Chitosan Sulfate Research Articles

Formation of Polyelectrolyte Multilayers by Flexible and Semiflexible Chains

Poly(sodium 4-styrene sulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDDA) are flexible polyelectrolytes, whereas sulfated chitosan (SC) and cationic guar gum (CGG) are semiflexible polyelectrolytes. By use of a quartz crystal microbalance with dissipation (QCM-D), a zeta potential analyzer (ZPA), and atomic force microscopy (AFM), we have investigated the growth of PSS/PDDA, PSS/CGG, SC/PDDA, and SC/CGG multilayers as a function of NaCl concentration (C(NaCl)). For the same layer number, the changes of frequency (-Δf) and dissipation (ΔD) regarding PSS/PDDA multilayer increase with C(NaCl), whereas -Δf and ΔD for SC/CGG multilayer increase at C(NaCl) < 0.1 M and decrease at C(NaCl) > 0.1 M as C(NaCl) increases. In the cases of PSS/CGG and SC/PDDA multilayer, for the same layer number, -Δf and ΔD increase with C(NaCl) in the range of C(NaCl) < 0.5 M, and they decrease with the increasing C(NaCl) in the case of SC/PDDA multilayer but slightly change for the PSS/CGG multilayer at C(NaCl) > 0.5 M. QCM-D studies indicate that the growth of multilayers as a function of salt concentration is determined by the delicate balance between the weakening of electrostatic repulsion between identically charged groups and the decrease of electrostatic attraction between neighboring layers. ZPA and AFM measurements demonstrate that the extent of surface charge overcompensation and the surface morphology of the multilayers are controlled by the chain conformation.

Extraction, characterization and in vitro antioxidative potential of chitosan and sulfated chitosan from Cuttlebone of Sepia aculeata Orbigny, 1848

ObjectiveTo investigate antioxidant potency of chitosan and sulfated chitosan in various established in vitro systems, such as superoxide (O2-)/hydroxyl (-OH) radicals scavenging, reducing power, metal ion chelating. MethodsChitosan was prepared from deacetylation of chitin from cuttlefish. FTIR, degree of acetylation and mineral studies was carried out from the chitosan. Chitosan was converted into sulfated chitosan using DMF/HClSO3 and their antioxidant activity was tested. ResultsMineral content of chitosan was Ca – 30 ppm, Na- 0.092 ppm, Cu-0.172 ppm, Mg- 3.601, Mn- 0.264 and Zn- 0.924 ppm, DA was 49.9% (IR spectroscopy) and 40.56% (UV spectrophotometer) recorded. Cuttlefish chitosan showed high level of superoxide radical scavenging activity (88.6%) and hydroxyl radical scavenging activity (72.1%), moderate activity was noted in chelating activity (62.6% at 100 μgm/mL). At the same time low level of reducing power was observed (0.300 Absorbance at 0.75 mg/mL) when compared to standard BHA and Ascorbic acid (2.305 and 2.05 Absorbance). ConclusionsFinally, the scavenging rate, reducing power, chelating and reducing power of sulfated chitosan increased with their increasing concentration.

Dipolar-molecule complexed chitosan carboxylate, phosphate, and sulphate dispersed electrorheological suspensions

Herein, the electrorheological (ER) properties of highly dispersion-stable, biocompatible and biodegradable chitosan derivative dispersed ER suspensions are explored. Electro-mechanical responses of the ER suspensions are enhanced with fixed spacers (amide and ester groups) and various functional groups (acid series and their complex forms with urea). A noteworthy result is that the shear stress of urea complexed chitosan acid dispersed suspensions was higher than before doping the urea molecule. However, urea complexed chitosan phosphate and sulphate showed a decreased tendency of shear stress due to too high conductivity at the high temperature. In the dispersion stability test, the chitosan dispersed suspensions showed high dispersion stability for long times. The study of the influence of dipolar molecules on the ER properties of the chitosan derivative dispersed suspensions under an electric field shows how to enhance the ER responses easily just by doping molecules.

Enhanced Healing of Rat Calvarial Defects with Sulfated Chitosan-Coated Calcium-Deficient Hydroxyapatite/Bone Morphogenetic Protein 2 Scaffolds

Calcium phosphate cements (CPCs), which are widely used in bone regeneration, possess good biocompatibility and osteoconductivity and have been demonstrated to be candidate carriers for bone growth factors. However, limited release of growth factors from CPCs and slow degradation of the materials are not desirable for certain clinical applications. Previous studies have shown that calcium-deficient hydroxyapatite (CDHA) from CPCs presents more rapid degradation rate than CPCs. In this study, a hybrid growth factor delivery system was prepared by using bone morphogenetic protein 2 (BMP-2) loaded CDHA porous scaffold with sulfated chitosan (SCS) coating for improved release profile. We tested the BMP-2 release characteristic of CDHA/BMP-2/SCS composite in vitro and its ability to repair rat calvarial bone defects. A higher percentage of BMP-2 was released when sulfated chitosan coating was present compared with CDHA/BMP-2 group. Eight weeks postoperation, the repaired crania were evaluated by microcomputed tomography, sequential fluorescent labeling, histological analysis, and immunohistochemistry. CDHA/BMP-2/SCS group promoted the most extensive new bone formation than CDHA/BMP-2 and CDHA groups. Our observations suggest that sulfated chitosan coating could enhance the release profile of CDHA/BMP-2 composite in vitro and promote new bone formation in vivo. The hybrid CDHA/BMP-2/SCS system is a promising growth factor delivery strategy for bone regeneration.

Self-assembly and liver targeting of sulfated chitosan nanoparticles functionalized with glycyrrhetinic acid

A drug carrier based on glycyrrhetinic acid-modified sulfated chitosan (GA-SCTS) was synthesized. The glycyrrhetinic acid (GA) acted as both a hydrophobic group and a liver-targeting ligand. The GA-SCTS micelles displayed rapid and significant ability to target the liver in vivo. The IC50 for doxorubicin (DOX)-loaded GA-SCTS micelles (DOX/SA-SCTS micelles) against HepG2 cells was 54.7 ng/mL, which was extremely lower than the amount of no-GA-modified DOX-loaded micelles. In addition, DOX/SA-SCTS micelles could target specifically the liver cancer cells. They had higher affinity for the liver cancer cells (HepG2 cells) than for the normal liver cells (Chang liver cells). There was nearly 2.18-fold improvement in uptake of the DOX/SA-SCTS micelles by HepG2 cells than that by Chang liver cells. These results indicate that GA-SCTS is not only an excellent carrier for drugs, but also a potential vehicle for liver-cancer targeting. From the Clinical EditorIn this basic science study, sulfated chitosan nanoparticles were functionalized with glycyrrhetinic acid and studied in cell cultures, demonstrating efficient self-assembly and targeting of liver pathology. In vivo demonstration for the same is also provided, paving the way to future studies establishing long-term effects, toxicity and potential clinical applicability.

Coagulation–flocculation of colloidal suspensions of kaolinite, bentonite, and alumina by chitosan sulfate

AbstractThis article reports on the removal of colloidal suspensions of kaolinite, bentonite, and alumina using chitosan sulfate (ChS). ChS was synthesized by partial introduction of sulfate groups in the chitosan (Ch) structure. The polyampholyte (chitosan sulfate) shows variable charge depending on the pH of the solution. ChS was characterized by FTIR, 13C‐NMR, elemental analysis, and potentiometric titrations. The ChS coagulation–flocculation capacity for kaolinite, bentonite, and alumina aqueous suspensions was systematically studied. The coagulation–flocculation process was carried out at various pH values and ChS concentrations. The pH range in which the largest ChS removal capacity was observed depended on particle type (4.5–5.5 for kaolinite, 4.5–7.0 for bentonite, and 7.0–8.0 for alumina). The removal of colloidal particles is explained by charge neutralization due to electrostatic interactions between ChS and particles and particle entrapping when the polyelectrolyte precipitates. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Modulation of osteogenic activity of BMP-2 by cellulose and chitosan derivatives

Polysaccharides with structure and potential bioactivity similar to heparin were synthesized based on cellulose which was regioselectively sulfated, carboxylated or carboxymethylated, and chitosan that was sulfated only. Osteogenic activity of these derivatives was studied in cooperation with BMP-2 using C2C12 myoblast cells as a model system measuring alkaline phosphatase (ALP) activity and the expression of the genes Osterix, Noggin and Runx-2. It was found that highly sulfated chitosan showed the strongest osteogenic activity of all polysaccharides, but only at lower concentrations, while higher concentrations were inhibitory. By contrast, cellulose with a low or intermediate degree of sulfation showed increasing ALP activity and expression of Osterix and Noggin with rising concentrations. Lower sulfated cellulose with a high degree of carboxylation was less osteogenic, but had a positive effect on cell viability, while carboxymethylated cellulose had almost no osteogenic activity. The results indicate that regioselectively sulfated as well as carboxylated cellulose and chitosan possess an osteogenic activity, which makes them interesting candidates for application in tissue engineering of bone.

Submicroparticles composed of amphiphilic chitosan derivative for oral insulin and curcumin release applications

Amphiphilic polymers for dual drug delivery have been a focus of research in recent years. We have previously developed and characterized Lauroyl sulphated chitosan (LSCS). Here biological characterizations like mucoadhesion, cytotoxicity, calcium binding, tight junction opening and enzymatic degradation studies were performed to understand its applicability. In vitro drug release properties of both hydrophilic insulin and hydrophobic curcumin were carried out. The biological activity and stability of released insulin were also studied. The stability studies of encapsulated curcumin and uptake studies have also been carried out. LSCS showed strong mucoadhesion and 100% of non-toxicity. LSCS could transiently open tight junctions between Caco-2 cells and thus increase the paracellular permeability. LSCS enhanced calcium binding properties and decreased enzymatic degradation rate retaining insulin activity. LSCS could protect curcumin from photodegradation and could also enter into the cells. From release studies, LSCS was found to be a suitable candidate for both drugs.

Post-treatment of biologically treated wastewater of agrochemical industry by sulfated chitosan composite nanofiltration membrane

The objective of this study is to treat the biologically treated wastewater using sulfated chitosan/ polyacrylonitrile (PAN) composite nanofiltration (NF) membrane to improve agrochemical industry wastewater quality for reuse. Although biological treatment is quite efficient, the wastewater does not meet the reuse criteria. Hence, further treatment to improve the water quality is investigated. Sulfated chitosan composite NF membranes, having a PAN ultrafiltration membrane as the substrate, are prepared by coating and cross-linking methods. The effects of membrane preparation conditions on the rejection and permeation performance of the membranes are studied. The new membranes are characterized by NMR and scanning electron micrograph. Wastewater from agrochemical industry contains high concentrations of organic matter, color, heavy metals and other toxic substances. The operating variables studied are applied pressure (3-15 atm) and feed flowrate (4-16 L/min). It is found that the observed rejection (R(o)) increases with increase in feed pressure at constant feed flowrate. The rejection of cations follows the sequence: R(o)(Zn2+) > R(o)(Ni2+) > R(o)(CU2+) > R(o)(Cd2+) for wastewater. It is observed that the order of solute rejection sequence is inversely proportional to the diffusion coefficients.

Sulfation of chitosan oligomers enhances their anti-adipogenic effect in 3T3-L1 adipocytes

Inhibition of adipogenesis and lipid accumulation has a very crucial role to prevent obesity. Low molecular weight (LMW) chitosan is known to inhibit fat accumulation and adipogenesis. (N,O)-sulfated chitosan is a sulfation derivative of chitosan oligomers, and its anti-obesity effect is not yet reported. In this study, it has been reported that (N,O)-sulfated chitosan significantly decreased lipid accumulation, an indicator for adipogenesis, in differentiating 3T3-L1 preadipocyte cells. Furthermore, mRNA expressions and protein levels of key adipogenic markers such as peroxisome prolifetor-activated receptor (PPAR)-γ and CCAAT-enhancer binding protein (C/EBP)-α were considerably decreased by (N,O)-sulfated chitosan treatment. As a consequence, sulfation of LMWC remarkably increased its effect of adipogenesis inhibition, adding (N,O)-sulfated chitosan high potential to be utilized as a bioactive agent in food and pharmaceutical industry.

Chitosan as an adjuvant for poliovaccine

The use of inactivated poliomyelitis vaccine is very important for eradicating poliomyelitis. However, this vaccine is not available readily in underdeveloped countries due to the high cost. Adjuvants can improve the immunogenicity of a vaccine and reduce the antigen dose required for vaccination, thus lowering the cost of the vaccine. Chitosan glutamate solution and a chitosan sulfate micro/nanoparticle suspension were tested as adjuvants for Imovax-inactivated poliovaccine and for inactivated monovalent poliovirus type 1, 2, and 3 vaccines obtained by inactivation of the attenuated Sabin poliovirus strains. Inactivated vaccines admixed with either chitosan glutamate or chitosan sulfate micro/nanoparticles and administered to mice showed significantly enhanced immunogenicity to poliovirus type 1, 2, and 3 strains compared to the respective vaccines administered without chitosan. Chitosan preparations increased the immunogenicity of 1:2 and 1:4 diluted inactivated Sabin strain preparations in mice 8- to 16-fold, so that the neutralizing antibody titers after vaccination with adjuvanted diluted vaccine were equal to those obtained after vaccination with undiluted vaccine administered without chitosan. Neutralizing antibodies could be detected in sera of rats vaccinated with undiluted, 1:10, and 1:100 diluted Imovax vaccine admixed with chitosan sulfate micro/nanoparticles, although in the control group, vaccination only with the undiluted vaccine resulted in antibody production. These results show that the chitosan glutamate solution and chitosan sulfate micro/nanoparticle suspension can significantly improve the immunogenicity of various poliovaccines, and reduce the effective antigen dose.

Development of lauroyl sulfated chitosan for enhancing hemocompatibility of chitosan

Chitosan (CS) has received much attention as a functional biopolymer especially in pharmaceutical applications, but has serious limitations owing to its poor hemo-compatibility property. Present paper focuses on the chemical modification of CS in order to enhance hemocompatibility. Amphiphilic derivative (lauroyl sulfated chitosan, LSCS) was prepared by the inclusion of sulfo group (hydrophilic) and lauroyl group (hydrophobic) to CS backbone and particles were prepared by an ionic-gellation approach. Modification was confirmed by FTIR, NMR and zeta potential measurements and the microparticles were evaluated for its particle size, swelling properties and thermal behaviour. Blood compatibility studies like hemolysis, RBC, WBC, platelet aggregation studies, blood clotting time, protein adsorption and C3 protein depletion assay were carried out for these polymers using standard techniques and cytotoxicity studies were performed to understand its applicability. Negatively charged (-6.06 mV) LSCS submicroparticles (886 nm) were prepared in this study. Blood compatibility studies demonstrated that the amphiphilic modification improved the hemocompatibility of CS. RBC aggregation and hemolysis induced by CS were significantly reduced by this modification. Further amphiphilic modification was effective in reducing the protein adsorption on CS. LSCS derivatives were found to be non-toxic in L929 cell lines. From these studies, it appears that LSCS is a hemocompatible version of CS.

Removal of nitrogen and carbon organic matter by chitosan and aluminium sulphate

River and lake waters were separated into four fractions to study the removal of nitrogen and carbon organic matter using chitosan (CH) and aluminium sulphate (AS). The fractions were very hydrophobic acid, slightly hydrophobic acid, charged hydrophilic acid and neutral hydrophilic. The results showed that the whole and fractionated water from both sources have a markedly hydrophobic character. However, lake water had a lower NOM concentration than river water. The ratio of dissolved organic carbon and dissolved organic nitrogen (DOC/DON) and dissolved inorganic nitrogen to total dissolved nitrogen (DIN/TDN) were higher in the hydrophobic fraction from both sources. Similarly DOC, colour and ultraviolet absorbance at 254 nm (UV254) also presented higher values in the same fraction. Chitosan achieved the better results in the removal of NOM from Boaco water, whole and fractionated, whereas aluminium sulphate achieved better removal from Juigalpa water. DON and DIN were removed by aluminium to about 30%. The DOC/DON and DIN/TDN ratios decreased with both coagulants in whole waters from both sources. The hydrophobic fraction contributed most to the formation of trihalomethanes, slightly hydrophobic acid being the biggest contributor. Lake water led to less THM formation than river water.

NMR and FT Raman characterisation of regioselectively sulfated chitosan regarding the distribution of sulfate groups and the degree of substitution

Chitosan sulfates (CHS) were prepared with chlorosulfonic acid homogeneously and non-homogeneously. The total degrees of substitution (DS) ascribed to sulfate groups (DSS) were determined with elemental analysis and the partial DS at 6-O-position was estimated via 13C NMR. CHS with diverse total DSS and sulfation patterns were obtained according to the analysis. The effects of selected reaction parameters that can influence the distribution of sulfate groups were examined. The structure of CHS was then characterized with various NMR techniques, i.e. one- (1D-) and two-dimensional (2D-) NMR, and FT Raman spectroscopy. It was found that the primary hydroxyl groups were always predominantly sulfated for CHS prepared under homogeneous or non-homogeneous conditions and no sulfate groups at 2-N-position could be detected. Finally, the feasibility of using FT Raman spectroscopy as another alternative for determining the total DSS of CHS was presented.

Modulation of Aβ 42 fìbrillogenesis by glycosaminoglycan structure

The role of amyloid β (Aβ) peptide in the onset and progression of Alzheimer's disease is linked to the presence of soluble Aβ species. Sulfated glycosaminoglycans (GAGs) promote Aβ fibrillogenesis and reduce the toxicity of the peptide in neuronal cell cultures, but a satisfactory rationale to explain these effects at the molecular level has not been provided yet. We have used circular dichroism, Fourier transform infrared spectroscopy, fluorescence microscopy and spectroscopy, protease digestion, atomic force microscopy (AFM), and molecular dynamics simulations to characterize the association of the 42-residue fragment Aβ(42) with sulfated GAGs, hyaluronan, chitosan, and poly(vinyl sulfate) (PVS). Our results indicate that the formation of stable Aβ(42) fibrils is promoted by polymeric GAGs with negative charges placed in-frame with the 4.8-Å separating Aβ(42) monomers within protofibrillar β-sheets. Incubation of Aβ(42) with excess sulfated GAGs and hyaluronan increased amyloid fibril content and resistance to proteolysis 2- to 5-fold, whereas in the presence of the cationic polysaccharide chitosan, Aβ(42) fibrillar species were reduced by 25% and sensitivity to protease degradation increased ∼3-fold. Fibrils of intermediate stability were obtained in the presence of PVS, an anionic polymer with more tightly packed charges than GAGs. Important structural differences between Aβ(42) fibrils induced by PVS and Aβ(42) fibrils obtained in the presence of GAGs and hyaluronan were observed by AFM, whereas mainly precursor protofibrillar forms were detected after incubation with chitosan. Computed binding energies per peptide from -11.2 to -13.5 kcal/mol were calculated for GAGs and PVS, whereas a significantly lower value of -7.4 kcal/mol was obtained for chitosan. Taken together, our data suggest a simple and straightforward mechanism to explain the role of GAGs as enhancers of the formation of insoluble Aβ(42) fibrils trapping soluble toxic forms.

Fabrication and properties of pH-sensitive nanostructured polyelectrolyte microparticles loaded with insulin

Thorough investigation and comparative study were conducted for insulin-loaded microparticles fabricated by consecutive adsorption of polyanions (dextran sulfate and chitosan sulfate) and polycations (chitosan and protamine) onto protein microaggregates. The possible regulation of insulin release from the particles by variation in polyelectrolyte pairs, in the number of their adsorption cycles and in pH of media was demonstrated. For all studied cases the microparticles showed protective action towards insulin inactivation at acid pH values and protein release at pH > 5, corresponding to human gastro-intestinal conditions.

Adsorption of human serum albumin (HSA) on modified PET films monitored by QCM-D, XPS and AFM

The adsorption behavior of human serum albumin (HSA) on differently modified poly(ethylene terephthalate) (PET) model film surfaces was studied using the quartz crystal microbalance (QCM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) techniques. The aim was to evaluate the influence of different modifications of PET surfaces with selected polysaccharides (chitosan, fucoidan, chitosan sulfate) on HSA adsorption. As a first step, PET hydrophilicity was increased by alkaline hydrolysis. From these foils model PET films were prepared by the spin coating technique on a quartz crystal. Selected polysaccharides (chitosan, fucoidan and chitosan sulfate) were adsorbed from aqueous solutions on the PET surfaces. Adsorption of HSA on the films was monitored with QCM-D. The surface composition and morphology of the HSA covered PET films was analyzed using XPS and AFM. It was found that due to steric repulsion the chitosan, fucoidan and chitosan sulfate adlayers reduced HSA adsorption, especially in case of chitosan/fucoidan and chitosan/chitosan sulfate covered films.

Abstract No. 97: Embolization and endothelial ablation with chitosan and sotradecol sulfate: Preliminary results in an animal model

Abstract No. 97: Embolization and endothelial ablation with chitosan and sotradecol sulfate: Preliminary results in an animal model

Absorption capacity of blood neutrophils after injecting heifer calves with chitosan sulfate at different times relative to vaccination against leptospirosis

Subcutaneous injection of an aqueous chitosan succinate solution into heifer calves promotes an increase of the adaptation reserve of absorption capacity of neutrophils 1 month after vaccination against leptospirosis, which creates the prerequisites for a favorable state of the calves 2 months after vaccination. Injection of the preparation 3 days before vaccination is found to be most effective.

Effects of a chemically derived homo zwitterionic polysaccharide on immune activation in mice

In this study, a chemically modified homo zwitterionic polysaccharide (ZPS), sulfated chitosan, was used to examine its effects on murine immune response. The results showed that homoZPS could markedly promote the proliferation of both splenic T/B cells and adhesive cells. In particular, flow cytometry assay demonstrated that the sulfated chitosan could non-specifically activate CD3(+) and CD8(+) T cells proliferation in vitro. The effectiveness of sulfated chitosan as adjuvant was tested using bovine serum albumin (BSA) and diphtheria toxin (DT) as antigens and compared with that of aluminum hydroxide. The levels of specific antibodies to BSA and DT significantly increased after homoZPS vaccination. Both homoZPS and aluminum hydroxide adjuvants could protect mice against the attack of DT from edemas of spleen and tail. The present findings demonstrated the chemically derived homoZPS could be a potential candidate in the development of T-lymphocyte dependent vaccine adjuvants.