Molecular Weight Chitosan Research Articles

Simple fabrication of a photocatalyst hybridized porous chitosan-based antifouling active filter under visible light

To induce the antifouling activity of a chitosan filter of mask type under visible light such as daylight or xenon-lamp, Cr-doped TiO2 was synthesized and developed into Cr-doped TiO2 hybridized porous chitosan structures. We examined various properties such as morphology, crystallization intensity, mechanical strength, component analysis, water contact angle, and degradation efficiency of methylene blue as a measure of photocatalytic activity under xenon-lamp. We ascertained that it was optimal to combine 3 % Cr-doped TiO2, 1 % chitosan (molecular weight <1000 kDa), and an ultrasonic dispersing method to achieve good mechanical strength and optimal porous structure. Anatase Cr-doped TiO2 was successfully obtained after sintering at 300 °C for 5 h. With the exception of 6 % Cr-doped TiO2, the porosity of these hybridized porous chitosan-based filters increased with an increase in Cr-doped TiO2 concentration. Furthermore, these filters showed a methylene blue degradation efficiency of 86 %. These results indicate that Cr-doped TiO2 hybridized porous chitosan-based filters can be widely used as smart filters for self-cleaning and antifouling applications.

DNA/chitosan electrostatic complex

Up to now, chitosan and DNA have been investigated for gene delivery due to chitosan advantages. It is recognized that chitosan is a biocompatible and biodegradable non-viral vector that does not produce immunological reactions, contrary to viral vectors. Chitosan has also been used and studied for its ability to protect DNA against nuclease degradation and to transfect DNA into several kinds of cells. In this work, high molecular weight DNA is compacted with chitosan. DNA-chitosan complex stoichiometry, net charge, dimensions, conformation and thermal stability are determined and discussed. The influence of external salt and chitosan molecular weight on the stoichiometry is also discussed. The isoelectric point of the complexes was found to be directly related to the protonation degree of chitosan. It is clearly demonstrated that the net charge of DNA-chitosan complex can be expressed in terms of the ratio [NH3+]/[P−], showing that the electrostatic interactions between DNA and chitosan are the main phenomena taking place in the solution. Compaction of DNA long chain complexed with low molar mass chitosan gives nanoparticles with an average radius around 150nm. Stable nanoparticles are obtained for a partial neutralization of phosphate ionic sites (i.e.: [NH3+]/[P−] fraction between 0.35 and 0.80).

Production and Properties of Different Molecular Weights of Chitosan from Marine Shrimp Shells

Production and Properties of Different Molecular Weights of Chitosan from Marine Shrimp Shells

Mannosylation Allows for Synergic (CD44/C‐Type Lectin) Uptake of Hyaluronic Acid Nanoparticles in Dendritic Cells, but Only upon Correct Ligand Presentation

The selective targeting of dendritic cells (DCs) can lead to more efficacious vaccines. Here, materials have been designed for a synergic DC targeting: interacting with CD44 through the use of hyaluronic acid (HA), and with mannose-binding lectins (typical DC pattern recognition receptors) through HA mannosylation. Negatively charged, HA-displaying nanoparticles are produced via polyelectrolyte complexation of (mannosylated) HA and high- or low- molecular-weight chitosan (CS, 36 and 656 kDa). Using CS36, HA is better exposed and the particles have a higher affinity for HA receptors; this means a higher number of receptors clustered around each particle and, due to the rather limited CD44 availability, an overall lower uptake per cell. Employing Langerhans-like XS106 cells, all particles show negligible toxicity or inflammatory activation. The cellular uptake kinetics are qualitatively similar to other leukocytic models and thus considered to be CD44-dominated; the uptake increases with increasing HA mannosylation and with the use of adjuvants (LPS, mannan) for CS36/HA but not for CS656//HA particles; this indicates that the interactions with mannose-binding receptors requires a correct ligand presentation, and only in that case can they be enhanced by appropriate adjuvants. In summary, mannose-binding receptors can be used to enhance the internalization of HA-based carriers, although this positive synergy depends on the mode of ligand presentation.

Morphology-controlled fabrication of Ag3PO4/chitosan nanocomposites with enhanced visible-light photocatalytic performance using different molecular weight chitosan

A series of Ag3PO4 and chitosan (CS) nanocomposites (Ag3PO4/CS) were prepared through in situ growth of Ag3PO4 with different molecular weight chitosan as adsorbent and soft-template. The structure and properties of as-prepared Ag3PO4/CS nanocomposites were characterized by XRD, FT-IR, FESEM, TEM, XPS, BET and UV–vis/DRS. The visible-light photocatalytic decolorization behavior of Ag3PO4/CS nanocomposites was investigated using methyl orange as a model pollutant. It was found that the morphology and photocatalytic decolorization activity of the nanocomposites significantly depended on the molecular weight of chitosan. The decolorization of methyl orange was ascribed to the synergistic effect of photocatalysis and adsorption. When Ag3PO4/CS nanocomposites were prepared in the presence of high molecular weight chitosan, Ag3PO4 particles with cubic or rhombic dodecahedron shape and about 200 to 550nm in diameter were wrapped in chitosan. Meanwhile, when Ag3PO4/CS nanocomposites were fabricated using low molecular weight chitosan as soft-template, 150–400nm flower-like spheres were obtained which were aggregated by a large number of nanoscale Ag3PO4 crystalline grains and connected by chitosan matrix. The special morphology of Ag3PO4/CS nanocomposites greatly increased the active surface area and the photocatalytic performance. The results in this study suggested that semiconductor photocatalysts with novel morphology and enhanced photocatalytic ability could be fabricated by using different molecular weight chitosan as soft-template.

Effect of chitosan molecular weight on the formation of chitosan–pullulanase soluble complexes and their application in the immobilization of pullulanase onto Fe3O4–κ-carrageenan nanoparticles

The interactions between pullulanase and chitosans of different molecular weights (Mw) were comprehensively studied, and their applications in pullulanase immobilization onto Fe3O4–κ-carrageenan nanoparticles upon chitosan–pullulanase complexation were also evaluated. Chitosan (CS) complexation with pullulanase was found to be dependent on pH and chitosan Mw. The critical pH of structure-forming events during complexation shifted significantly (p<0.05) to a lower pH with a low Mw chitosan (50kDa) compared to other chitosan types. Binding constants for the chitosan–pullulanase interaction increased in the following order: CS-500<CS-400<CS-50<CS-200. The binding induced alterations in the protein secondary structure, which may affect the enzymatic properties of immobilized pullulanase. Pullulanase immobilized upon CS-50 complexation exhibited the most desirable enzymatic properties. These results indicated that the complexation behavior was mainly dependent on chitosan Mw. This study presents a technique for the production of immobilized pullulanase upon complexation that exhibits potential for applications in continuous syrup production.

Preparation of chitosan nanoparticles by TPP ionic gelation combined with spray drying, and the antibacterial activity of chitosan nanoparticles and a chitosan nanoparticle–amoxicillin complex

Chitosan nanoparticles were prepared from chitosan with various molecular weights by tripolyphosphate (TPP) ionic gelation combined with a spray drying method. The morphologies and characteristics of chitosan nanoparticles were determined by TEM, FE-SEM and from their mean sizes and zeta potentials. The effect of chitosan molecular weight (130, 276, 760 and 1200 cPs) and size of spray dryer nozzle (4.0, 5.5 and 7.0 µm) on mean size, size distribution and zeta potential values of chitosan nanoparticles was investigated. The results showed that the mean size of chitosan nanoparticles was in the range of 166–1230 nm and the zeta potential value ranged from 34.9 to 59 mV, depending on the molecular weight of chitosan and size of the spray dryer nozzles. The lower the molecular weight of chitosan, the smaller the size of the chitosan nanoparticles and the higher the zeta potential. A test for the antibacterial activity of chitosan nanoparticles (only) and a chitosan nanoparticle–amoxicillin complex against Streptococcus pneumoniae was also conducted. The results indicated that a smaller chitosan nanoparticle and higher zeta potential showed higher antibacterial activity. The chitosan nanoparticle–amoxicillin complex resulted in improved antibacterial activity as compared to amoxicillin and chitosan nanopaticles alone. Using a chitosan nanoparticle–amoxicillin complex could reduce by three times the dosage of amoxicillin while still completely inhibiting S. pneumoniae.

Chitosan-Based Conventional and Pickering Emulsions with Long-Term Stability

Chitosan-based conventional and Pickering oil-in-water (O/W) emulsions with very fine droplet size (volume average diameter, dv, as low as 1.7 μm) and long-term stability (up to 5 months) were ultrasonically generated at different pH values without the addition of any surfactant or cross-linking agent. The ultrasonication treatment was found to break and disperse chitosan agglomerates effectively (particularly at pH ≥ 4.5) and also reduce the chitosan molecular weight, benefiting its emulsification properties. The emulsion stability and emulsion type could be controlled by chitosan solution pH. Increasing pH from 3.5 to 5.5 led to the formation of conventional emulsions with decreasing droplet size (dv from 14 to 2.1 μm) and increasing emulsion stability (from a few days to 2 months). These results can be explained by the increase of dynamic interfacial pressure, which results from the conformation transition of chitosan molecules from an extended state to a more flexible structure as pH increases. At pH = 6.5 (the acid dissociation constant (pKa) of chitosan), the chitosan molecules self-assembled into well-dispersed nanoparticles (dv = 82.1 nm) with the assistance of ultrasonication, which resulted in a Pickering emulsion with the smallest droplet size (dv = 1.7 μm) and highest long-term stability (up to 5 months) because of the presence of chitosan solid nanoparticles at the oil/water interface. The key originality of this study is the elucidation of the role of pH in the formation of conventional and Pickering chitosan-based O/W emulsions with the assistance of ultrasonication. Our results suggest that chitosan possesses great potential to be used as an effective pH-controlled emulsifier and stabilizer without the need of other additives.

Active Molecular Chitosan (AMC-S1): Preparation and characterization of Antibacterial Activity

The aim of the present study is to prepare the chitosan hydrolysates and characterize their potential antibacterial activity. High molecular weight chitosan (CTSN-H) and medium molecular weight chitosan (MMWC, 2~10-kDa) were further degraded efficiently by using chitosanase from Bacillus subtilis JH-1122. Molecular weight (MW) of the final product was determined by MALDI-TOF MS, showed several peaks ranging from 0.8 to 2.5-kDa. Based on antibacterial activity of the hydrolysates, final products were named as active molecular chitosan (AMC-S1). AMC-S1 was evaluated as IC50 to 12.5 μg/mL of the concentration toward Candida albicans. Our present study demonstrates that AMC-S1 derived from the digestion of CTSN-H and MMWC can be selected as a potent factor affecting on antimicrobial activity against C. albicans for the industry and pharmaceutical applications.

Comparison of antimicrobial activities of newly obtained low molecular weight scorpion chitosan and medium molecular weight commercial chitosan

In this study the antimicrobial activity of low molecular weight (3.22kDa) chitosan, obtained for the first time from a species belonging to the Scorpiones, was screened against nine pathogenic microorganisms (seven bacteria and two yeasts) and compared with that of medium molecular weight commercial chitosan (MMWCC). It was observed that the antimicrobial activity of the low molecular weight scorpion chitosan (LMWSC) was specific to bacterial species in general rather than gram-negative or gram-positive bacterial groups. It was also determined that LMWSC had a stronger inhibitory effect than the MMWCC, particularly on the bacterium Listeria monocytogenes and the yeast Candida albicans, which are important pathogens for public health. In addition, it was recorded that the MMWCC had a greater inhibitory effect on Bacillus subtilis than LMWSC. According to the results obtained by the disc diffusion method, the antibacterial activity of both LMWSC and MMWCC against B.subtilis and Salmonella enteritidis was higher than the widely used antibiotic Gentamicin (CN, 10μg/disc).

Effect of different molecular weight chitosans on the mitigation of acrylamide formation and the functional properties of the resultant Maillard reaction products

Mitigation of acrylamide formation and the functional properties of Maillard reaction products (MRPs) were investigated in a food model system. The system was composed of elements of mixtures and their combination including fructose, asparagine and different molecular weight chitosans. All solutions were heated, and then analyzed for acrylamide content, MRPs absorbance, pH, color, antioxidant capacity, antibacterial activity and kinematic viscosity. The fructose, asparagine and chitosan mixture had more MRPs compared to other mixtures. 1,1-Diphenyl-2-pricrylhydrazy (DPPH) radical scavenging activities, ferrous ion chelating abilities and reducing power results showed that all solutions containing a combination of two or three reactants had antioxidant capacities. Acrylamide content has a positive correlation with absorbance values at OD294 and OD420 but a negative correlation with the CIB L∗ value of a solution (p<0.01). Experimental results evidenced that low molecular weight (50–190kDa) chitosan can be used to mitigate the formation of acrylamide.

Electrospinning chitosan/poly(ethylene oxide) solutions with essential oils: Correlating solution rheology to nanofiber formation

Electrospinning hydrophilic nanofiber mats that deliver hydrophobic agents would enable the development of new therapeutic wound dressings. However, the correlation between precursor solution properties and nanofiber morphology for polymer solutions electrospun with or without hydrophobic oils has not yet been demonstrated. Here, cinnamaldehyde (CIN) and hydrocinnamic alcohol (H-CIN) were electrospun in chitosan (CS)/poly(ethylene oxide) (PEO) nanofiber mats as a function of CS molecular weight and degree of acetylation (DA). Viscosity stress sweeps determined how the oils affected solution viscosity and chain entanglement (Ce) concentration. Experimentally, the maximum polymer:oil mass ratio electrospun was 1:3 and 1:6 for CS/PEO:CIN and:H-CIN, respectively; a higher chitosan DA increased the incorporation of H-CIN only. The correlations determined for electrospinning plant-derived oils could potentially be applied to other hydrophobic molecules, thus broadening the delivery of therapeutics from electrospun nanofiber mats.

Preparation and characterization of alginate-hyaluronic acid-chitosan based composite gel beads

The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid (HA) and Chitosan (CS) were successfully admixed with Ca2+/alginate (SA) gel system to produce SA/HA/CS gel beads by dual crosslinking: the ionic gelation and the polyelectrolyte complexation. The preparation procedure was that the weight ratio of SA (2%, m/v) to HA (2%, m/v) was kept at 2:1, then the mixture was dripped into the Ca2+ solution for ion-crosslinking, and finally polyelectrolyte crosslinked with 2% low molecular weight CS (LMW-CS) for 1.5 hours. The optimal formulation was achieved by adjusting the concentration and the weight ratio of SA, HA and LMW-CS. Due to the incorporation of HA and LMWCS, the swelling ratio of the beads at pH 7.4 was increased up to 120, and the time for the maximum swelling degree was prolonged to 7.5 h. The swelling behavior was obviously improved compared to the pure SA/Ca2+ system. The preliminary results clearly suggest that the SA/HA/CS gel beads may be a potential candidate for biomedical delivery vehicles.

Effect of different molecular weight of chitosans on performance and lipid metabolism in chicken

The effect of different molecular weight (MW) chitosans on lipid metabolism, body fat deposition, growth performance and mechanism of action of chitosans in broilers was investigated. A total of 192, 50-day-old local feather-frizzled female broilers with similar initial body weight (583±4g) were randomly divided into four groups with eight replicates of six broilers each and fed a corn–soybean meal based diet containing 0 (control), 2 (LMWC), 5 (MMWC) and 50 (HMWC) kDa MW chitosan for 42 days. Treatments did not affect the growth performance. The LMWC had no influence on fecal lipids, apparent fat metabolisability and serum concentrations of total cholesterol (TC) and triglyceride (TG), and decreased (P<0.05) the fat accumulation in both liver and muscle and abdominal fat yield. The MMWC and HMWC feeding increased fecal lipid excretion, decreased the fat accumulation in both liver and muscle and abdominal fat yield and also the serum concentrations of TC and TG (P<0.05). Both LMWC and MMWC reduced liver fatty acid synthase (FAS) activity (P<0.01), and increased liver lipoprotein lipase (LPL) and hepatic lipase activities (P<0.05). However, the HMWC feeding did not affect activities of tissue lipases except for a reduction in liver FAS activity. All three forms of chitosans improved the antioxidant status as seen by increased serum superoxide dismutase activity and decreased malondialdehyde content (P<0.05). The liver FAS mRNA did not differ among the treatment groups. There was a trend (P=0.077) for liver LPL mRNA to decrease as the chitosan MW increased. In conclusion, the three chitosans regardless of MW inhibited body fat deposition in broilers. The lipid-lowering effect of 50kDa chitosan is probably mediated by reduced dietary fat absorption. The 2kDa chitosan was useful in inducing fat catabolism, and the 5kDa chitosan appeared to act via both these mechanisms.

The Effect of β-Glycerophosphate Crosslinking on Chitosan Cytotoxicity and Properties of Hydrogels for Vaginal Application

Mucoadhesive gelling systems based on chitosan and chitosan/β-glycerophosphate (β-GP) were developed in order to increase clotrimazole residence time in the vaginal cavity. Ex vivo mucoadhesiveness using porcine vaginal mucosa followed with mechanical, viscoelastic, and swelling properties of prepared hydrogels were evaluated. Drug-free, sterile, unmodified, and β-GP crosslinked chitosan were investigated for the in vitro cytotoxicity in CRL 2616 human vaginal mucosa cells using MTT assay, fluorescent microscopy, and flow cytometry analysis. Chitosan/β-GP hydrogels exhibited pseudoplastic and thixotropic properties. Ionic interaction between β-GP and chitosan improved mechanical properties of hydrogels in terms of hardness, cohesiveness, and compressibility. The hydrogels’ ability to interact with porcine vaginal mucosa (measured as force of detachment and work of adhesion) was comparable to those obtained with reference mucoadhesive gel Replens™. Surprisingly, greater mucoadhesive properties were noticed for chitosan/β-GP hydrogels. The cytotoxic effect of unmodified and β-GP crosslinked chitosan was hardly affected by chitosan molecular weight, exhibited mainly through inducing apoptosis, and was found to be significantly lower in the presence of chitosan/β-GP. Furthermore, the higher amount of β-GP was used to crosslink chitosan, the lower cytotoxic effect was observed.

Ruthenium Recovery from Acetic Acid Waste Solution by Using PEI-Coated Biomass-Chitosan Composite Fiber

Polyethylenimine (PEI)-coated biomass-chitosan composite fiber (PBCF) was fabricated to recover Ru from acetic acid waste solution. The present work aimed to understand the effects of molecular weight of chitosan and drying method on stability and sorption performance of the PBCF. For this, the PBCF was prepared by extruding the mixed solutions of chitosan and Corynebacteriumglutamicum to form the composite fibers which were modified with ionic polymer, PEI. The degree of swelling of PBCFs prepared by hot-air, natural, and freeze drying methods were 1.25, 1.34, and 1.07 %, respectively, indicating that the freeze-drying method was the best. Batch biosorption studies showed that the maximum Ru uptake could be achieved with PBCF prepared with medium molecular weight chitosan, and could reach 34.1 mg/g, which was 7.9 times higher than that of the commercial ion exchange resin, LEWATIT® MonoPlus M 500 (4.3 mg/g). Therefore, PBCF can be considered as an alternative sorbent to synthetic resin for recovery of Ru form industrial acetic acid waste solution.

N,N,N-trimethylchitosan modified with well defined multifunctional polymer modules used as pDNA delivery vector

A novel non-viral gene carrier based on N,N,N-trimethylchitosan (TMC) has been fabricated. First, well-defined copolymer P(PEGMA-co-DMAEMA) was synthesized through reversible addition fragmentation chain transfer (RAFT) polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and N,N-(2-dimethylamino)ethyl methacrylamide (DMAEMA). Then allyl group grafting N,N,N-trimethylchitosan (Allyl-TMC) was synthesized via the reaction between allyl bromide and hydroxyl of TMC. Finally, P(PEGMA-co-DMAEMA) and folate were ordinally grafted onto Allyl-TMC to obtain TMC-g-P(PEGMA-co-DMAEMA)-FA. In comparison with pristine chitosan, TMC-g-P(PEGMA-co-DMAEMA)-FA has achieved both better water solubility and stronger pDNA packaging ability, which can contribute to improving gene transfection. Gene delivery efficiency of a series of TMC based functional polymers with different chitosan molecular weights has been tested. The results show that 20k-TMC-g-P(PEGMA-co-DMAEMA)-FA/pDNA complex at the weight ratio of 20 achieve the highest transfection efficiency in 293 T cells. This work presents a new strategy to modify chitosan efficiently as gene carrier material.

Eco-friendly innovation for nejayote coagulation–flocculation process using chitosan: Evaluation through zeta potential measurements

The main objective of the present paper is to discuss the convenience of using chitosan as a non-hazardous substance to improve the coagulation–flocculation (CF) efficiencies in nejayote (wastewater treatment containing high levels of total organic carbon, TOC=9836mg/L). For first time, two different molecular weight of chitosan in the wastewater treatment of the tortilla industry, were used as study models. The conditions here reported showed that both chitosans can be effectively used as adsorbent at pH 5.5 (mixing at 800rpm for 1min followed by a slow mixing at 200rpm for 5min) and at dosage of chitosan less than 3g/L for colloidal nejayote (without settleable solids). Both chitosan showed the highest performance under these conditions with more than 80% efficiency in turbidity removal, thus accomplishing the Mexican environmental regulation for free urban sewage discharge (NOM-002-SEMARNAT-1996). The zeta potential (ζ) of the nejayote supernatant before and after the CF treatment was used as a guiding parameter to evaluate each procedure. In addition, author suggest that the width of the flocculation window, for both chitosans in nejayote treatment, is attributed to their physical properties as molecular weight, deacetylation degree, dynamic viscosity and chemical properties as hydrogen bond, hydrophobicity and van der Waals interactions, as well as electrostatic forces that traditionally explain CF of colloids.

The effects of direct addition of low and medium molecular weight chitosan on the formation of heterocyclic aromatic amines in beef chop

The effects of direct addition of low and medium molecular weight chitosan at different levels (0.25, 0.50, 0.75 and 1%) to beef chops on the formation of heterocyclic aromatic amines (HCAs) were investigated. Chops were cooked at three different temperatures (150, 200 and 250 °C). The use of chitosan had very significant effects on water content, pH and cooking loss values of the samples. Cooking temperature had very significant effects on water content and cooking loss, while it had significant effect on pH value. On the other hand, molecular weight of chitosan had very significant effects on water content and cooking loss. While IQ and MeAαC were not detected, varying amounts of IQx (up to 0.45 ng/g), MeIQx (up to 0.09 ng/g), MeIQ (up to 0.07 ng/g), 7,8-DiMeIQx (up to 0.15 ng/g), 4,8-DiMeIQx (up to 0.05 ng/g), PhIP (up to 2.94 ng/g) and AαC (up to 0.68 ng/g) were detected. While the total HCA content ranged between non-detectable level and 4.21 ng/g, chitosan addition decreased (14.3–100%) the total HCA content.

Chitosan polyplex nanoparticle vector for miR-145 expression in MCF-7: Optimization by design of experiment

miR-145, a tumor suppressor micro RNA (miRNA), is down regulated in cancer and can be introduced as a therapeutic agent in various cancers including breast cancer. In this study, miR-145 plasmid was transfected to MCF-7 cells using chitosan polyplex nanoparticles. The vector was prepared according to an optimized fabricating method determined by response surface analysis and D-optimal design. Effects of chitosan molecular weight (Mw) and polymer amine to DNA phosphate ratio (N/P) as the variables were investigated on size, zeta potential, stability, and transfection efficiency of the polyplex nanoparticles. The results indicated that there is an interaction between effects of Mw and N/P ratio on the size of nanoparticles. Gel retardation assay demonstrated that the stability of the complexes in serum and preparation medium during storage time depends on the formulation variables. Statistical analysis affirmed that in spite of particle size, the variables of N/P ratio, time of incubation, and zeta potential affect the gene transfection. In conclusion, by selecting the perfect formulation prepared through an optimized method, it is possible to achieve a high transfection efficacy for miR-145 as an anticancer biological macromolecule.