scholarly journals Manufacturing technology of low-molecular-weight chitosan based on enzymatic hydrolysis

2021 ◽  
Author(s):  
E.I. Kovaleva ◽  
A.I. Albulov ◽  
M.A. Frolova ◽  
V.P. Varlamov ◽  
A.V. Grin
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Enzymatic Hydrolysis ◽  
Aqueous Solutions ◽  
High Molecular Weight ◽  
The Body ◽  
Low Molecular Weight ◽  
High Molecular Weight Polymer ◽  
Low Molecular Weight Chitosan ◽  
Chitin And Chitosan

Chitosan is natural high molecular weight polymer of D-glucosamine and N-acetyl - D - glucosamine connected by 1,4 - b - glycoside bond with a molecular mass of 1000 kDa (and above), practical use is difficult because of high viscosity of its aqueous solutions even at low concentrations, and lack of solubility at neutral pH and, consequently, low biological activity. To reduce viscosity, improve the solubility and enhance biological activity of high molecular weight chitosan subjected to depolymerization. Chitosan, like other polysaccharides, is characterized by a hydrolysis reaction, which is due to the presence of glycoside bonds in the molecule that are lable to hydrolyzing agents, for example, aqueous solutions of acids, alkalis, as well as to the effect of some hydrolases. During hydrolysis, glycoside bonds are broken and, as a result, the molecular weight of chitosan decreases. However, these processes are accompanied by the formation of significant amounts of toxic products and require very costly disposal of waste before it is discharged into the environment. Chitin and chitosan are natural biopolymers and their synthesis, modification and degradation are associated with enzymatic transformations. It is the biodegradability to the usual substances for the body that is one of the main advantages of chitosan. It is obvious that the most appropriate method is the enzymatic hydrolysis of chitosan. As enzyme preparations for the degradation of chitin and chitosan, enzyme complexes of various origins are used. These can be enzymes from crab or krill hepatopancreas complexes, as well as pancreatin from the pancreas of cattle. But more often for this purpose, enzymes complexes with chitinolytic activity of microbiological origin are used. In this study, low-molecular-weight chitosan was obtained by enzymatic hydrolysis using the extracellular chitinolytic complex of Streptomyces kurssanovii. The resulting chitosan had a medium-viscosity molecular weight of 25-40 kDa. Carrying out two stages of fractionation (stepwise acidification and separation on membranes) made it possible to obtain chitosan fractions with a narrow distribution by molecular weight.

Preparation of low-molecular-weight chitosan by enzymatic hydro-lysis for use in peliculture

2021 ◽  
pp. 31-33
Author(s):  
Элана Игоревна Ковалева ◽  
Марина Алексеевна Фролова ◽  
Алексей Иванович Албулов ◽  
Валерий Петрович Варламов ◽  
Анатолий Константинович Елисеев
Keyword(s):  
Molecular Weight ◽  
Enzymatic Hydrolysis ◽  
Environmental Factors ◽  
Low Molecular Weight ◽  
Technological Parameters ◽  
Low Molecular Weight Chitosan

Хитозан и его производные обладают множеством свойств, которые позволяют применять его в пчеловодстве. Он повышает устойчивость организма пчел к неблагоприятным факторам внешней среды и к возбудителям различных заболеваний. В результате проведенных исследований разработаны технологические параметры получения низкомолекулярного хитозана методом ферментативного гидролиза. Chitosan and its derivatives have many properties that allow them to be used in beekeeping. It increases the resistance of the bee organism to adverse environmental factors and to pathogens of various diseases. As a result of the conducted research, the technological parameters for the production of low-molecular-weight chitosan by enzymatic hydrolysis were developed.

Inhibition of Maillard reaction in production of low-molecular-weight chitosan by enzymatic hydrolysis

2020 ◽  
Vol 236 ◽  
pp. 116059
Author(s):  
Jun Zhang ◽  
Zewen Mei ◽  
Xingxi Huang ◽  
Yueyue Ding ◽  
Yunxiang Liang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Enzymatic Hydrolysis ◽  
Maillard Reaction ◽  
Low Molecular Weight ◽  
Low Molecular Weight Chitosan

The Effects of Polymer Coating of Gold Nanoparticles on Oxidative Stress and DNA Damage

2020 ◽  
Vol 39 (4) ◽  
pp. 328-340
Author(s):  
Gamze Tilbe Sen ◽  
Gizem Ozkemahli ◽  
Reza Shahbazi ◽  
Pınar Erkekoglu ◽  
Kezban Ulubayram ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Weight ◽  
Dna Damage ◽  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
High Molecular Weight ◽  
Hepg2 Cells ◽  
The Body ◽  
Low Molecular Weight ◽  
Antioxidant Parameters

Gold nanoparticles (AuNPs) have been widely used in many biological and biomedical applications. In this regard, their surface modification is of paramount importance in order to increase their cellular uptake, delivery capability, and optimize their distribution inside the body. The aim of this study was to examine the effects of AuNPs on cytotoxicity, oxidant/antioxidant parameters, and DNA damage in HepG2 cells and investigate the potential toxic effects of different surface modifications such as polyethylene glycol (PEG) and polyethyleneimine (PEI; molecular weights of 2,000 (low molecular weight [LMW]) and 25,000 (high molecular weight [HMW]). The study groups were determined as AuNPs, PEG-coated AuNPs (AuNPs/PEG), low-molecular weight polyethyleneimine-coated gold nanoparticles (AuNPs/PEI LMW), and high-molecular weight polyethyleneimine-coated gold nanoparticles (AuNPs/PEI HMW). After incubating HepG2 cells with different concentrations of nanoparticles for 24 hours, half maximal inhibitory concentrations (the concentration that kills 50% of the cells) were determined as 166.77, 257.73, and 198.44 µg/mL for AuNPs, AuNPs/PEG, and AuNPs/PEI LMW groups, respectively. Later, inhibitory concentration 30 (IC30, the concentration that kills 30% of the cells) doses were calculated, and further experiments were performed on cells that were exposed to IC30 doses. Although intracellular reactive oxygen species levels significantly increased in all nanoparticles, AuNPs as well as AuNPs/PEG did not cause any changes in oxidant/antioxidant parameters. However, AuNPs/PEI HMW particularly induced oxidative stress as evidence of alterations in lipid peroxidation and protein oxidation. These results suggest that at IC30 doses, AuNPs do not affect oxidative stress and DNA damage significantly. Polyethylene glycol coating does not have an impact on toxicity, however PEI coating (particularly HMW) can induce oxidative stress.

Experimental Study on Flow-Front Fingering Instabilities in Injection Molding of Polymer Solutions and Melts

2004 ◽  
Author(s):  
Kalonji K. Kabanemi ◽  
Jean-Franc¸ois He´tu ◽  
Samira H. Sammoun
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polymer Solutions ◽  
Low Molecular Weight ◽  
Flow Front ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Polymer Molecules ◽  
Molecular Weights ◽  
Solvent Molecules

An experimental investigation of the flow behavior of dilute, semi-dilute and concentrated polymer solutions has been carried out to gain a better understanding of the underlying mechanisms leading to the occurrence of instabilities at the advancing flow front during the filling of a mold cavity. Experiments were performed using various mass concentrations of low and high molecular weight polyacrylamide polymers in corn syrup and water. This paper reports a new type of elastic fingering instabilities at the advancing flow front that has been observed only in semi-dilute polymer solutions of high molecular weight polymers. These flow front elastic instabilities seem to arise as a result of a mixture of widely separated high molecular weight polymer molecules and low molecular weight solvent molecules, which gives rise to a largely non-uniform polydisperse solution, with respect to all the kinds of molecules in the resulting mixture (solvent molecules and polymer molecules). The occurrence of these instabilities appears to be independent of the injection flow rate and the cavity thickness. Moreover, these instabilities do not manifest themselves in dilute or concentrated regimes, where respectively, polymer molecules and solvent molecules are minor perturbation of the resulting solution. In those regimes, smooth flow fronts are confirmed from our experiments. Based on these findings, the experimental investigations have been extended to polymer melts. Different mixtures of polycarbonate melts of widely separated molecular weights (low and high molecular weights) were first prepared. The effect of the large polydispersity of the resulting mixtures on the flow front behavior was subsequently studied. The same instabilities at the flow front were observed only in the experiments where a very small amount of high molecular weight polycarbonate polymer has been mixed to a low molecular weight polycarbonate melt (oligomers).

scholarly journals Chitosan-based biomaterials used in critical-size bone defects: radiographic study in rat's calvaria

2012 ◽  
Vol 41 (5) ◽  
pp. 312-317 ◽  
Author(s):  
Rubens Spin-Neto ◽  
Felipe Leite Coletti ◽  
Rubens Moreno de Freitas ◽  
Chaíne Pavone ◽  
Sérgio Paulo Campana-Filho ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Bone Density ◽  
High Molecular Weight ◽  
Critical Size ◽  
Bone Defects ◽  
Control Group ◽  
Low Molecular Weight ◽  
Chitosan Hydrochloride ◽  
Low Molecular Weight Chitosan ◽  
High Molecular Weight Chitosan

OBJECTIVE: This study evaluated, using digital radiographic images, the action of chitosan and chitosan hydrochloride biomaterials, with both low and high molecular weight, used in the correction of critical-size bone defects (CSBD's) in rat's calvaria. MATERIAL AND METHOD: CSBD's with 8 mm in diameter were surgically created in the calvaria of 50 Holtzman rats and these were filled with a blood clot (Control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride and high molecular weight chitosan hydrochloride, for a total of 10 animals, which were divided into two experimental periods (15 and 60 days), for each biomaterial. The radiographic evaluation was made using two digital radiographs of the animal's skull: one taken right after the bone defect was created and the other at the moment of the sacrifice, providing the initial and the final radiographic bone density in the area of the defect, which were compared. RESULT: Analysis of radiographic bone density indicated that the increase in the radiographic bone density of the CSBD's treated with the proposed biomaterials, in either molecular weight, in both observed periods, where similar to those found in control group. CONCLUSION: Tested chitosan-based biomaterials were not able to enhance the radiographic density in the CSBD's made in rat's calvaria.

scholarly journals THE NON-VIRUS PROTEINS ASSOCIATED WITH TOBACCO MOSAIC VIRUS

1955 ◽  
Vol 38 (4) ◽  
pp. 459-473 ◽  
Author(s):  
Barry Commoner ◽  
Mas Yamada
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Infected Plant ◽  
Infected Leaf ◽  
Low Molecular Weight ◽  
Tobacco Plants ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Derivatives Of ◽  
Virus Proteins

1. Exhaustive fractionation of leaves from tobacco plants systemically infected with TMV has led to the isolation of two non-virus proteins, B3 and B6, and the detection of a third, A4, which do not occur in comparable uninfected plants. 2. Components B3 and B6 have been found consistently in a series of ten extracts from plants grown over an 18 month period in all seasons of the year. It is concluded that these components are as characteristic of the infected plant as TMV itself. 3. As they occur in the initial extracts, the non-virus proteins are of low molecular weight (S20 ca. 3). On treatment, each component tends to form a high molecular weight polymer with an electrophoretic mobility considerably greater than that of the starting material. The high molecular weight derivatives of A4, B3, and B6 have been designated A8, B8, and B7 respectively. There is no evidence that these high molecular weight components occur as such in the infected leaf. 4. The non-virus proteins are free of nucleic acid and are not infectious. They cross-react immunochemically with TMV. 5. Compared with TMV content, the amounts of the non-virus proteins found in infected leaf are relatively small, falling in the range of 10 to 150 micrograms per gm. of tissue.

scholarly journals APPROACHES TO THE SELECTION OF EXCIPIENTS FOR DENTAL GEL WITH CETYLPYRIDINIUM CHLORIDE

2021 ◽  
Vol 9 (1) ◽  
pp. 54-63
Author(s):  
E. Yu. Zagorulko ◽  
A. S. Karavaeva
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Cetylpyridinium Chloride ◽  
Poloxamer 407 ◽  
Low Molecular Weight ◽  
Complex Evaluation ◽  
Low Molecular Weight Chitosan ◽  
Penetration Ability ◽  
Osmotic Activity ◽  
High Molecular Weight Chitosan

The aim of the study was to determine the excipients influence on the characteristics of gels with cetylpyridinium chloride and to select the dental gel formulation gelation agents promising for the development of dental gel compositions. Hereby, the properties of the active pharmaceutical ingredient, characteristics of the specific gelation agents, as well as their influence on stability, biopharmaceutical and application properties of gels, were taken into account. Materials and methods. In this study, polymers with various gelation mechanisms were considered. Their compatibility with cetylpyridinium chloride as well as storing kinetic and colloid kinds of stability, pH of aqueous solutions, spreadability and textural properties, a penetration ability by the agar diffusion method, an osmotic activity and rheological properties of the gels, were examined. For a complex evaluation of gel compositions study results, a desirability function was used.Results. Stable homogenous dental gels with cetylpyridinium chloride can be obtained by using 25% poloxamer 407 and 5.0% high molecular weight chitosan as the basis.The addition of poloxamer 188 to high molecular weight chitosan gels can produce stable systems with improved textural characteristics as well as increase their osmotic activity. Agar and low molecular weight chitosan addition significantly decrease, whereas poloxamer188 and various molecular weight polyethyleneglycol increase the osmotic activity of 25 % poloxamer 407 gels which are also characterized by a high penetration ability.Conclusion. A complex evaluation of biopharmaceutical, physicochemical and application properties of the gels made it possible to establish that combinations of poloxamer 407 with polyvinylpyrrolidone, agar, and low molecular weight chitosan, can be recommended as a base for a dental gel with cetylpyridinium chloride.

scholarly journals Biological Activity of Native and Low Molecular Weight Chitosan obtained by Steam Explosion Process

2018 ◽  
Vol 21 (9) ◽  
pp. 441-447 ◽  
Author(s):  
Dina Sugiyanti ◽  
Purnama Darmadji ◽  
Umar Santoso ◽  
Yudi Pranoto ◽  
Chairil Anwar ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Steam Explosion ◽  
Low Molecular Weight ◽  
Explosion Process ◽  
Low Molecular Weight Chitosan

Perbedaan Pengaruh Aplikasi Gel Kombinasi Kitosan Berat Molekul Tinggi dan Rendah dengan Ekstrak Lidah Buaya (Aloe vera) Terhadap Kepadatan Kolagen pada Proses Penyembuhan Ulkus Traumatikus

DENTA ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 60
Author(s):  
Sularsih Sularsih ◽  
Michelle Suhartono ◽  
Nafi’ah Nafi’ah
Keyword(s):  
Molecular Weight ◽  
Wound Healing ◽  
High Molecular Weight ◽  
Aloe Vera ◽  
Collagen Fibers ◽  
Control Group ◽  
Low Molecular Weight ◽  
Group I ◽  
Significant Difference ◽  
Low Molecular Weight Chitosan

<p><strong><em>Background:</em></strong><em> Traumatic ulcer is one of the most common oral wounds. Chitosan has mucoadhesive characteristic while Aloe vera containing lignin which is able to penetrate the skin. It is expected that the combined gel of chitosan and Aloe vera will function as wound healing accelerator in traumatic ulcer. Molecular weight is one of the characteristics of chitosan quality. <strong>Purpose:</strong> the aim of this experiment was to know the density of collagen fibers in wound healing of traumatic ulcer using the combined gel of chitosan with different molecular weight and Aloe vera. <strong>Materials and method: </strong>30 Male Rattus Norvegicus were divided into 3 groups. Group I was control group (without chitosan and Aloe vera), group II was given low molecular weight chitosan and Aloe vera, group III was given high molecular weight chitosan and Aloe vera. The groups were given traumatic ulcer making with 4 mm diameter and 2 mm depth. Rats were sacrificed by decapitation on day 3 and 7 then they were examined histopatologically to see the density of collagen fibers. <strong>Result:</strong> Statistical analysis with Kruskall Wallis and Mann-Whitney U test showed that there were significant difference p&lt;0,05 between high and low molecular weight chitosan with Aloe vera group on day 3 and 7. <strong>Conclusion:</strong> Chitosan with high molecular weight and Aloe vera were more effective in wound healing of traumatic ulcer b</em><em>ecause they increase</em><em> the density of collagen fibers.</em><em></em></p><p><strong><em> </em></strong></p><p><strong><em>Keywords:</em></strong><em>  Combined gel of chitosan and Aloe vera, density of collagen fibers, wound healing.</em><em></em></p><p><strong><em> </em></strong></p><strong><em>Korespondensi:</em></strong><em> Sularsih, Bagian Ilmu Biomaterial Kedokteran Gigi, Fakultas Kedokteran Gigi, Universitas Hang Tuah, Arif Rahman Hakim 150, Telepon 031-5912191.</em>

Sign in / Sign up

Export Citation Format

Share Document