Chitosan Liquid Research Articles

Voltammetric determination of uric acid in the presence of ascorbic acid and dopamine using chitosan/ionic liquid composite electrode

A chitosan/ionic liquid composite electrode was prepared and used to determine uric acid (UA) in the presence of a large excess of ascorbic acid (AA) and dopamine (DA) by linear sweep voltammetry (LSV). The modified electrode shows large peak separations between DA, AA, and UA. Due to the existence of chitosan and ionic liquid in the composite, the modified electrode exhibits strong electrochemical catalytic activity toward the oxidation of UA. Under optimal conditions, the peak current is linearly dependent on the UA concentration in the range of 5 × 10−7–2 × 10−4 M in the presence of 5 × 10−4 M AA and 5 × 10−5 M DA with a correlation coefficient of 0.9978, and the detection limit is 5 × 10−8 M at a signal-to-noise ratio of 3. With good sensitivity and stability, the constructed sensor was applied in the determination of UA in human serum samples and satisfactory results were obtained.

OPTIMASI PENGGUNAAN ADSORBEN KITOSAN 0,9% TERHADAP DAYA SERAP AMONIAK DALAM AIR LIMBAH KILANG MINYAK OUTLET IMPOUNDING BASIN (OIB) PERTAMINA RU VI BALONGAN, INDRAMAYU

Products of petroleum of liquid waste can be caused pollution in the ocean. Waste contains of chemical element especially ammonia. High concentration of ammonia has toxicity for human and aquatic ecosystems. This Research was aimed to decrease concentration of ammonia by chitosan liquid. The research was conducted in Technological Laboratory of Pertamina RU VI Balongan Indramayu on March - April 2013. The Method of this research used randomized design with kind of treatments is 4 levels and 3 repetition. Treatments of this research used chitosan liquid 0,9% with different variation between chitosan liquid and sample of waste oil refinery, such as : (A) 4%; (B) 8%; (C)12%; (D)16%, with 30 minutes time contact. The largest decrease of ammonia contained in (C) 12% ± 12,83 mg/L (48,67%) and optimum adsorption is 10,28 % ± 13,87 mg/L (44,52%).

Electrochemical behaviors and simultaneous determination of guanine and adenine based on graphene–ionic liquid–chitosan composite film modified glassy carbon electrode

A graphene sheets (GS), ionic liquid (IL) and chitosan (CS) modified electrode was fabricated and the modified electrode displayed excellent electrochemical catalytic activities toward guanine and adenine. The transfer electron number (n) and the charge transfer coefficient (α) were calculated with the result as n=2, α=0.58 for guanine, and n=2, α=0.51 for adenine, which indicated the electrochemical oxidation of guanine and adenine on GS/IL/CS modified electrode was a two-electron and two-proton process. The oxidation overpotentials of guanine and adenine were decreased significantly compared with those obtained at the bare glassy carbon electrode and multi-walled carbon nanotubes modified electrode. The modified electrode exhibited good analytical performance and was successfully applied for individual and simultaneous determination of guanine and adenine. Low detection limits of 0.75μM for guanine and 0.45μM for adenine were obtained, with the linear calibration curves over the concentration range 2.5–150μM and 1.5–350μM, respectively. At the same time, the proposed method was successfully applied for the determination of guanine and adenine in denatured DNA samples with satisfying results. Moreover, the GS/IL/CS modified electrode exhibited good sensitivity, long-term stability and reproducibility for the determination of guanine and adenine.

A novel formaldehyde sensor containing AgPd alloy nanoparticles electrodeposited on an ionic liquid–chitosan composite film

A novel formaldehyde (HCHO) sensor fabricated by electrodeposition of AgPd alloy nanoparticles (NPs) on chitosan (Ch)–ionic liquid (IL, i.e., 1-octyl-3-methylimidazolium hexafluorophosphate, OMIM·PF6) films is developed. A scanning electron micrograph of the AgPd/Ch–IL composite film shows a uniform distribution of spherical AgPd NPs with particle sizes of 30–60nm. Energy-dispersive X-ray measurements indicate that the mass ratio of Pd and Ag in the alloy is 21:5. Cyclic voltammetric studies show that an electrode coated with the AgPd/Ch–IL composite film exhibits high electrocatalytic activity and stability towards electrooxidation of HCHO. The HCHO sensor exhibits linear behavior in the concentration range from 0.060mM to 20mM, allowing quantitative analysis of HCHO with a detection limit of 0.022mM (S/N=3).

Electrochemical myoglobin biosensor based on graphene–ionic liquid–chitosan bionanocomposites: Direct electrochemistry and electrocatalysis

A novel biocompatible sensing strategy based on a graphene (GR), ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) and chitosan (CTS) composite film for the immobilization of myoglobin (Mb) was adopted in this paper. The UV–vis and FT-IR spectroscopic results demonstrate that the Mb in the composite film maintained its native structure. The direct electron transfer properties and the bioelectrocatalytic activity of the Mb in the nanocomposite film were further investigated. The cyclic voltammetric results indicate that a pair of quasi-reversible redox waves appeared, thereby signifying that the direct electrochemistry of the Mb was realized in the nanocomposite film. This result can be attributed to the specific properties of the material used, including the large surface-to-volume ratio and high conductivity of the GR, the high ionic conductivity of the IL, the interaction of the IL with the GR, and the high biocompatibility of the CTS, which enhanced the absorption of the Mb and promoted the direct electron transfer between the Mb and the substrate electrode. The CTS–Mb–GR–IL modified electrode exhibited a high electrochemical catalytic ability to reduce trichloroacetic acid, which demonstrates the material's potential application in third-generation biosensor.

Chitosan liquid improves wound healing in rats

Objective To study the promotive effect of chitosan liquid on wound healing.Methods Wound model was established on the back of 60 rats,which were classified into 3 groups to be treated with topical chitosan liquid (group A),basic fibroblast growth factor (group B),and sodium chloride physiological solution (group C),respectively.The time required for the healing of wound was recorded.Regenerated tissues were resected from the rats on day 3,7 and 14 after the establishment of wound model,and observed with light microscopy.Results The time required for the healing of wound was 17.3 ± 1.35 days in group A,18.2 ± 1.15 days in group B,and 24.0 ± 1.37 days in group C.For the time required for the healing of wound,no significant difference was observed between the group A and B (P ＞ 0.05),but group C significantly differed from group A and B (both P ＜ 0.05).Chitosan liquid accelerated the generation of capillary sprouts and vascular endothelial cells at the early stage of wound healing,promoted the production of fibroblasts and collagen fibers at the middle stage,and improved the organization of collagen fibers at the late stage.Conclusion Chitosan liquid exerts a promising promotive effect on wound healing.

Study on Chitosan Food Preservatives Technology

With the improvement of living standards, the requirement of food quality, nutrition, and freshness have been higher and higher. As the characteristics of highly effective, non-toxic, low cost, easy operation and significantly preservation effect, chitosan has been used widely as a new type of natural antistaling agent. Chitosan fresh-keeping mechanism and application in food preservatives are discussed in this study. From the three aspects of chitosan coating, composite coating, and chitosan modification, this work provides an overview of some researches about chitosan fresh food technology in abroad and domestic. And further development is discussed: the effect of the sole use of chitosan is not very good. Composite coating of chitosan will be more and more attractive with the merits about effectively preventing moisture loss, reducing weightlessness rate and so on. Storage stability about liquid chitosan can be solved by modified chitosan, which will also have a more attractive effect. This paper has theoretical significance to develop chitosan applications in food fresh-keeping technology.

Electrodeposition of gold–platinum alloy nanoparticles on ionic liquid–chitosan composite film and its application in fabricating an amperometric cholesterol biosensor

An electrodeposition method was applied to form gold–platinum (AuPt) alloy nanoparticles on the glassy carbon electrode (GCE) modified with a mixture of an ionic liquid (IL) and chitosan (Ch) (AuPt–Ch–IL/GCE). AuPt nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical methods. AuPt–Ch–IL/GCE electrocatalyzed the reduction of H 2O 2 and thus was suitable for the preparation of biosensors. Cholesterol oxidase (ChOx) was then, immobilized on the surface of the electrode by cross-linking ChOx and chitosan through addition of glutaraldehyde (ChOx/AuPt–Ch–IL/GCE). The fabricated biosensor exhibited two wide linear ranges of responses to cholesterol in the concentration ranges of 0.05–6.2 mM and 6.2–11.2 mM. The sensitivity of the biosensor was 90.7 μA mM −1 cm −2 and the limit of detection was 10 μM of cholesterol. The response time was less than 7 s. The Michaelis–Menten constant ( K m) was found as 0.24 mM. The effect of the addition of 1 mM ascorbic acid and glucose was tested on the amperometric response of 0.5 mM cholesterol and no change in response current of cholesterol was observed.

Antimicrobiai bioceramic combined with chitosan and ceftriaxone sodium:Preparation and its in vitro and in vivo study

Objective To synthesize antimicrobial bioceramic using chitosan and calcium phosphate cements mixed with ceftriaxone sodium. Methods The bioceramic was synthesized through the hardening of chitosan liquid combined with calcium phosphate cements and cefiriaxone sodium.The released ceftriaxone sodium was studied according to the linear equation between UV-VIS absorbance to concentration.The in vitro bactefiostatic effect of the chosen bioceramic was investigated via the microbiological method.The model of rats'contaminated bone defect were deployed to study the antimicrobial performance of the bioceramic. Results The best synthesis condition was chosen at:0.1g calcium phosphate cements and 10.4 mg ceftriaxone sodium combined with 2.4 ml hardening liquid C.then keeping the mixture at 60℃ and 100%humidity for 24 h.In vitro release of the resulting antimicrobial bioceramic remained stable,while that of ceftriaxone sodium lasted for a week,higher than the minimal inhibitory concentration(MIC) of Staphylococcus aureus.As proved by the WBC number and tissue sectioning,a lighter inflammatory response of treatment group was observed as compared with the control group. Conclusion The antimicrobial bioceramic combined with chitosan and ceftriaxone sodium shows promising antimicrobial performance. Key words: Chitosan; Ceftriaxone sodium; Bioceramics; BMP; Osteogenesis

Immunoassay channels for α -fetoprotein based on encapsulation of biorecognition molecules into SBA-15 mesopores

A novel immunoassay channeling sensor for α-fetoprotein (AFP) was proposed by incorporating biorecognition molecules into the mesopores of well-ordered hexagonal SBA-15. As the biosensing element, alkaline phosphatase (ALP)-labeled antibody was embedded into the mesopores with the substrate of 1-naphthyl phosphate (1-NP). The encapsulated ALP-labeled antibody retained its bioactivities on catalytic hydrolysis reaction with 1-NP and immunological reaction with antigen. Ionic liquid–chitosan hybrid was chosen to increase film adherence and prevent the leakage of the immobilized molecules. The peak current responses decreased due to the increasing spatial blocking and impedance from the formation of nonconductive immunoconjugates on the surface of the electrode. The experimental parameters were optimized including the concentrations of the immobilized 1-NP and ALP-labeled antibody, and the amounts of SBA-15 and ionic liquid for the electrode modification. Under the optimized conditions, the constructed immunosensor could detect AFP in a linear range from 1.0 to 150 ng mL −1 with a detection limit of 0.8 ng mL −1. It provided an alternative strategy for the detection of antigens or other proteins by the mesoporous materials.

Liquid‐crystalline behavior of chitosan in malic acid

AbstractThis report describes how the degree of deacetylation and molecular weight of chitosan and the concentrations of sodium chloride and malic acid affect the formation of lyotropic chitosan liquid crystals. Chitosan samples of various degrees of deacetylation were prepared from β‐chitin that was isolated from squid pens. They were degraded by ultrasonic irradiation to various molecular weights. The critical concentrations forming chitosan liquid crystals were determined with a polarized microscope. A chitosan sample with a degree of deacetylation of 67.2–83.6% formed cholesteric lyotropic liquid crystals when it was dissolved in 0.37–2.59M malic acid. The critical concentrations increased with increasing degrees of deacetylation of chitosan. They decreased with increasing molecular weights or increasing concentrations of sodium chloride and malic acid. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Effects of surfactant and acid type on preparation of chitosan microcapsules

Chitosan microcapsules were prepared by a method involving emulsification and crosslinking. The effects of surfactants and acid type for dissolving chitosan on the characteristics of chitosan microcapsules were investigated. The results showed that the mixed surfactant consisting of Span80 and Tween60 had an obvious effect on reducing the size of the microcapsules. The two-surfactant complex, formed on the basis of hydrogen bonding, strengthened the interfacial membrane in the emulsion, thus decreasing not only the size of the microcapsules but also the coalescence of dispersed chitosan liquid drops. In the case of monoacid such as hydrochloric acid or acetic acid for dissolving chitosan, the chitosan microcapsules obtained were spherical in shape with smooth surfaces. For diacids or triacid, the chitosan microcapsules obtained were also spherical, but their surfaces were covered by folds and crinkles. The number of carboxyl groups in the acids used influenced the chemical crosslinking between chitosan and the crosslinker (glutaraldehyde) as well as the morphology of the particles. For diacids or triacid, physical crosslinking occured due to electrostatic force, accompanied by substantial decrease of covalent crosslinking, leading to decreased strength of the microcapsules as shown by the collapse of microcapsule walls and the formation of multiple folds and crinkles on their surfaces.

Chitosan‐Alginate Complex Coacervate Capsules: Effects of Calcium Chloride, Plasticizers, and Polyelectrolytes on Mechanical Stability

AbstractA method has been developed to form capsules with liquid cores where permeability can be modified without sacrificing membrane strength. The capsule is formed by dropwise addition of a 3% chitosan (polycation) solution into a 0.75% alignate (polyanion) solution. The resultant capsule consists of a liquid chitosan core with a hard alginate coating. The addition of CaCl2 to chitosan and glucose to alginate increased capsule strength. The membranes formed were strong enough to require up to 100 Newton during uniaxial compression to burst a 6.4 mm diameter capsule.