High Molecular Chitosan Research Articles

Experimental Early Stimulation of Bone Tissue Neo-Formation for Critical Size Elimination Defects in the Maxillofacial Region.

A biomaterial is proposed for closing extensive bone defects in the maxillofacial region. The composition of the biomaterial includes high-molecular chitosan, chondroitin sulfate, hyaluronate, heparin, alginate, and inorganic nanostructured hydroxyapatite. The purpose of this study is to demonstrate morphological and histological early signs of reconstruction of a bone cavity of critical size. The studies were carried out on 84 white female rats weighing 200-250 g. The study group consisted of 84 animals in total, 40 in the experimental group and 44 in the control group. In all animals, three-walled bone defects measuring 0.5 × 0.4 × 0.5 cm3 were applied subperiosteally in the region of the angle of the lower jaw and filled in the experimental group using lyophilized gel mass of chitosan-alginate-hydroxyapatite (CH-SA-HA). In control animals, the bone cavities were filled with their own blood clots after bone trepanation and bleeding. The periods for monitoring bone regeneration were 3, 5, and 7 days and 2, 3, 4, 6, 8, and 10 weeks. The control of bone regeneration was carried out using multiple morphological and histological analyses. Results showed that the following process is an obligatory process and is accompanied by the binding and release of angiogenic implantation: the chitosan construct actively replaced early-stage defects with the formation of full-fledged new bone tissue compared to the control group. By the 7th day, morphological analysis showed that the formation of spongy bone tissue could be seen. After 2 weeks, there was a pronounced increase in bone volume (p < 0.01), and at 6 weeks after surgical intervention, the closure of the defect was 70-80%; after 8 weeks, it was 100% without violation of bone morphology with a high degree of mineralization. Thus, the use of modified chitosan after filling eliminates bone defects of critical size in the maxillofacial region, revealing early signs of bone regeneration, and serves as a promising material in reconstructive dentistry.

Ecological Sorption of Iron and Sulfate Ions onto Starch and Chitosan Biopolymer Blend

Providing safe drinking water free of heavy metal ions like iron and oxyanions like sulfate has become a worldwide issue. Starch, as one of the widely cheapest and available biomaterials, has demonstrated its capability to adsorb heavy metal ions from water in various scientific research, but in low adsorption rates. Therefore, this paper aims to prepare a biopolymer based on a starch–chitosan blend to raise the adsorption efficiency of starch. Two types of chitosan were used to modify potato starch (ps): low molecular chitosan (ch60) and high molecular chitosan (ch4000). Nano potato starch (n.ps) was prepared from potato starch and was also modified with both chitosans. The surface property, the morphology, the particle size, and the structure of the samples were analyzed. Moreover, the investigation of the samples by the zeta potential and charge density were evaluated to determine the charge of the adsorbents’ surface. Furthermore, the pseudo first order (PFO) and pseudo second order (PSO) were employed to examine the adsorption kinetic. The adsorption isotherms of Fe2+/3+ and SO42− were fitted employing Langmuir, Sips, and Dubinin-Radushkevich adsorption models. The maximum achieved sorption capacities from the FeSO4 solution for Fe2+/3+ were as follows: 115 mg/g for n.ps &amp; ch4000, 90 mg/g for ps &amp; ch4000, 80 mg/g for n.ps &amp; ch60, and 61 mg/g for ps &amp; ch60. Similarly, for SO42−, it was 192 mg/g for n.ps &amp; ch4000, 155 mg/g for n.ps &amp; ch60, 137 mg/g for ps &amp; ch4000, and 97 mg/g for ps &amp; ch60.

Influence of the complex of chitosan-ß-cyclodextrin with levofloxacin on the wounds’ microflora and the Sturgeon’s colon intestine

The authors in the article presented the results of determining the effectiveness of using the chitosan-ß-cyclodextrin complex with levofloxacin in the healing of mechanical wounds of valuable commercial fish sturgeons and their feeding. The experiment was conducted based on the “Progressive biotechnologies in aquaculture” research laboratory of the Saratov State University of Genetics, Biotechnology and Engineering. N.I. Vavilov. The microflora of incised wounds and the large intestine of sturgeon fingerlings under the influence of fluoroquinolone, represented by levofloxacin based on cyclodextrin, included in the shell of high-molecular chitosan, was studied. The studied microbiological indicators were chosen to determine that changes in the total number of microorganisms show the nature of the course of the inflammatory/pathological process, which contributes to the development of microorganisms (including opportunistic pathogens) and lactic acid bacteria in the intestine. Therefore, they are essential physiological indicators of the formation of “ intestinal immunity. It was found that the use of cyclodextrin with levofloxacin in the treatment of incised wounds in sturgeons leads to a significant decrease in the total microbial number (TMC) on their surface (by 10 thousand times compared to the group without treatment). It has been shown that using cyclodextrin with levofloxacin in feeding sturgeons reduces the total microbial number in the large intestine. This complex is characterised by good solubility and bioavailability for fish. The future study results can be used in aquaculture to treat mechanical injuries received during transportation and sorting in the rearing process in fish.

POLYELECTROLYTE COMPLEX NANOPARTICLES OF SOLUBLE LIGNIN AND CHITOSAN AS INTERFACIAL MODIFIER

A water-soluble non-stoichiometric polyelectrolyte complex (LCP) was obtained as a result of the interaction of oppositely charged kraft lignin and high molecular chitosan by mixing their dilute water solutions. The sizes of the LCP nanoparticles were characterized by a bimodal distribution at pH 6, and their values were essentially smaller than the sizes of the chitosan particles. It was found that the LCP nanoparticles were characterized by remarkably lower values of surface tension at the air-water and the water-organic liquid interface in comparison with the initial biopolymers. With decreasing pH and increasing concentration of the LCP nanoparticles in the water solution, their adsorption ability at the interfaces was enhanced. The interface tension at the water-heptane interface changed non-linearly with increasing the polyelectrolyte complex concentration that was associated with the “saturation” effect. The dependence of the ability of the LPC nanoparticles to stabilize oil-in-water emulsion on pH values of the water phase was found.

Comparative study of nanocarrier for Eupatorium perfoliatum 3C by low molecular over high molecular chitosan for efficient encapsulation and dye degradation applications

AbstractThis study focuses on encapsulating the drug with enhanced efficiency and characterizing the same environmental applications. Efficient encapsulation and conjugation of this remarkable drug with chitosan have never been attempted before. Loading into a nanocarrier extends the efficiency of the boneset from being general folk medicine to a specialized functional moiety that even works as potential nanomedicine and dye degeneration. Eupatorium perfoliatum 3C loaded in the chitosan nanocarrier was performed using an ionotropic gelation method. Physicochemical properties were analyzed using a pH meter, UV‐Vis spectrophotometer, scanning electron microscopy, and Fourier Transform Infrared (FTIR) analysis high‐performance liquid chromatography (HPLC). A dye degradation assay was done for four commercially available dyes, namely, safranin, methyl red as well as orange, and methylene blue. Irrespective of chitosan's molecular weight, methyl orange is degraded the most by E. perfoliatum 3C formulation by 31.9% at 90 min. In terms of encapsulation efficiency, lower molecular chitosan shows 96% encapsulation of the drug within its surface. Thus, manifesting itself as a potential nanocarrier for therapeutic applications in the future.

Antibacterial Activity of Silver Nanodispersions in Solutions of Different Molecular Weight Chitosans

AbstractThe results of the testing of silver nanoparticles (AgNPs) antibacterial activity obtained in aqua solutions of high molecular chitosan and oligochitosans at near‐physiological pH values are demonstrated. Aggregative stable AgNPs were synthesized in solutions of chitosans of average molecular weight of 6, 12 and 311 kDa. Nanodispersions were characterized by UV‐Vis and FTIR, SEM and TEM. AgNPs formation was confirmed by the presence of the surface plasmon resonance peak at nearly 425 nm in the extinction spectrum and TEM. The average size of approximately 40–90 nm was determined by DLS, electron microscopy and UV‐Vis. Minimal inhibitory concentrations were determined by microdilution in the Mueller‐Hinton broth method. The AgNPs dispersions exhibit a significant antibacterial effect toward both Gram‐positive and Gram‐negative bacteria strain (MIC values are of 1–8 μg/ml). The effect is little dependent on polymer molecular weight. A two‐stage Staphylococcus aureus growth suppression effect was found for the first time.

THE INFLUENCE OF CHITOSANES ON THE DYNAMICS OF THE CONTENT OF PHENOLIC COMPOUNDS IN TOMATO LEAVES

The aim of this work was to study the influence of chitosans of different molecular weight on the dynamics of the content of phenolic compounds in tomato plants of the 'Zagadka' variety. In the experiment, tomato plants treated with chitosan with a molecular weight of 50-190 kDa and 310-375 kDa were studied. Using the method of high-performance thin-layer chromatography (HPTLC), biochemical profiling of the extracts of the studied plants was performed. Differences in the primary reactions of plants to chitosans of different molecular weights were revealed. Low molecular chitosan caused a significant increase in the content of phenols and, accordingly, increased the antioxidant potential of leaf tissues. The increase in the content of phenols in response to the action of low-molecular-weight chitosan occurs due to the activation of phenylpropanoid synthesis and an increase in the total antioxidant potential, which indicates the mobilization of the plant organism against a potential pathogen. Thus, an hour after the treatment of plants with a solution of low molecular weight chitosan, the content of rutin in the leaves was 3.36 mg/g, and after 18 hours - 5.56 mg/g. The content of chlorogenic and caffeic acids in the leaves increased in 12 hours. In 18 hours, the content of chlorogenic acid was 1.64 mg/g, and caffeic acid was 0.18 mg/g. This may be due to the gradual decomposition of chlorogenic acid into its constituent components under the influence of low molecular weight chitosan, which is accompanied by the release of caffeic acid. A positive correlation was established between the pool of chlorogenic and caffeic acid (r = 0.995; p &lt; 0.06). Therefore, depending on the molecular weight, chitosan causes significant changes in the synthesis of phenylpropanoids and biochemical transformation of complex and simple esters of hydroxycinnamic acids in tomato plants. The high-molecular chitosan solution caused a decrease in the number of compounds with high antioxidant potential in tomato leaves, which indicates the activation of another plant defense system. The content of rutin in leaves treated with high-molecular-weight chitosan after 18 hours was 1.32 mg/g, which is four times less compared to the treatment of plants with low-molecular-weight chitosan. At the same time, in response to treatment with high molecular weight chitosan, the content of caffeic acid in the leaves increased significantly. The decrease in the content of phenols is associated with the isolation of tissues from a potential threat, which is aimed at its neutralization. The result of such a reaction is the oxidation of phenolic compounds, additional lignification and suberinization of cell walls. The activation of various induced immunity reactions in the plant organism already in the first hours after eating low-molecular or high-molecular chitosan indicates the existence of a system of differential recognition of complex bipolymers by plants.

Chitosan과 9-Layer 고산소차단성필름을 활용한 진공저장환경에서 한우의 품질특성 변화

The effect of chitosan on the antibacterial effect, antioxidant, color, moisture content and pH of Hanwoo stored at 10°C was investigated. The packaging film used for packaging was checked for storability by utilizing 9-Layer multi layed packaging film to maintain quality during storage of Hanwoo. All concentrations of low-viscosity chitosan not showed very strong antibacterial effect on meat spoilage bacteria at all concentrations. In this studies, rather High viscosity chitosan showed a very strong effect at 0.1% or higher. The shelf life of Hanwoo soaked in 1% of high-viscosity chitosan was extended. In terms of lipid peroxidation, cuted Hanwoo exhibited a improved lipid peroxidation inhibitory effect at all concentrations of high-viscosity chitosan. In addition, redness of Hanwoo was also stably maintained in the evaluation of color difference. In Hanwoo treated with low-molecular and high-molecular chitosan, the moisture content during the entire storage period (12 days) showed a tendency to decrease slightly as the viscosity and concentration during storage increased. As a result, it was found that the treatment was effective at 1.0% in low-viscosity and high-viscosity chitosan for the characteristics of Hanwoo.

Evaluation of shear bond strength of high molecular chitosan nanoparticle incorporated heat polymerized polymethyl methacrylate denture base resin with acrylic resin teeth: An in-vitro study

The present study is conducted to evaluate the shear bond strength of acrylic resin denture teeth to high molecular chitosan nanoparticle incorporated heat polymerized polymethylmethacrylate denture base resin. This comparative study is performed at the Department of Prosthodontics and Crown & Bridge, JSSDCH, Mysuru. 45 samples of acrylic resin blocks of size 8 × 10 × 20 mm were fabricated using mold such that the long axis of crosslinked acrylic resin maxillary central incisor teeth is aligned at 45° to the long side of the specimen to which the ridge lap surface is attached. Among these, 15 samples belong to the control group, 15 samples to the 0.5 % chitosan gel incorporated group, and the remaining 15 samples to the 1 % chitosan gel incorporated group. The test specimens were then subjected to a failure load test using the universal testing machine. The readings were tabulated and statistically analyzed using Mean, Standard deviation, Independent t-test, - way and two-way ANOVA, and Scheffes’ Post hoc test. The statistical analysis reveals that the mean bond strength of acrylic denture teeth to conventional heat cure PMMA denture base material increased from 4.6627 ± 0.54198 MPa to 7.5186 ± 0.57461 MPa and 8.9356 ± 0.63675 MPa upon addition of chitosan at 0.5 % and 1 % concentration, respectively. It can be concluded that The mean shear bond strength of acrylic denture teeth to conventional heat cure PMMA denture base material increased with the addition of chitosan at 0.5 and 1 % concentration. The best shear bond strength was observed with the addition of 1 % chitosan as per the evidence.

Comparison Study of Fabrication and Characterization of Bead Chitosan Hydrogel and Yarn Chitosan Hydrogel From High Molecular Chitosan

The research about comparison study of fabrication and characterization of bead chitosan hydrogel and yarn chitosan hydrogel from high molecular chitosan has been successfully conducted. High molecular chitosan was dissolved into 100 ml of 1, 1.5, and 2% of acetic acid and stirred until the chitosan was dissolved completely. The formed chitosan solution was then taken as much as 6 mL using a syringe and dropped slowly to form small beads into a Petri dish containing NaOH 0.3 M then string into a Petri dish containing acetone 1% and dried at ±50ºC. The bead chitosan hydrogel and yarn chitosan hydrogen results were characterized in which differences of functional groups on chitosan with beads chitosan hydrogel and yarn chitosan hydrogel that occurred in the highest spectra peaks was the band at 3433.29 cm-1, which indicated NH groups on chitosan had changed into an O-H group (3653.18 cm-1) on the bead chitosan hydrogels 1% and yarn chitosan hydrogel 1% which showed the existence of chemical interactions. The yarn chitosan hydrogel has better absorption capability compared to bead chitosan hydrogel. Due to the surface area of the chitosan yarn hydrogel being wider than the beads' chitosan hydrogel.

The Effect of Chitosan Hydrolysate on Solanum Lycopersicum Plant Growth

Chitosan is a well-known subjectof researchbecause of its beneficial properties, including its antibacterial and fungicidal activity, as well as its effect on plant physiology. One of the maindifficulties in agricultural chitosan implementation is the poor solubility of high molecular chitosan in water. Reducing themolecular weight of chitosan by acid hydrolysis increases its solubility. This research studied the effect of chitosan hydrolysate on the germination and development ofSolanum lycopersicum L. plants. Theeffects of chitosan hydrolysate on seed germination, shoot development in the first week of development and in the first month of development were evaluated. According to the results, high concentrations of chitosan hydrolysate completely inhibited seed germination. However, short-term treatment by high concentrations of chitosan hydrolysate stimulatedthe development of seedlings, leading to substantially longerroots. Regular root application of high concentrations of chitosan hydrolysate inhibited plant development.&#x0D; Keywords: chitosan hydrolysate, chitosan, plant growth regulators, plant germination

The potential of high molecular chitosan nanohydroxyapatite as an irrigant in improving fracture resistance after root canal treatment (In Vitro)

ABSTRACT Teeth after root canal treatment are at a higher risk of fracture than vital teeth. After root canaltreatment, the causes of tooth fracture are multifactorial, both iatrogenic and non iatrogenic. One of them isirrigants, although very useful for disinfection. Irrigants are known to change the chemical components andstructure of the root canal surface dentin by modifying the proportion of calcium and phosphate minerals. Thisresearch is an experimental laboratory study with a post-test-only group research design to analyze the effect ofirrigating solutions of nanohydroxyapatite, high molecular chitosan, NaOCl, and EDTA with their appropriatecombination for the test group on the fracture resistance of teeth after root canal treatment. Root canal treatment wasperformed on 24 mandibular premolars, with the group I; irrigating solution of nanohydroxyapatite, group II;irrigation of nanohydroxyapatite solution with the addition of 0.2% chitosan, group III; irrigation with 2.5% NaOClsolution and 0.2% chitosan solution, group IV; irrigation solution of 2.5% NaOCl and 17% EDTA. ANOVA testshowed a significant difference in fracture resistance (p0.05) between each group. The highest average fractureresistance was seen in group II, namely the irrigation group using a solution of nanohydroxyapatite with theaddition of 0.2% chitosan, which was 363.644 ± 10,896 N. fracture after root canal treatment.KEYWORDS: nanohydroxyapatite, irrigation solution, fracture resistance

Diffusion of calcium ions in one-third of root canals after administration of high molecular Chitosan nanohydroxyapatite medicament (In Vitro)

ABSTRACT Calcium hydroxide is currently the gold standard medicament. Still, it has the disadvantage of leavinga residue on the surface of the root canal wall. Hence, it can interfere with the setting time and adhesion of the sealermaterial to the root canal wall. This study aims to determine the ability of calcium ion diffusion in one-third of theroot canal after administration of nanohydroxyapatite medicament with a different vehicle than calcium hydroxide.This study used 24 mandibular premolars extracted, decorated, and prepared, then grouped into four treatmentgroups. Based on the paired T-test, the study results showed no significant effect of calcium ion diffusion in group B(p = 0.739) on the 7th and 14th days. The ANOVA test results showed no significant difference in calcium ion diffusion between groups A, B, and C. on the 7th day of testing (p=0.773) and the 14th day (p=0.661). In conclusion, there was no effect and difference in the diffusion of calcium ions in the apical third after administration ofmedicament nanohydroxyapatite vehicle bidisstilled water and nanohydroxyapatite vehicle nanochitosan compared tocalcium hydroxide on the 7th and 14th day KEYWORDS: diffusion, calcium hydroxide, ion calcium, nanohydroxyapatite, nano chitosan, vehicle

Simultaneous production of low molecular weight chitosan and reducing sugar via high molecular chitosan depolymerization by surface discharge plasma

Chitosan is widely used in antibacterial, hypolipidemic, and anticancer fields, and the preparation of low molecular weight chitosan with excellent solubility and hydrophilicity is beneficial for its application. In this study, simultaneous production of low molecular weight chitosan and reducing sugars via chitosan depolymerization by surface discharge plasma was developed. More than 95% of the chitosan with an initial molecular weight of 682.5 kDa was depolymerized after 60 min of treatment, with the reducing sugar yield of 23.7%. ·OH, O2·-, and 1O2 played important roles in chitosan depolymerization; they preferentially attacked the amorphous structure of chitosan, resulting in breakage of the intra- and intermolecular hydrogen bonds and β-(1,4) glycosidic bonds, thereby forming low molecular weight chitosan. More electrons and hydrogen atoms would be provided by prepared low molecular weight chitosan due to the decreased intra- and intermolecular hydrogen bonds, and a high biological activity was finally attained. Overall, discharge plasma could be used as an effective technique for chitosan depolymerization, which widens its potential applications.

Application of transglutaminase in moulded food processing from waterlogged fish raw materials

Application conditions of the ACTIVA® TG-TI transglutaminase combined with setting agents (gelatine and chitosans of various modifications) are substantiated for moulded food processing from waterlogged fish raw materials targeted by deep-water fishery, i.e. giant grenadier (Albatrossia pectoralis). It was shown that combining different setting agents ensures time reduction of gel formation with a minor change in their development and melting temperatures. Adding an enzyme preparation leads to the formation of thermostable gels with a 1.5-fold increased strength. When forming gels from the grenadier muscle tissue in the presence of setting agents of different concentrations, the quality of soluble muscle proteins reduces, most prominently with gelatine and chitosan ascorbate. Physicochemical parameters of the structured gels prepared from the muscle tissue of giant grenadier (moisture retention capacity, tensile strength, water activity) and their organoleptic profiles were measured. Based on the results, we have shown that adding 3% of gela-tine, 0.06% of high-molecular chitosan and 1% of transglutaminase may be employed for processing moulded fish products. The digestibility of the protein components in obtained samples did not depend on fermentation. The overall protein deposition was between 0.38 and 0.56% of the sample mass. The total biological value of samples ranged from 78 to 134% when studying their effect on the growth of T. pyriformis testing culture.

Оптимизация методики иммобилизации фицина с использованием глутарового альдегида

Ficin was covalently immobilized on an acid-soluble matrix of medium (200 kDa) and high molecular weight (350 kDa) chitosans. The enzyme molecules were immobilized in a protein film and copolymerized with glutaraldehyde. The optimal ratio of protein content, total activity and specific activity was observed as a result of ficin covalent immobilization on a matrix of medium-molecular chitosan with 15% glutaraldehyde and high-molecular chitosan with 10% glutaraldehyde. The obtained biocatalysts are promising for industrial applications. ficin, chitosan, glutaraldehyde, covalent immobilization. This work was financially supported by a grant from the President of the Russian Federation for state support to young Russian scientists-doctors of sciences MD-1982.2020.4. Agreement 075-15-2020-325).

High molecular chitosan-based seed shells (Tachypleus gigas) with silver nanoparticles as waste treatment of palm oil industry (pome)

The focus of this study is to Investigate, study and modification of chitosan molecules tow with nano silver particles as an adsorbent for absorbing oil industry palm oil mill effluent. Liquid waste palm oil industry (POME) from local palm oil mill is used as a sample of oily wastewater. High molecular chitosan from crab shells do crosslink raw materials has to Overcome the disadvantages as the adsorbent, the Appropriate crosslink is AgNO3 used for this study. The controlled variable is the volume of the adsorbent, contact time and pH. A batch of detailed studies on high-molecular chitosan and chitosan Also -nanoparticles and silver are conducted with respect to the adsorption capacity, isotherm. Characterization using Fourier Transform Infrared (FTIR) Spectrophotometer see changes in the functional groups of high molecular chitosan and chitosan -nanoparticle silver that has been crosslinked before and after the adsorption treatment to prove that the palm oil industry waste liquid has been absorbed by the adsorbent. The performance is assessed in terms of turbidity, total suspended solids (TSS) of chemical oxygen demand (COD), Biochemical Oxygen Demand (BOD), and Parameter metallic iron (Fe), copper (Cu) and Zinc (Zn). Using maximum adsorption capacity of the high-molecular chitosan nanoparticles of silver is calculated. This research study Will Prove the high molecular chitosan and chitosan silver -nanoparticle high molecular adsorbent after cross section as expected very potential to absorb liquid palm oil mill waste industry.

Effect of Molecular Weight and Degree of Acetylation on Adjuvantive Properties of Chitosan Derivatives

The hemostatic and immunostimulating activity and cytotoxicity were determined for a number of chitosans differing in molecular weight (from 3 to 510 kDa) and degree of acetylation (from 1 to 25 mol%) that were used as adjuvants in inactivated poliomyelitic, influenza, and live influenza vaccines. It has been shown that the hemostatic activity of chitosan increased sharply with an increase in its molecular weight. In oligochitosan with a molecular weight of <16 kDa, it was smaller by a factor of 15–100 than in chitosan with a molecular weight of 20–510 kDa. The level of increase in the immunogenicity of vaccines containing oligochitosan as adjuvants was not lower than that for the vaccine including high-molecular chitosan. However, the immunostimulatory activity of oligochitosan depended on the degree of acetylation, reaching a maximum value at 6 mol%. It was shown that all oligochitosans and chitosans with a molecular mass below ~50 kDa showed almost no cytotoxicity at a concentration of ≤2.5 mg/mL, which enable their use as adjuvants for inactivated and live vaccines at the optimal ratio of molecular weight to the degree of acetylation.

Synthesis, characterization and antioxidant activity of chitosan-chromone derivatives

In this study, a new chromone-functionalized chitosan Schiff base and its cross-linked derivative were synthesized and characterized by FT-IR, UV–vis, 13C CP/MAS solid-state NMR, TGA, XRD-powder and SEM measurements and elemental analysis data. Degrees of substitution (DS) were determined from the elemental analysis by using the C/N ratios. The in vitro antioxidant activity of high molecular chitosan and its chromone derivatives was evaluated as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). The results showed that both of the chitosan-chromone derivatives have good antioxidant potential which might be due to the phenolic group introduced after chemical modification of chitosan with a chromone derivative. Chromone-chitosan Schiff base (CSCH) had a better ability to scavenging DPPH radical (IC50, 0.88mg/mL) than that of its cross-linked derivative (CSCH-TP) obtained by using terephthalaldehyde (IC50, 1.32mg/mL).

Optical activity of films based on chitosan of various molecular masses and modifications

The effect of chemical (polysalt → polybase reaction) and physicochemical (heat and vapor processing) modifications of the films of chitosan of various molecular masses and prehistories on the optical activity of the polysaccharide is studied. For both of the chitosan chemical modifications, the following dependence that is nontrivial for high-molecular compounds is established: [α] = f(log $${\bar M_\eta }$$ ); as the degree of polymerization decreases, the modulus of [α] of the films increases. The X-ray diffraction study shows that the differences in the optical activity of the samples with different $${\bar M_\eta }$$ are caused by a restriction in the mobility of the macromolecular sections upon formation of the films of high-molecular chitosan and incompleteness of the relaxation processes of the film systems to the state with energetically favorable conformations. The comparison of humidity and optical and biological activities of the initial and dehydrated chitosan films is performed. The chitosan films in the salt modification feature moderate bactericidal activity, which decreases with an increase in $${\bar M_\eta }$$ of the polymer. The thermal processing of the salt modification reduces the antibacterial action; a conversion to the base form is accompanied by the loss of bactericidal activity.