Methyl Glycol Chitosan Research Articles

Optimization of Interfacial Properties Improved the Stability and Activity of the Catalase Enzyme Immobilized on Plastic Nanobeads.

The immobilization of catalase (CAT), a crucial oxidoreductase enzyme involved in quenching reactive oxygen species, on colloids and nanoparticles presents a promising strategy to improve dispersion and storage stability while maintaining its activity. Here, the immobilization of CAT onto polymeric nanoparticles (positively (AL) or negatively (SL) charged) was implemented directly (AL) or via surface functionalization (SL) with water-soluble chitosan derivatives (glycol chitosan (GC) and methyl glycol chitosan (MGC)). The interfacial properties were optimized to obtain highly stable AL-CAT, SL-GC-CAT, and SL-MGC-CAT dispersions, and confocal microscopy confirmed the presence of CAT in the composites. Assessment of hydrogen peroxide decomposition ability revealed that applying chitosan derivatives in the immobilization process not only enhanced colloidal stability but also augmented the activity and reusability of CAT. In particular, the use of MGC has led to significant advances, indicating its potential for industrial and biomedical applications. Overall, the findings highlight the advantages of using chitosan derivatives in CAT immobilization processes to maintain the stability and activity of the enzyme as well as provide important data for the development of processable enzyme-based nanoparticle systems to combat reactive oxygen species.

Comparative Study of Diethylaminoethyl-Chitosan and Methylglycol-Chitosan as Potential Non-Viral Vectors for Gene Therapy.

In this paper, we compared the transfection efficiency and cytotoxicity of methylglycol-chitosan (MG-CS) and diethylaminoethyl-chitosan (DEAE-CSI and DEAE-CSII with degrees of substitution of 1.2 and 0.57, respectively) to that of Lipofectamine (used as a reference transfection vector). MG-CS contains quaternary amines to improve DNA binding, whereas the DEAE-CS exhibits pH buffering capability that would ostensibly enhance transfection efficiency by promoting endosomal escape. Gel retardation assays showed that both DEAE-CS and MG-CS bound to DNA at a polysaccharide:DNA mass ratio of 2:1. In Calu-3 cells, the DNA transfection activity was significantly better with MG-CS than with DEAE-CS, and the efficiency improved with increasing polysaccharide:DNA ratios. By contrast, the efficiency of DEAE-CSI and DEAE-CSII was independent of the polysaccharide:DNA ratio. Conversely, in the transfection-recalcitrant JAWSII cells, both Lipofectamine and MG-CS showed significantly lower DNA transfection activity than in Calu-3 cells, whereas the efficiency of DEAE-CSI and DEAE-CSII was similar in both cell lines. The toxicity of DEAE-CS increased with increasing concentrations of the polymer and its degree of substitution, whereas MG-CS demonstrated negligible cytotoxicity, even at the highest concentration studied. Overall, MG-CS proved to be a more efficient and less toxic transfection agent when compared to DEAE-CS.

PEG modified liposomes containing CRX-601 adjuvant in combination with methylglycol chitosan enhance the murine sublingual immune response to influenza vaccination

The mucosa is the primary point of entry for pathogens making it an important vaccination site to produce a protective mucosal immune response. While the sublingual (SL) mucosa presents several barriers to vaccine penetration, its unique anatomy and physiology makes it one of the best options for mucosal vaccination. Efficient and directed delivery of adjuvants and antigens to appropriate immune mediators in the SL tissue will aid in development of effective SL vaccines against infectious diseases. Herein we demonstrate a robust immune response against influenza antigens co-delivered sublingually with engineered liposomes carrying the synthetic Toll-like receptor-4 agonist, CRX-601. Liposome modification with PEG copolymers (Pluronics), phospholipid-PEG conjugates and chitosan were evaluated for their ability to generate an immune response in a SL murine influenza vaccine model. Phospholipid-PEG conjugates were more effective than Pluronic copolymers in generating stable, surface neutral liposomes. SL vaccination with surface modified liposomes carrying CRX-601 adjuvant generated significant improvements in flu-specific responses compared with unmodified liposomes. Furthermore, the coating of modified liposomes with methylglycol chitosan produced the most effective flu-specific immune response. These results demonstrate efficient SL vaccine delivery utilizing a combination of a muco-adhesive and surface neutral liposomes to achieve a robust mucosal and systemic immune response.

Methylglycol chitosan and a synthetic TLR4 agonist enhance immune responses to influenza vaccine administered sublingually

Influenza is a vaccine-preventable contagious respiratory illness caused by influenza (flu) viruses which can lead to hospitalization and sometimes even death. Current flu vaccines delivered intramuscularly (IM) or intradermally (ID) are less effective at eliciting protective mucosal immune responses and vaccines delivered intranasally (IN) possess potential safety concerns. Sublingual (SL) vaccination is a promising alternative route for vaccine delivery which has been indicated as safe and effective at inducing protective immune responses in both systemic and mucosal compartments. We evaluated the efficacy of methylglycol chitosan (MGC) and a synthetic toll-like receptor 4 agonist (CRX-601), alone or in combination, for improving systemic and mucosal immune responses to a monovalent detergent-split flu virus vaccine delivered SL. SL vaccination of mice with split-flu vaccine formulated with either MGC or CRX-601 resulted in specific serum IgG and mucosal IgA titers that were significantly greater than titers from non-adjuvanted vaccination and equivalent to or greater than titers in mice vaccinated IM. Our results demonstrate that SL vaccination utilizing MGC or CRX-601 as adjuvants is a viable alternative route of vaccination for flu which can elicit systemic immune responses equivalent to or greater than IM vaccination with the added benefit of stimulating a robust specific mucosal immune response.

Genotoxicity and cytotoxicity of 2-hydroxyethyl methacrylate

Resin-based methacrylate materials are widely used in restorative dentistry. They are viscous substances that are converted into solid material via polymerization. This process, however, may be incomplete, leading to the release of monomers into the oral cavity and the pulp, which can be reached through the dentin micro-channels. This opens the opportunity for the monomers to reach the bloodstream. Monomers can reach concentrations in the millimolar range, high enough to cause cellular damage, so it is justified to study their potential toxic effects. In the present work we investigated the cytotoxicity and genotoxicity of 2-hydroxyethyl methacrylate (HEMA) in human peripheral blood lymphocytes and A549 lung-tumour cells. HEMA at concentrations up to 10 mM neither affected the viability of the cells nor interacted with isolated plasmid DNA during a 1 h exposure. However, HEMA induced concentration-dependent DNA damage in lymphocytes, as assessed by alkaline and pH 12.1 versions of the comet assay. HEMA did not cause double-strand breaks, as assessed by the neutral version of the comet assay and pulsed-field gel electrophoresis. The use of DNA repair enzymes, spin traps and vitamin C produced results suggesting that HEMA induced oxidative modifications to DNA bases. DNA damage caused by HEMA at 10 mM was removed within 120 min. HEMA induced apoptosis in a concentration-dependent manner and caused cell-cycle delay at the G0/G1-checkpoint. Methylglycol chitosan displayed a protective effect against the DNA-damaging action of HEMA. The results obtained in this study suggest that HEMA induces adverse biological effects, mainly via reactive oxygen species, which can lead to DNA damage, apoptosis and cell-cycle delay. Chitosan and its derivatives can be considered as additional components of dental restoration to decrease the harmful potency of HEMA.

Fabrication of nanoaggregates of poly(ethylene oxide)- b-polymethacrylate by complex formation with chitosan or methylglycolchitosan

Nanoaggregate formation of poly(ethylene oxide)- b-polymethacrylate (PEO-b PMA) is induced by chitosan (Ch) or methylglycolchitosan (MGC). The nanoaggregates are basically obtained by electrical charge neutralization of the anionic PMA block of the PEO-b-PMA polymer with cationic Ch or MGC, which results in insolubilization of the PMA block to form the core of the aggregates. Formation of the nanoaggregates was confirmed by dynamic light scattering, fluorescence spectroscopy, atomic force microscopy and zeta-potential measurements. The properties of the nanoaggregates depend upon the concentration of the polymer as well as the concentration of Ch or MGC. The significance of these aggregates is their ability to incorporate ionic species, leading them to potential applications as drug carriers and nanoreactors.

New insights into the fundamental nature of lignocellulosic fiber surface charge

The surface and total charge density of industrially manufactured hardwood and softwood grade kraft lignocellulosic fibers can mainly be attributed to carboxylic acid functionalities as determined from topochemical adsorption of a cationic polymer (methyl glycol chitosan) and the use of conductometric titration. These charge density measurement methods have led to a powerful and accurate photometric method for the quantitative analysis of surface charge. The method is based on directly monitoring the iodide ion, the counterion of the chitosan polymer, which is released upon electroneutralization between a chitosan cationic site and an anionic site at the fiber surface, thereby directly providing the concentration of surface charge. The stoichiometry for the chitosan adsorption onto the fiber surfaces is unity despite pulp types and adsorption quantity of cationic polymer. Given the high charge density of the chitosan molecule and the determined physical charge density limitations for its distribution onto the surface of pulps, a new and heretofore unused concept referred to as the subsurface was posited to adequately describe the surface charge determination after the adsorption of cationic polymer on the fibers. More specifically, within the subsurface of the suspended fibers in solution, carboxylates (COO −) were neutralized by the cationic sites of chitosan. The COO − sites in the subsurface can electrically attract positive sites of the cationic polymer, resulting in the complete release of counterions. To account for the charge density measurements, the charge measurement of the fibers includes not only nominal topochemical surface charges but also charges below this surface (subsurface).

Use of marker ion and cationic surfactant plastic membrane electrode for potentiometric titration of cationic polyelectrolytes

A plasticized poly (vinyl chloride) (PVC) membrane electrode sensitive to stearyltrimethylammonium (STA) ion is applied to the determination of cationic polyelectrolytes such as poly (diallyldimethylammonium chloride) (Cat-floc) by potentiometric titration, using a potassium poly (vinyl sulfate) (PVSK) solution as a titrant. The end-point of the titration is detected as the potential change of the plasticized PVC membrane electrode caused by decrease in the concentration of STA ion added to the sample solution as a marker ion due to the ion association reaction between the STA ion and PVSK. The effects of the concentration of STA ion, coexisting electrolytes in the sample solution and pH of the sample on the degree of the potential change at the end-point were examined. A linear relationship between the concentration of cationic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 2×10 −5 to 4×10 −4 N for Cat-floc, glycol chitosan, and methylglycol chitosan.

Determination of cationic polyelectrolytes using a photometric titration with crystal violet as a color indicator

The reaction of the cationic dye, crystal violet (CV) with the anionic polyelectrolytes such as potassium poly (vinyl sulfate) (PVSK) results in a decrease of the absorbance of CV at the maximum absorption wavelength (590 nm). This change of the absorption spectra of the CV has been already applied to the determination of anionic polyelectrolytes using flow injection analysis method. In this paper, CV was applied to the indicator for the determination of cationic polyelectrolytes such as poly (diallyldimethylammonium chloride) (Cat-floc) by photometric titration, using a PVSK solution as a titrant. The end-point of the titration is detected as the break point of the titration curve. A linear relationship between the concentration of cationic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 0 to 5×10 −5 eq. mol dm −3 for Cat-floc, glycol chitosan and methylglycol chitosan. The effects of the concentration of CV and coexisting electrolytes in the sample solution and the effect of pH of the sample solution on the degree of the change of absorbance at the end-point were also examined.

Synthesis of calcium silicate hydrate/polymer complexes: Part II. Cationic polymers and complex formation with different polymers

Some high molecular weight cationic polymers, poly(diallyldimethylammonium chloride) (PDC) and poly(4-vinylbenzyltrimethylammonium chloride) (PVC), have been incorporated into the calcium silicate hydrate (C–S–H) structure during precipitation of quasicrystalline C–S–H from aqueous solution. Expansion of the interlayer spacing [0.9 nm (PDC), 1.5 nm (PVC)] and a high-carbon content provided evidence that these polymers were intercalated between layers of C–S–H when Ca/Si <1.0. Intercalation characteristic properties strongly depended on both of the type of polymer and Ca/Si ratio in C–S–H. Poly(4-vinyl-1-methylpyridinium bromide) and methyl glycol chitosan (iodide) also interacted with C–S–H, probably by surface adsorption. The C–S–H/polymer complexes were examined by Fourier transform infrared spectroscopy, 29Si nuclear magnetic resonance magic angle spinning, and 13C cross-polarization, magic angle spinning nuclear magnetic resonance spectroscopy. Mechanisms of intercalation of different kinds of polymers between the C–S–H layers are discussed.

Preparation and properties of macromolecular complexes consisting of chitosan derivatives, iron(III) hydroxide sulfate, and poly(potassium vinyl sulfate)

AbstractGlycol chitosan (GC) and methyl glycol chitosan (MGC) were separately reacted with poly(potassium vinyl sulfate) (PVSK) in the presence of iron(III) hydroxide sulfate (IHS) to form water‐insoluble macromolecular complexes (MC's). The chemical compositions and properties of MC's obtained were compared with each other. The solubility of MC in the MGC‐IHS‐PVSK system was lower than that in the GC‐IHS‐PVSK system, and it was suggested that MGC contributes to the properties of MC.

Preparation and properties of macromolecular complexes consisting of chitosan derivatives and potassium metaphosphate

AbstractGlycol chitosan (GC) and methyl glycol chitosan (MGC) were, individually, reacted with potassium metaphosphate (MPK) to form a series of water‐insoluble macromolecular complexes (MC) in aqueous solution at different hydrogen ion concentrations (GC‐MPK and MGC‐MPK systems). GC was reacted with MPK in the presence of CaCl2 (GC‐MPK‐CaCl2 system) as well as in the absence of CaCl2. The properties of MC obtained were studied. On the basis of elemental analysis, solubilities, and thermogravimetry analysis, it is suggested that the molecular structure of each MC depends on the hydrogen ion concentration and whether Ca2+ ion is present or not. MC prepared at pH 1,0 are composed of a relatively loose network including a small quantity of MPK, whereas those MC prepared at neutral and higher pH are composed of a relatively tight network including a large quantity of MPK. As compared with MC in the GC‐MPK system, those in the GC‐MPK‐CaCl2 system are anticipated to have a rather tightly bound network structure due to the cross‐linkings through Ca2+ ions.

Permeability Control of Polyelectrolyte Complex Membrane Including Chitosan Derivative as a Component

Abstract The properties of polyelectrolyte complexes (PEC) and PEC membranes were investigated in the systems of glycol chitosan (GC)–poly(vinyl sulfate) (PVSK) and methyl glycol chitosan (MGC)–(carboxymethyl)dextran (CMD). The degree of dissociation and the conformation of GC and CMD depend upon pH, because GC and CMD are weak polybase and weak polyacid, respectively. On the basis of this knowledge, a research into the pH dependence of dissociation and viscosity of GC and CMD was carried out. PEC including chitosan derivative as a constituent was synthesized at the adequate pH, pH 3.0 in the GC–PVSK system and pH 7.0 in the MGC–CMD system. PEC membranes were prepared, and the permeability of KCl, urea, and sucrose through the GC–PVSK membrane was determined under various pH. It was revealed that the permeability of KCl, urea, and sucrose varies with the solution pH. The permeability in the neutral region was 2–10 times as high as that in acidic region. The increase of permeability in neutral region was considered from IR spectra of membranes to be due to swelling caused by a conformational change.

Structures, properties, and alkali metal ion transport membrane of polyelectrolyte complexes consisting of methyl glycol chitosan, glycol chitosan, and poly(vinyl sulfate)

AbstractMixtures of methyl glycol chitosan and glycol chitosan were reacted with poly(vinyl sulfate) to form many different water‐insoluble polyelectrolyte complexes (PEC) in aqueous solution at various hydrogen ion concentrations. It was revealed from elemental analyses, infrared (IR) spectroscopy, and solubilities of PEC that molecular structures of each PEC are dependent on [H+]. PEC membranes were made from casting solutions of all kinds of PEC, and transport phenomena through the membrane of PEC prepared in a pH 13.0 solution were investigated under various conditions. The transport ratio of Na+ and the electric potential difference between the left‐ and right‐hand sides of the membrane were measured, and it is suggested that the driving force for active transport depends on the membrane potential, Donnan potential and diffusion potential. Moreover, permeability of K+ was higher than that of Na+ in selective transport.

Properties of membranes from polyelectrolyte complexes consisting of methyl glycol chitosan, [2‐(diethylamino)ethyl]dextran, and poly(potassium vinyl sulfate)

AbstractWater‐insoluble polyelectrolyte complexes (PEC) were prepared by mixing methyl glycol chitosan (MGC, 1) and [2‐(diethylamino)ethyl]dextran (EA, 2) with poly(potassium vinyl sulfate) (PVSK, 3) in aqueous solution at various hydrogen ion concentrations. Elemental analyses, IR spectroscopy, and solubilities of PEC reveal that PEC differ in molecular structure and properties according to pH. It seems that the degree of dissociation and the conformation of MGC, EA, and PVSK change with pH. PEC membranes were made by casting from solutions of all kinds of PEC, and transport phenomena through the membrane of PEC prepared in 4 wt.‐% HCl solution were investigated under various conditions. The driving force of the transport depends on the membrance potential, Donnan potential, and diffusion potential, according to measurements of the transport ratio of Na+ and the electric potential difference between the left‐ and right‐hand side of the membrane. Moreover, the permeability of K+ is higher than that of Na+.

メチルグリコールキトサン，（カルボキシメチル）デキストランおよび硫酸エステル化ポリビニルアルコールからなる高分子電解質複合体膜の透過性 ＩＩ 標題複合体膜によるアルカリ金属イオンの能動輸送と選択透過

多糖類であるメチルグリコールキトザンと(カルボキシメチル)デキストラン,そして合成高分子である硫酸エステル化ポリピニルアルコールの3種類の高分子電解質から合成した水に難溶性な高分子電解質複合体を,キャスト法により成膜した。得られた高分子電解質複合体膜について,アルカリ金属イオンのNa+およびK+に対する能動輸送ならびに選択透過性を検討した。その結果,この膜は,能動輸送および選択透過機能をもっていることが明らかとなった。これは,水素イオン濃度差を騒動力とし,水素イオン濃度の変化にともなう膜の化学的性質の変化,およびキャリヤーの親和性に起因するものと推論される。

Studies on the bacterial spore coat. IX. The role of surface charge in germination of Bacillus megaterium spores.

The surface charge of Bacillus megaterium QM B1551 spores was estimated to be negative, -0.2 ad -0.4 mueq/mg by colloidal titration using glycol chitosan (GCh) and methylglycol chitosan (MGCh), respectively, as positive colloids. MGCh, which reacts with all of the negatively charged groups including carboxylate, inhibited the second stage of the germination to result in semirefractile spores, but GCh, which reacts only with strong acidic groups such as phosphate, did not. The spores produced in a medium with limited phosphate had coats with low phosphate content and carried less negative charge, and they were induced to germinate with 0.4 mM KNO3, which is one-tenth of the minimum concentration required for the germination of the control spores. A similar increase in germinability was observed in spores incubated with calcium acetate. The results suggest that the role of the surface charge in germination is as follows. Strong acidic groups (such as phosphate) in the coat may block the action of ionic germinants and act as a barrier against the initiation of ionic germination. Positively charged compounds (such as calcium) may compensate for this blocking effect. Weak acidic groups (such as carboxylate) may be involved in the later stage of germination.