Inc. Biopolymer composites based on two types of chitosan (chitosan succinate and low-molecular weight chitosan) with single-walled carbon nanotubes (SWCNT) were created by laser printing. SWCNT have good dispersibility in chitosan solutions and therefore, can form relatively homogeneous films that was shown in scanning electron microscopy images. For the studies film composites were formed under the action of laser radiation on aqueous dispersion media. Study of the nonlinear optical process during the interaction of laser radiation with a disperse media has shown that low-molecular chitosan has a large nonlinear absorption coefficient of 17 cm/GW, while the addition of SWCNT lead to a significant increase up to 902 cm/GW. The threshold intensity for these samples was 5.5 MW/cm2 with nanotubes. If intensity exceeds the threshold value, nonlinear effects occur, which, in turn, lead to the transformation of a liquid into a solid phase. Characterization of films by FTIR and Raman spectroscopy indicated arising molecular interactions between chitosan and SWCNT detected as a small frequency shift and a change in the shape of radial breathing mode (RBM). The results indicate the possibility using aqueous dispersion media based on chitosan and SWCNT to create three-dimensional films and scaffolds for tissue engineering by laser printing.

© 2019 WILEY-VCH Verlag GmbH  &  Co. KGaA, Weinheim Hydrophobic segments made of oligo(l,l- or d,l-lactides) or poly(l,l-lactide) are grafted onto chitosan backbone in order to use their amphiphilic behavior to prepare degradable microcarriers intended to be used for tissue engineering. Hydrophilic–lipophilic balance of these copolymers is adjusted playing on the respective length of their hydrophilic and hydrophobic moieties. Thanks to their self-emulsifying properties, these graft copolymers are processed into microspheres in the absence of hydrophilic emulsifier commonly added in the aqueous phase of the oil/water emulsion. The copolymers containing amorphous oligolactide segments of medium length are demonstrated to be the most effective ones for microparticle fabrication. The microparticles are characterized using SEM, EDX, and FTIR. The reactivity of amine group is demonstrated using fluorescein isothiocyanate staining. The resulting microspheres disclose a porous core and a shell enriched by the hydrophilic polysaccharide moieties. Stabilization of the oil/water interface during the microsphere fabrication, total yield, size distribution, and microparticle surface morphology are mainly affected by the macromolecular features of the copolymers.

© 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 SPIE. In this work, tissue-engineered structures based on a matrix of protein conjugates, chitosan and carbon nanotubes were prepared and studied. Bovine serum albumin (BSA), bovine collagen (BCrossed D sign¡) were used. Two types of single-walled carbon nanotubes (SWCNTs) were used to form a strong internal scaffold in a protein-chitosan matrix under the action of laser radiation. Tissue-engineered structures were created by means of layered deposition and laser evaporation of the initial aqueous dispersion from SWCNT, BSA, BC and chitosan succinate. As sources of laser radiation, a continuous diode laser with a wavelength of 810 nm and a pulsed fiber laser with a wavelength of 1064 nm and frequency of 80 kHz were used. Studies of tissue-engineered structures were carried out using vibrational spectroscopy methods (IR and Raman). The changes in the frequencies and intensities of the corresponding absorption bands and Raman lines of the amide group oscillations were analyzed. IR spectra of tissue-engineered structures demonstrated a high degree of binding of organic (protein, chitosan) and inorganic (SWCNT) components. The structure and defectiveness of the carbon nanotube scaffold were investigated in the Raman spectra.