- Surface functionalization of chitosan isolated from shrimp shells, using salicylaldehyde ionic liquids in exploration for novel economic and ecofriendly antibiofoulants
-
Since the use of organotin as antifouling additives was prohibited in 2003, many researchers have endeavored to design and develop novel economic environment-friendly marine antifouling additives. This work reports the successful functionalization of biop
- Elshaarawy, Reda F. M.,Mustafa, Fatma H. A.,Herbst, Annika,Farag, Aida E. M.,Janiak, Christoph
-
-
Read Online
- Synthesis and characterization of N-propyl-N-methylene phosphonic chitosan derivative
-
A simple methodology for the preparation of a new chitosan derivative called N-propyl-N-methylene phosphonic chitosan (PNMPC) is proposed. Introduction of a propyl chain onto a modified chitosan (N-methylene phosphonic chitosan) offers the presence of hydrophobic and hydrophilic branches for controlling solubility properties of the new derivative. Its chemical identity was determined by FT-IR, 1H, 13C and 31P NMR spectroscopy. The degree of propyl substitution estimated by elemental analysis was 0.64. Furthermore derivative molecular weight is about 60 × 103, X-ray diffraction and SEM showed certain degree of crystallinity and homogeneous surface with a rather packed structure. This derivative opens new perspectives in food, pharmaceutical and cosmetic fields.
- Zu?iga, Adriana,Debbaudt, Adriana,Albertengo, Liliana,Rodríguez, María Susana
-
-
Read Online
- 2-Azido-2-deoxycellulose: Synthesis and 1,3-dipolar cycloaddition
-
Chitosan (1) was prepared by basic hydrolysis of chitin of an average molecular weight of 70000 Da, 1H-NMR spectra indicating almost complete deacetylation. N-Phthaloylation of 1 yielded the known N-phthaloylchitosan (2), which was tritylated to provide 3a and methoxytritylated to 3b. Dephthaloylation of 3a with NH2NH 2·H2O gave the 6-O-tritylated chitosan 4a. Similarly, 3b gave the 6-O-methoxytritylated 4b. CuSO4-Catalyzed diazo transfer to 4a yielded 95% of the azide 5a, and uncatalyzed diazo transfer to 4b gave 82% of azide 5b. Further treatment of 5a with CuSO4 produced 2-azido-2-deoxycellulose (7). Demethoxytritylation of 5b in HCOOH gave 2-azido-2-deoxy-3,6-di-O-formylcellulose (6), which was deformylated to 7. The 1,3-dipolar cycloaddition of 7 to a range of phenyl-, (phenyl)alkyl-, and alkylmonosubstituted alkynes in DMSO in the presence of CuI gave the 1,2,3-triazoles 8-15 in high yields.
- Zhang, Fuyi,Bernet, Bruno,Bonnet, Veronique,Dangles, Olivier,Sarabia, Francisco,Vasella, Andrea
-
-
Read Online
- Continuous production of oligofructose syrup from Jerusalem artichoke juice by immobilized endo-inulinase
-
A commercially available endo-inulinase from Aspergillus niger was successfully immobilized onto a chitin carrier with 66% yield. The immobilized endo-inulinase showed maximal activity at 65 °C that was 5 °C higher than the optimum temperature of the free
- Nguyen, Quang D.,Rezessy-Szabó, Judit M.,Czukor, Bálint,Hoschke, ágoston
-
-
Read Online
- Oral administration with chitosan hydrolytic products modulates mitogen-induced and antigen-specific immune responses in BALB/c mice
-
The aim of this study was to investigate whether oral administration in BALB/c mice with chitosan hydrolytic products including chitosan hydrolysate, LMWC and a chitooligosaccharide mixture (oligomixture), modulates mitogen-induced and antigen-specific immune responses. A water-soluble chitosan hydrolysate was obtained via cellulase degradation of chitosan, and a LMWC and the oligomixture were separated from this hydrolysate. In non-immunized mice, both the chitosan hydrolysate and oligomixture significantly increased the phagocytic activity of peritoneal macrophages. Three chitosan hydrolytic products significantly increased the mitogen-induced proliferation of splenocytes and Peyer's patch (PP) lymphocytes. LMWC and oligomixture up-regulated IFN-γ secretion, and induced predominantly Th1 cytokine secretion in splenocytes. In antigen-specific immunity, similar effects of the chitosan hydrolytic products were observed on augmenting ovalbumin (OVA)-, as well as mitogen-, induced proliferation of splenocytes harvested from OVA-immunized mice. Interestingly, oligomixture was the most potent chitosan hydrolytic product to elicit OVA-specific IgM, IgG, and IgA production, while LMWC was the most potent one to elevate splenic IFN-γ production and IFN-γ/IL-4 (Th1/Th2) ratio. These results provide the distinct immunomodulatory properties of chitosan hydrolytic products in response to mitogens and specific antigen, paving the way for further development and application of dietary chitosan hydrolytic products against immune disorders and infection.
- Chang, Shun-Hsien,Wu, Guan-James,Wu, Chien-Hui,Huang, Chung-Hsiung,Tsai, Guo-Jane
-
-
Read Online
- Extraction and physicochemical characterization of chitin and chitosan from Zophobas morio larvae in varying sodium hydroxide concentration
-
Large amount of sodium hydroxide (NaOH) is consumed to remove the protein content in chitin biomass during deproteinization. However, excessive NaOH concentration used might lead to the reduction of cost effectiveness during chitin extraction. Hence, the
- Soon, Chu Yong,Tee, Yee Bond,Tan, Choon Hui,Rosnita, Abdul Talib,Khalina, Abdan
-
-
Read Online
- Chitin and chitosan preparation from shrimp shells using optimized enzymatic deproteinization
-
Different crude microbial proteases were applied for chitin extraction from shrimp shells. A Box-Behnken design with three variables and three levels was applied in order to approach the prediction of optimal enzyme/substrate ratio, temperature and incubation time on the deproteinization degree with Bacillus mojavensis A21 crude protease. These optimal conditions were: an enzyme/substrate ratio of 7.75 U/mg, a temperature of 60 °C and an incubation time of 6 h allowing to predict 94 ± 4% deproteinization. Experimentally, in these optimized conditions, a deproteinization degree of 88 ± 5% was obtained in good agreement with the prediction and larger than values generally given in literature. The deproteinized shells were then demineralized to obtain chitin which was converted to chitosan by deacetylation and its antibacterial activity against different bacteria was investigated. Results showed that chitosan dissolved at 50 mg/ml markedly inhibited the growth of most Gram-negative and Gram-positive bacteria tested.
- Younes, Islem,Ghorbel-Bellaaj, Olfa,Nasri, Rim,Chaabouni, Moncef,Rinaudo, Marguerite,Nasri, Moncef
-
-
Read Online
- Novel hybrid chitosan blended MoO3-TiO2 nanocomposite film: Evaluation of its solar light photocatalytic and antibacterial activities
-
In the present study, we report newly synthesized TiO2 and MoO3-TiO2 nanocomposites and chitosan and chitosan-blended MoO3-TiO2 nanocomposite films by sol-gel and solution cast methods, respectively. The synthesized nanocomposite films were characterized by XRD, FT-IR, TG-DTA and FESEM with EDAX. The antibacterial activities of the prepared nanocomposite films were tested against E. coli using the well diffusion method. The photocatalytic activities of the materials were investigated against methyl orange dye as a model organic pollutant under the irradiation of solar light. Furthermore, the mechanical properties (tensile strength and elongation) were determined using a Universal Testing Machine. From the obtained results, it was concluded that the chitosan-blended MoO3-TiO2 nanocomposite film exhibited higher photocatalytic, antibacterial and mechanical properties than the other materials.
- Magesan,Sanuja,Umapathy
-
-
Read Online
- Characteristics of deacetylation and depolymerization of β-chitin from jumbo squid (Dosidicus gigas) pens
-
This study evaluated the deacetylation characteristics of β-chitin from jumbo squid (Dosidicus gigas) pens by using strongly alkaline solutions of NaOH or KOH. Taguchi design was employed to investigate the effect of reagent concentration, temperature, time, and treatment step on molecular mass (MM) and degree of deacetylation (DDA) of the chitosan obtained. The optimal treatment conditions for achieving high MM and DDA of chitosan were identified as: 40% NaOH at 90 °C for 6 h with three separate steps (2 h + 2 h + 2 h) or 50% NaOH at 90 °C for 6 h with one step, or 50% KOH at 90 °C for 4 h with three steps (1 h + 1 h + 2 h) or 6 h with one step. The most important factor affecting DDA and MM was temperature and time, respectively. The chitosan obtained was then further depolymerized by cellulase or lysozyme with cellulase giving a higher degradation ratio, lower relative viscosity, and a larger amount of reducingend formations than that of lysozyme due to its higher susceptibility. This study demonstrated that jumbo squid pens are a good source of materials to produce β-chitosan with high DDA and a wide range of MM for various potential applications.
- Jung, Jooyeoun,Zhao, Yanyun
-
-
Read Online
- Kinetics of base deacetylation of chitin and chitosan as influenced by their crystallinity
-
Structural properties of the initial and reprecipitated chitin and chitosan samples in dry and wet states were studied.
- Chebotok,Novikov,Konovalova
-
-
Read Online
- Effective deacetylation of chitin under conditions of 15 psi/121 °C
-
Deacetylation of chitin under autoclaving conditions (15 psi/121 °C) was evaluated for the preparation of chitosan under different NaOH concentrations and reaction times. Deacetylation was effectively achieved by treatment of chitin under elevated temperature and pressure with 45% NaOH for 30 min and a solids/solvent ratio of 1:15. Treated chitosan showed similar nitrogen content (7.42%), degree of deacetylation (90.4%), and molecular mass (1560 kDa) but significantly higher viscosity values (2025 cP) compared with those (7.40%, 87.6%, 1304 kDa, and 143 cP, respectively) of a commercial chitosan. Reduction of the solids/solvent ratio from 1:15 to 1:10 did not affect degree of deacetylation, viscosity, and molecular mass of chitosan.
- No, Hong Kyoon,Cho, Young In,Kim, Hyeung Rak,Meyers, Samuel P.
-
-
Read Online
- Effect of chitosan characteristics and solution conditions on gelation temperatures of chitosan/2-glycerophosphate/nanosilver hydrogels
-
In this study, we explored the effect of nanosilver, chitosan characteristics, and solution conditions on gelation temperatures of chitosan/2-glycerophosphate thermosensitive hydrogel. The gelation temperatures of hydrogels with or without 12 ppm nanosilver were insignificantly different regardless of the molecular weight (MW) of chitosan (degree of deacetylation, DD, 80% or 88%) and glycerophosphate concentration. The gelation temperature of hydrogel decreased with increasing DD (65-88%) of chitosan, increasing concentration of glycerophosphate (2-8%), and increasing pH value (6.5-6.8). It also decreased with decreasing chitosan's MW (DD88: 113-345 kDa, DD80: 145-900 kDa), but increased with increasing concentrations of NaCl (0-2%). By adjusting above conditions, the hydrogel gelation can be induced with a temperature range from 24.3 to 91.7 °C. Chitosan chains with higher flexibility and/or smaller hydrodynamic volume resulted in lower gelation temperature. Hydrogel became white turbidity in 2% NaCl below 38 °C because of its lower solubility at higher ionic strength.
- Tsai, Min-Lang,Chang, Hsiang-Wei,Yu, Hui-Chuan,Lin, Ya-Shen,Tsai, Ying-Die
-
-
Read Online
- Isolation of chitosan from shrimp shell (Metapenaeus monoceros) as adsorbent for removal of metanil yellow dyes
-
In this present study, chitosan derived from shrimp shells has been successfully extracted and employed as an adsorbent for metanil yellow dyes using the batch method. The yield of obtained chitosan was calculated as 75.22%, water content 8.9%, with %DD 66.81% based on the Baxter baseline method. The adsorption process indicated that the obtained chitosan reached optimum conditions at pH 4, initial concentration 1000?mg?L?1, contact time 60?min, adsorbent heating temperature 120?°C, adsorbent dosage 5?g?L?1, and particle size 25?μm with adsorption capacity 199.98?mg?g?1. The isotherm and kinetics studies revealed that the adsorption of metanil yellow onto chitosan was fitted to the Langmuir isotherm model and followed the pseudo-second-order model. The thermodynamic parameters (ΔG, ΔH, ΔS) indicated that the adsorption process was spontaneous and exothermic. The adsorption–desorption cycles revealed that NaOH 0.1?M has better performance as a desorbing agent after five adsorption–desorption cycles. The use of adsorbents derived from fishery solid waste in this system presents a sustainable effluent treatment method. The raw materials are derived from renewable natural product sources and are available in large quantities. This study revealed that the chitosan from shrimp shells has good potential as a low-cost and environmentally friendly adsorbent.
- Chaidir, Zulkarnain,Fauzia, Syiffa,Ramadhani, Putri,Zein, Rahmiana,Zilfa, Zilfa
-
-
- CONTROLLED RELEASE ENCAPSULATED ANTI-BACTERIAL AND ANTI-INFLAMMATORY NANOPARTICLES
-
This invention pertains to the formulation of nanoparticles that have intrinsic antimicrobial and anti-inflammatory activity. The nanoparticles can be impregnated with one or more therapeutic agents and thereby enhance the antimicrobial and/or anti-inflammatory activity of such agents, and also other properties that the therapeutic agents provide.
- -
-
Page/Page column 12
(2008/06/13)
-
- Structure having balanced pH profile
-
Disclosed is an absorbent structure comprising an acidic or basic water-swellable, water-insoluble polymer, a basic or acidic second material, and, optionally, a buffering agent, wherein the absorbent structure exhibits desirable absorbent properties. Specifically, the present invention relates to an absorbent structure having the ability to absorb a large quantity of liquid while maintaining a substantially desired and balanced pH profile on or along the upper surface of the absorbent structure. The absorbent structure is useful in disposable absorbent products, such as those disposable absorbent products that are used to absorb body liquid.
- -
-
Page/Page column 16
(2008/06/13)
-
- COMPOSITION AND FORMULATION OF COLLOIDAL SYSTEM COMPRISING BIOCOMPATIBLE AQUEOUS-SOLUBLE POLYMER, AND PREPARATION METHOD THEREOF
-
The present invention relates to an emulsion or cubosome composition sterically stabilized by including biocompatible polymers, an emulsion or cubosome formulation including the same composition and the preparation method thereof.
- -
-
Page/Page column 25-26
(2008/06/13)
-
- Cosmetic hair treatment process giving the hair long-lasting cosmetic properties
-
The invention relates to a cosmetic hair treatment process comprising non-reducing activation of the hair, and then applying to the activated hair at least one cosmetically active compound capable of forming a covalent bond with the activated hair with the aid of one or more functional groups of the compound.
- -
-
-
- Synthesis and characterization of a brush-like copolymer of polylactide grafted onto chitosan
-
A brush-like poly(DL)-lactide grafted onto chitosan as the backbone was investigated. The graft copolymerization was carried out with triethylaluminum as catalyst in toluene at 70°C. It was found that a greater lactide content in the feeding ratio results in a higher grafting percentage. FTIR spectrometry, 1H NMR, DSC scanning, and wide-angle X-ray scattering, respectively, are used to characterize these branch copolymers. A copolymer has a definite melting point when the molar feeding ratio of lactide to chitosan is more than 10:1, and the ΔH of the copolymers increases with the feed ratio of lactide to chitosan in feeding.
- Liu,Tian,Hu
-
p. 845 - 851
(2007/10/03)
-
- Formulation of an erodible, gastric retentive oral dosage form using in vitro disintegration test data
-
Erodible, gastric-retentive dosage forms are provided that are formulated using the in vitro drug release profile obtained with USP Disintegration test equipment rather the USP Dissolution Apparatus. The invention is premised on the discovery that the USP Disintegration Test and modified versions thereof are far more predictive of the in vivo release profile for a controlled release dosage form than is the standard USP Dissolution Test, particularly controlled release dosage forms of the swellable, erodible type. The dosage forms generally comprise particles of a biocompatible, hydrophilic polymer having the active agent incorporated therein, wherein the particles are optionally but preferably compacted into a tablet or loaded into a capsule. The dosage forms can be used to deliver water-insoluble or sparingly soluble drugs as well as water-soluble drugs, providing that the latter are coated with a protective coating or contained in a protective vesicle.
- -
-
-
- Formulation of an erodible, gastric retentive oral diuretic
-
An erodible, gastric-retentive oral diuretic is provided that is formulated using the in vitro drug release profile obtained with USP Disintegration test equipment rather the USP Dissolution Apparatus. The invention is premised on the discovery that the USP Disintegration Test and modified versions thereof are far more predictive of the in vivo release profile for a controlled release dosage form than is the standard USP Dissolution Test, particularly controlled release dosage forms of the swellable, erodible type. The dosage forms generally comprise particles of a biocompatible, hydrophilic polymer having the active agent incorporated therein, wherein the particles are optionally but preferably compacted into a tablet or loaded into a capsule. The dosage forms can be used to deliver water-insoluble or sparingly soluble drugs as well as water-soluble drugs, providing that the latter are coated with a protective coating or contained in a protective vesicle. Using the controlled release dosage form, adverse side effects associated with peak diuresis are diminished or eliminated, while the overall diuretic effect of the drug is maintained.
- -
-
-
- Formulation of an erodible, gastric retentive oral dosage form using in vitro disintegration test data
-
Erodible, gastric-retentive dosage forms are provided that are formulated using the in vitro drug release profile obtained with USP Disintegration test equipment rather the USP Dissolution Apparatus. The invention is premised on the discovery that the USP Disintegration Test and modified versions thereof are far more predictive of the in vivo release profile for a controlled release dosage form than is the standard USP Dissolution Test, particularly controlled release dosage forms of the swellable, erodible type. The dosage forms generally comprise particles of a biocompatible, hydrophilic polymer having the active agent incorporated therein, wherein the particles are optionally but preferably compacted into a tablet or loaded into a capsule. The dosage forms can be used to deliver water-insoluble or sparingly soluble drugs as well as water-soluble drugs, providing that the latter are coated with a protective coating or contained in a protective vesicle.
- -
-
-
- Conjugate, its preparation and use and a substrate prepared with the conjugate
-
The present invention relates to a water-soluble conjugate having antithrombin-binding activity comprising a substantially straight-chained organic polymer backbone having at least 30 molecules of sulfated glycosaminoglycans distributed along the polymer backbone, wherein the sulfated glycosaminoglycans are attached to the polymer backbone at a single point of attachment which is not responsible for the antithrombin-binding activity. The present invention also relates to a surface having antithrombin-binding properties prepared with the conjugate and methods of preparing said conjugate and said surface.
- -
-
-
- Method for separating lysozyme from egg-white
-
The present invention relates to a method for separating lysozyme from egg-white which has a lysozyme fraction and an albumin fraction, without destroying the commercial utility of the lysozyme fraction or the albumin fraction. The method comprises the step of preferentially, reversibly binding the lysozyme fraction of the egg-white to an affinity resin at about the natural pH of the egg-white by contacting the egg-white with the resin, separating the albumin fraction from the resin to leave the lysozyme fraction bound to the resin in a lysozyme-resin complex, and eluting the bound lysozyme from the resin to obtain a lysozyme solution and a reusable resin. The eluted lysozyme and the separated albumin fraction are further treated in separating processing lines to produce a commercial albumin fraction egg-white product and a commercial lysozyme product. The invention also deals with the preparation and compositions of suitable affinity resins for the reversible, preferential binding of lysozyme in egg-white.
- -
-
-
