Low Molecular Weight Chitosan Research Articles

Low molecular weight chitosan hydrolyzate inhibits the growth of some phytopathogenic Ascomycota fungi

The work studied the effect of low molecular weight chitosan hydrolyzate on the growth and development of phytopathogens Botrytis cinerea, Fusarium solani, Alternaria solani. Chitosan hydrolyzate, when added to potato-glucose agar, inhibits the growth of mycelium in vitro of Botrytis cinerea, Fusarium solani, Alternaria solani. Treatment with chitosan hydrolyzate suppresses the development of fusarium on tomato leaves and the development of gray rot on fruits. Further studies of chitosan hydrolyzate effect mechanisms on plants can expand the scope of its application.

Searching for synergistic effects of low-molecular weight chitosan derivatives, chitosan and copper nanoparticles for wound healing ointment

A high demand for modern wound healing drugs is associated with an increasing amount of injuries, chronic and diabetic ulcers, and wound infection resistance to antibiotics. The strategy for improving antibacterial capacity along with stimulation of wound reparation seems fruitful. Chitosan and copper have multifunctional properties, possessing both regenerative and antimicrobial action. The use of modified copper nanoparticles (NPs) of optimal size and phase content in combination with low molecular weight chitosan derivatives or chitosan NPs in the hydrophilic polymer composition with cellulose opens new horizons for wound management. The best synergistic composition for wound healing was a combination of 0.002% Cu1O x NPs and 0.05% N-sulfosuccinoyl-N-carboxymethyl chitosan. Such hydrogels increase the rate of wound closure (by 37%–39% as compared to gels containing individual components and by 65% in comparison with control), to provide effective angiogenesis, re-epithelisation, collagen deposition in the wound, antibacterial activity and cell biocompatibility. The high regenerative effectiveness of ointments with copper NPs at the initial stage of wound healing seems to be a result of activation of the signal rout of the regeneration process by copper, an increase of the NO level in the wound tissue was evidenced by EPR studies. This work proposes a new approach in the development of polyfunctional ointments with wound healing and antibacterial properties.

Incorporation of Low Molecular Weight Chitosan in a Low-Fat Beef Burger: Assessment of Technological Quality and Oxidative Stability.

In the present work, incorporating low molecular weight chitosan (LMWCH) (0, 0.5, 1, and 2%) as a fat replacer into low-fat beef burgers and technological, textural, and oxidative stability were investigated. The weight loss and shrinkage of samples decreased with the increase of LMWCH concentration. In contrast, the water-holding capacity and color of burgers were enhanced by the addition of LMWCH. The instrumental TPA results indicated an increase in the LMWCH levels, significantly increasing the hardness, springiness, and gumminess but decreasing the cohesiveness of low-fat beef burgers. The TBARS and peroxide values and free fatty acid content in the burgers supplemented with LMWCH increase slower than the control sample during refrigerated storage.

Effects of the silver nanodots on the photocatalytic activity of mixed‐phase TiO2

AbstractWe present the synthesis and photocatalytic properties of mixed‐phase TiO2 nanoparticles decorated with silver nanodots obtained by environmental‐friendly wet chemical method using low molecular weight chitosan as the silver reducing agent. Structural analysis of synthesized Ag nanoparticles revealed that they crystallized in a rare hexagonal modification. High‐resolution transmission electron microscopy study shows that <3‐nm hexagonal‐Ag nanoparticles are implanted on the surface of <20‐nm anatase grains. Compared to Ag‐free TiO2 powders, implantation with Ag results in important increase in visible light absorption. The photocatalytic activity of the samples was measured by monitoring decolorization of concentrated textile dye solution (50 mg L−1 of Reactive Orange 16) under simulated solar irradiation of 280 W m−2. The optimum photocatalytic properties are achieved with 5 wt% of silver. Based on the collected results, the operating mechanism of the degradation process is suggested, and the effects of the silver addition are explained.

Synthesis and Properties of Chitosan Nanoparticles CrossLinked with Tripolyphosphate

Chitosan nanoparticles (ChNPs) have been extensively examined for various biomedical applications due to their advantages include large surface area, biodegradability, and biocompatibility. The purpose of this research was to synthesize ChNPs using a simple ionic gelation technique by the interaction of low molecular weight chitosan (LMWC) and sodium tripolyphosphate (TPP) as a cross-linking agent. ChNPs, TPP, and LMWC were analysed by X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectra that indicated the formation of ChNPs, attributing to the rearrangement of the nanoparticles after adding the TPP cross-linker into the LMWC solution. XRD analysis exhibited that ChNPs were amorphous, due to the effect of TPP cross-linker. Dynamic light scattering showed the nano-dimension of ChNPs with a hydrodynamic size of 68.50 nm. Thus, the obtained results indicated that the properties of chitosan were improved through converting it into nanoparticles using TPP initiated ionic gelation procedure.

Clinical and Radiographic Evaluation of Chitosan Particles in Treatment of Intrabony Periodontal Defects: A Clinical Trial.

Objectives: Intrabony defects are among the most important signs of progression of periodontal disease. Complete tissue regeneration is the ideal goal of periodontal treatment, and regenerative methods aim to achieve this goal. New studies have reported the positive efficacy of chitosan to enhance the recovery of bony defects. This study aimed to clinically and radiographically assess the efficacy of chitosan particles for treatment of intrabony periodontal defects. Materials and Methods: In this clinical trial, 18 intrabony three-wall periodontal defects were randomly divided into three groups (n=6). The control group only received conventional flap surgery with a sulcular incision. In the second group, low molecular weight (100,000-300,000g/mol) chitosan was used in the three-wall intrabony defects during surgery while high molecular weight chitosan particles (600,000-800,000 g/mol) were used in the third group. The probing pocket depth (PPD), clinical attachment level (CAL) and radiographic defect depth (RDD) were measured at baseline and at 6 and 12 months later. Repeated measures ANOVA, and McNemar’s test were used for statistical analysis. Results: In both the control (P<0.001) and coarse chitosan (P=0.035) groups, a significant difference was noted in PPD before and after surgery. CAL was not significantly different among the three groups (P>0.05). No significant difference was noted on radiographs between the groups regarding the regenerated bone density. Conclusion: Chitosan showed no positive efficacy for treatment of three-wall periodontal bone defects.

Dry powder formulation for pulmonary infections: Ciprofloxacin loaded in chitosan sub-micron particles generated by electrospray

Electrospray was used as a one-step technique to generate inhalable ciprofloxacin-loaded chitosan sub-micron particles with potential use in the treatment of pulmonary infections. The effect of operating parameters was studied and the preparation method optimized. The final sizes of ciprofloxacin-loaded particles were 386.1 ± 248.5 nm and 501.1 ± 276.3 nm for high and low molecular weight chitosan, respectively. The high surface charge of the particles formed, around +45 mV, enhances their mucoadhesive properties. The particles were biocompatible with alveolar cell line (A549), and showed a high antimicrobial activity against two of the most common respiratory pathogens Staphylococcus aureus and Pseudomonas aeruginosa.

Preparation of low molecular chitosan by microwave-induced plasma desorption/ionization technology

Compared with high molecular weight chitosan (HMWC), low molecular weight chitosan (LMWC) has better solubility and biological activity. However, there is no quick and environmentally friendly to prepare low molecular chitosan. In this study, microwave induced plasma desorption/ionization (MIPDI) was used for the first time to prepare LMWC through the degradation processes of HMWC. The results showed that MIPDI has the most abundant ∙OH content at the gas-liquid interface, and the active particles represented by ∙OH can degrade chitosan with a molecular weight of 540 KDa into soluble chitosan (≤ 10 KDa), and the yield of soluble chitosan can reach 61% in 60 min. Moreover, a series of characterization results showed that the chain structure and crystal structure gradually degraded as the treatment time increased while the chemical structure of chitosan did not change significantly. Antibacterial experiments also indicated that the antimicrobial property of LMWC obtained by MIPDI degradation was improved. In short, this method has proven to be a new, fast and green processing method for the preparation of low molecular chitosan.

Production of Low Molecular Weight Chitosan and Chitooligosaccharides (COS): A Review.

Chitosan is a biopolymer with high added value, and its properties are related to its molecular weight. Thus, high molecular weight values provide low solubility of chitosan, presenting limitations in its use. Based on this, several studies have developed different hydrolysis methods to reduce the molecular weight of chitosan. Acid hydrolysis is still the most used method to obtain low molecular weight chitosan and chitooligosaccharides. However, the use of acids can generate environmental impacts. When different methods are combined, gamma radiation and microwave power intensity are the variables that most influence acid hydrolysis. Otherwise, in oxidative hydrolysis with hydrogen peroxide, a long time is the limiting factor. Thus, it was observed that the most efficient method is the association between the different hydrolysis methods mentioned. However, this alternative can increase the cost of the process. Enzymatic hydrolysis is the most studied method due to its environmental advantages and high specificity. However, hydrolysis time and process cost are factors that still limit industrial application. In addition, the enzymatic method has a limited association with other hydrolysis methods due to the sensitivity of the enzymes. Therefore, this article seeks to extensively review the variables that influence the main methods of hydrolysis: acid concentration, radiation intensity, potency, time, temperature, pH, and enzyme/substrate ratio, observing their influence on molecular weight, yield, and characteristic of the product.

Chitosan/PVA Based Membranes Processed by Gamma Radiation as Scaffolding Materials for Skin Regeneration.

Some of the current strategies for the development of scaffolding materials capable of inducing tissue regeneration have been based on the use of polymeric biomaterials. Chitosan, in particular, due to its recognized biological activity has been used in a number of biomedical applications. Aiming the development of chitosan-based membranes with improved cell adhesion and growth properties to be used as skin scaffolds allowing functional tissue replacement, different formulations with chitosan of different molecular weight, poly (vinyl alcohol) and gelatin, were evaluated. To meet the goal of getting ready-to-use scaffolds assuring membranes’ required properties and sterilization, preparation methodology included a lyophilization procedure followed by a final gamma irradiation step. Two radiation dose values were tested. Samples were characterized by TGA, FTIR, and SEM techniques. Their hydrophilic properties, in vitro stability, and biocompatibility were also evaluated. Results show that all membranes present a sponge-type inner structure. Chitosan of low molecular weight and the introduction of gelatin are more favorable to cellular growth leading to an improvement on cells’ morphology and cytoskeletal organization, giving a good perspective to the use of these membranes as potential skin scaffolds.

Low-molecular weight chitosan enhances antibacterial effect of antibiotics and permeabilizes cytoplasmic membrane of Staphylococcus epidermidis biofilm cells.

This study evaluated the effect of low-molecular weight chitosan on Staphylococcus epidermidis, a common colonizer of joint implants and other prosthetic devices. We have also attempted to elucidate its mechanism of action. Chitosan was found to be effective against both the planktonic and biofilm cells (MIC80 35-40mg/L; MBIC80 40-150mg/L), in contrast to the antibiotics erythromycin and tetracycline with no antibiofilm activity (MBIC80 not found). In combination, chitosan had an additive effect with antibiotics on suspension growth of S. epidermidis (FICi 0.7-1.0), and the combinatory action caused a complete inhibition of biofilm metabolic activity in some cases. In addition, chitosan caused rapid cellular damage and enhanced antihaemolytic activity of tetracycline in combination towards S. epidermidis biofilm cells. Chitosan efficiently inhibited S. epidermidis growth acting via cell membrane damage, yet the extent of antimicrobial and antibiofilm activities was quite strain-specific. It was proved to be a very efficient antimicrobial agent worth further examination as a potent candidate in pharmaceutical research. Apart from antimicrobial activity, it also acted as antivirulence enhancing agent which is a very promising strategy for alternative infectious diseases treatment.

Development of Chitosan-Based Surfaces to Prevent Single- and Dual-Species Biofilms of Staphylococcus aureus and Pseudomonas aeruginosa.

Implantable medical devices (IMDs) are susceptible to microbial adhesion and biofilm formation, which lead to several clinical complications, including the occurrence of implant-associated infections. Polylactic acid (PLA) and its composites are currently used for the construction of IMDs. In addition, chitosan (CS) is a natural polymer that has been widely used in the medical field due to its antimicrobial and antibiofilm properties, which can be dependent on molecular weight (Mw). The present study aims to evaluate the performance of CS-based surfaces of different Mw to inhibit bacterial biofilm formation. For this purpose, CS-based surfaces were produced by dip-coating and the presence of CS and its derivatives onto PLA films, as well surface homogeneity were confirmed by contact angle measurements, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The antimicrobial activity of the functionalized surfaces was evaluated against single- and dual-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. Chitosan-based surfaces were able to inhibit the development of single- and dual-species biofilms by reducing the number of total, viable, culturable, and viable but nonculturable cells up to 79%, 90%, 81%, and 96%, respectively, being their activity dependent on chitosan Mw. The effect of CS-based surfaces on the inhibition of biofilm formation was corroborated by biofilm structure analysis using confocal laser scanning microscopy (CLSM), which revealed a decrease in the biovolume and thickness of the biofilm formed on CS-based surfaces compared to PLA. Overall, these results support the potential of low Mw CS for coating polymeric devices such as IMDs where the two bacteria tested are common colonizers and reduce their biofilm formation.

Synthesis of silicon quantum dots using chitosan as a novel reductor agent

In the present paper we report a novel synthesis method of silicon quantum dots (SiQDs) using 3-Aminopropyltriethoxysilane (APTES) as silicon precursor and low molecular weight chitosan (CS) as reducing agent. The obtained SiQDs have a hydrodynamic diameter of 2.3 nm, water dispersible, presents blue emission band at 434.5 nm (2.85 eV) with a Commission Internationale de l’Eclairage 1931 (CIE1931) chromaticity coordinates (x = 0.1665, y = 0.1222), the experimental absorbance of the SiQDS was measured and the band gap (Eg) was estimated through PerkinElmer’s method, the obtained value was 3.1 eV and a positive ζ-potential of + 35 mV, resulting in photonics, microelectronics, and biotechnological potential applications.

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.

Morphological study of the particle-to-fiber transition threshold during electrohydrodynamic processing of chitosan solution

In this work, solutions of low molecular weight chitosan with the concentration of 4 and 5 wt.% were subjected to electrohydrodynamic forming at the feed rate of 0.1 and 0.2 ml/h. Using a statistical analysis of the electron scanning microscopy data, it was shown that at the concentration of 4 wt.%, spherical particles of two types are formed: most of the particles are with the average diameter about of 260 nm, and particles with a larger diameter of about 480 nm. A transition through the particle-to-fiber threshold was observed with an increase in the concentration of the solution to 5 wt.%. This led to the formation of both spherical particles with a monomodal distribution and average diameter of 207 nm and elongated particles of a fiber-like shape with diameter of 157 nm and length of 1401 nm. At the same time, an increase in the solution feed rate resulted in a strong decrease in the average diameter of spherical particles to 150 nm and an elongation of fiber-like objects by 1.5 times. The particle-to-fiber threshold can be observed when the dynamic viscosity of the solution changes in the range of about 10–14 cP.

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

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.

Design of bioreactor based on immobilized laccase on silica-chitosan support for phenol removal in continuous mode

A silica-chitosan support was employed for laccase immobilization. The hybrid support was obtained using calcium ion as linking agent that coordinates silanol and hydroxyl groups of chitosan. The insoluble biocatalyst was then packed in a column and used in a flow system for phenol removal. The immobilized enzyme reactor (IMER) showed a good storage stability (70 % of activity in 70 days) and good reusability (90−50 % of catalytic activity at the 4th reuse in function of chitosan type). The best performance for the phenol removal was obtained with a low molecular weight chitosan from crab shells at pH 5 and with a flow rate of 0.7 mL/min. The apparent Michaelis–Menten (Vmaxapp, Kmapp) and the inherent (Vmaxinh, Kminh) constants were also determined to evaluate the influence of the phenol structure on the performance of the system. The enzymatic oxidation of a phenol mixture (4-methylcatechol, catechol, caffeic acid, syringic acid, vanillic acid, p-coumaric acid, and tyrosol) was followed for 21 h in a continuous mode by HPLC. The phenol mixture removal of 90 % was also confirmed by Folin‐Ciocalteu assay.

Mucoadhesive Low Molecular Chitosan Complexes to Protect rHuKGF from Proteolysis: In-vitro Characterization and FHs 74 Int Cell Proliferation Studies.

Recombinant Keratinocyte Growth Factor (rHuKGF) is a therapeutic protein used widely in oral mucositis after chemotherapy in various cancers, stimulating lung morphogenesis and gastrointestinal tract cell proliferation. In this research study, chitosan-rHuKGF polymeric complex was implemented to improve the stability of rHuKGF and used as rejuvenation therapy for the treatment of oral mucositis in cancer patients. Complexation of rHuKGF with mucoadhesive low molecular weight chitosan to protect rHuKGF from proteolysis and investigate the effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells. The interaction between chitosan and rHuKGF was studied by molecular docking. Malvern ZetaSizer Nano Zs and Fourier-Transform Infrared spectroscopy (FTIR) tests were carried out to characterize the chitosan-rHuKGF complex. In addition, SDS-PAGE was performed to investigate the interaction between chitosan-rHuKGF complex and pepsin. The effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells was studied by MTT assay. Chitosan-rHuKGF complex was formed through the hydrogen bonding proven by the docking studies. A stable chitosan-rHuKGF complex was formed at pH 4.5 and was protected from proteolysis and assessed by SDS PAGE. According to the MTT assay results, chitosan-rHuKGF complex increased the cell proliferation rate of FHs 74 Int cells. The developed complex improved the stability and the biological function of rHuKGF.

Properties of Low Molecular Weight Chitosan Obtained by Catalytic Degradation Using Lanthanum(III)/Halloysite Nanotube Catalysts

Properties of Low Molecular Weight Chitosan Obtained by Catalytic Degradation Using Lanthanum(III)/Halloysite Nanotube Catalysts

Antifungal action of chitosan in combination with fungicides in vitro and chitosan conjugate with gallic acid on tomatoes against Botrytis cinerea.

In the present work, a positive effect was obtained by using low molecular weight chitosan compounds in combination with synthetic fungicides. Antifungal activity against Botrytis cinerea, determined by the radial growth method, was more than 75%, with a 25 × 10- 10 g/L concentration of fludioxonil or difenoconazole in compounds. Metabolic activity of B. cinerea fungus was about 15% when using a chitosan compound containing fludioxonil at a concentration of 25 × 10- 7 g/L. The combined action of chitosan with difenoconazole at a fungicide concentration of 25 × 10- 4 g/L is 2-3 times more effective than the action of each component separately. Results of studies for artificially inoculated B. cinerea tomato fruit when treated with low molecular chitosan and chitosan conjugate with gallic acid reduced the frequency of rotting fruit by 50 and 83%, respectively. Chitosan-gallic acid conjugate were obtained from chitosans with Mw of 28 kDa (Ch28GA) was proved to be effective as a preventive treatment for 3 days and can potentially be used as a biofungicide against B. cinerea on tomatoes in the post-harvest period.