Chitin Membranes Research Articles

Albumin separation with Cibacron Blue carrying macroporous chitosan and chitin affinity membranes

Cibacron Blue F3GA, Procion Red HE-3B and Procion Blue MX-R were immobilized on macroporous chitosan and chitin membranes with concentrations as high as 10–200 μmol/ml membrane. These dyed membranes were chemically and mechanically stable, could be reproducibly prepared, and operated at high flow rates. Human serum albumin (HSA) and bovine serum albumin (BSA) were selected as model proteins, and their adsorption on and desorption from the dyed chitosan membranes investigated. The Cibacron Blue F3GA membranes had a higher protein adsorption capacity, much greater for HSA than BSA, than the other dyed membranes. About 8.4 mg HSA/ml membrane were adsorbed at saturation by Cibacron Blue F3GA–chitosan membranes from a 0.05 M Tris–HCl/0.05 M NaCl, pH 8 solution. The chitin membranes had a lower dye content and hence a lower protein adsorption capacity than the chitosan membranes. The effects of important operation parameters (flow rate, protein concentration and loading) were also investigated. Cibacron Blue F3GA–chitosan membranes were employed for the separation of HSA from human plasma and high purity HSA thus obtained. This suggests that these membranes could be used for large-scale plasma fractionation.

Two-dimensional manipulation of confluently cultured vascular endothelial cells using temperature-responsive poly(N-isopropylacrylamide)-grafted surfaces

Temperature-responsive hydration/dehydration changes in surface-grafted poly(N-isopropylacrylamide) (PIPAAm) were utilized for hydrophilic/hydrophobic surface property alterations in cell culture. In this report, we utilized PIPAAm-grafted surfaces to recover confluently-cultured vascular endothelial cells as coherent monolayers from this cell culture substrate and to transfer to new cell culture substrates. For this purpose, we used two different methods to recover and transfer cell monolayer cultures: (1) chitin membranes used as an apical side cell support during cultured cell transfer, allowing cell basal side reattachment to new culture substrates after transfer; and (2) a cell culture insert™ (porous PET) used as both a support as well as new substrate, allowing basal surfaces of cultured cells to be exposed to the medium after transfer. In both cases, all cells grown on PIPAAm-grafted surfaces detach completely with maintenance of basement membrane-like structure. Recovered cells attach to the second culture surfaces, covering more than 60% of the new substrate, and retain approximately 90% viability and their original function as judged from tissue-type plasminogen activator secretion. This technique could be utilized to prepare novel bioartificial organs as well as cell co-culture systems by multi-layering different cell types to mimic tissue structures for tissue engineering.

Macroporous chitin affinity membranes for lysozyme separation

Macroporous chitin membranes with high, controlled porosity and good mechanical properties have been prepared using a technique developed in this laboratory based on silica particles as porogen. They were employed for the affinity separation of lysozyme. Chitin membranes (1 mm thickness) can be operated at high fluxes (≥1.1 mL/min/cm2) corresponding to pressure drops ≥2 psi. Their adsorption capacity for lysozyme (∼50 mg/mL membrane) is by an order of magnitude higher than that of the chitin beads employed in column separation. In a binary mixture of lysozyme and ovalbumin, the membranes showed very high selectivity towards lysozyme. The effect of some important operation parameters, such as the flow rates during loading and elution were investigated. Lysozyme of very high purity (>98%) was obtained from a mixture of lysozyme and ovalbumin, and from egg white. The results indicate that the macroporous chitin membranes can be used for the separation, purification, and recovery of lysozyme at large scale. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 610–617, 1997.

Macroporous chitin affinity membranes for lysozyme separation

Macroporous chitin membranes with high, controlled porosity and good mechanical properties have been prepared using a technique developed in this laboratory based on silica particles as porogen. They were employed for the affinity separation of lysozyme. Chitin membranes (1 mm thickness) can be operated at high fluxes (>/=1.1 mL/min/cm(2)) corresponding to pressure drops >/=2 psi. Their adsorption capacity for lysozyme ( approximately 50 mg/mL membrane) is by an order of magnitude higher than that of the chitin beads employed in column separation. In a binary mixture of lysozyme and ovalbumin, the membranes showed very high selectivity towards lysozyme. The effect of some important operation parameters, such as the flow rates during loading and elution were investigated. Lysozyme of very high purity (>98%) was obtained from a mixture of lysozyme and ovalbumin, and from egg white. The results indicate that the macroporous chitin membranes can be used for the separation, purification, and recovery of lysozyme at large scale. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 610-617, 1997.

Control of Pore Sizes in Macroporous Chitosan and Chitin Membranes

A novel method for the preparation of macroporous chitosan and chitin membranes is suggested, which employs silica particles as porogen. The macroporous chitosan membranes were prepared by (1) casting an acidic chitosan solution that contains silica particles, (2) removing the solvent by evaporation, and (3) dissolving the silica particles by immersing the membranes into an alkaline solution. This simple method provides chitosan membranes with high porosity and satisfactory mechanical strength, the pore sizes of which can be easily controlled by varying the size of silica particles. The effects of various evaporation conditions and amount of silica on the flow rate of water through the membranes were investigated. In order to prevent their dissolution in acidic solutions, the chitosan membranes were cross-linked under alkaline conditions, using epichlorohydrin as the cross-linking agent. Macroporous chitin membranes were prepared by acetylating the chitosan membranes with acetic anhydride in methanol. In contrast to the uncross-linked chitosan membranes, which are soluble in dilute acidic solutions and insoluble in alkaline solutions, the chitin membranes are insoluble both in acidic and basic solutions. Both kinds of membranes can be employed in affinity or ion-exchange bioseparations.

キチン上で培養したマクロファージ産生物のヒト歯肉由来線維芽細胞様細胞に及ぼす影響 炎症性メディエーターの解析

キチン上で培養したマクロファージ産生物のヒト歯肉由来線維芽細胞様細胞に及ぼす影響 炎症性メディエーターの解析

Development of an Enzyme Sensor Using Multi-enzyme System Immobilized in β-Chitin Membrane

Development of an Enzyme Sensor Using Multi-enzyme System Immobilized in β-Chitin Membrane

キチン創傷被覆保護材の歯科領域への応用

Many kinds of wound dressing biomaterials have been used for donor site, burn skin or graft site. A "chitin" wound dressing extracted from red "zuwai" crab has numerous advantages over freeze-dried dura, pig skin or fibrin membrane. This paper reported that the chitin membrane applied to mucosal defect after epulis dessections, and also to absorbable membrane for GTR method. As a result, good clinical courses were observed in the patients and this membrane was recognized as a usuful wound dressing biomaterial.

Studies upon the fine structure and selected physical and physicochemical properties of butrylchitin membranes

AbstractThe effect of varying the molecular weight of butyrylchitin membranes cast from methylene chloride on their properties has been investigated. Characterization analyses include X‐ray, scanning calorimetry and tensile stress‐strain. The crystal structure of the butyrylchitin was shown to consist of fringed micelles, irrespective of the molecular weights examined, and of lower crystal volume fraction than usually found for chitin membranes, 0.3 versus 0.5, respectively. The membranes exhibit greater ductility and less swelling in physiological salt solution with increasing molecular weight. © 1994 John Wiley & Sons, Inc.

コラーゲン・シリコーン複合体人工粘膜の口腔粘膜欠損部への臨床応用に関する検討

In recent years, freeze-dried dura, porcine skin, chitin membrane, and other materials have been used as occlusive wound dressings for burns, donor sites, graft sites, and oral mucosal defects. However, these are only temporary materials that have several disadvantages in terms of biocompatibility, infection, antigenicity, and breakdown.A new bilayer artificial mucous membrane (TERUDERMIS®, Terumo Co.) has been developed as a permanent material that promotes the reconstruction of tissue. It consists of a bottom layer of fibrillar collagen and heat-denatured collagen with dehydrothermal cross-linking, and an upper layer of a silicone elastomer.We used TERUDERMIS® successfully in the treatment of 32 patients in whom problems with the oral mucosa, including the gingiva and tongue, had developed during surgery. The material was found to be easy to handle, adhere well and promote hemostasis, relive pain, have little antigenicity, limit infection, promote rapid epithelialization, and produce newly, synthesized connective tissue with the infiltration of cellular tufts of fibroblasts and capillaries, and with minimum contraction.The results suggest that the material is safe and effective for clinical use, and merits being referred to as an “artificial mucous membrane.”

Effect of Chitin on the Production of Chemical Mediators by Peripheral Monocytes.

To investigate the mechanisms of the many favorable properties of chitin membrane in woundhealing, human peripheral monocytes were cultured on chitin membrane or other wound dressing materials, and the chemical mediators from macrophage, including prostaglandin E2 and interleukin 1, were analyzed.These mediators were detected in the supernatants of the macrophage cultures. The chitin-induced productionof chemical mediators from macrophages was less than that induced by the other dressing materials.These results suggest that each wound dressing material has a different capability of inducing th productionof inflammatory chemical mediators by macrophages, and that the favorable properties of chitin in woundhealing might be related to its lower capability to induce localized inflammation.

ラット創傷部に対するキチンの効果について

ラット創傷部に対するキチンの効果について

Simple and mild preparation of an enzyme-immobilized membrane for a biosensor using β-type crystalline chitin

A thin enzyme-immobilized membrane was prepared from squid pen chitin under simple and mild conditions. Squid pen chitin had better physical properties than crab chitin owing to the β-type crystalline structure in the former. The membrane exhibited not only the ability to entrap enzyme molecules but also sufficient oxygen and glucose permeabilities useful for biosensors. A glucose sensor, which was constructed with glucose oxidase immobilized on the chitin membrane and an oxygen electrode, exhibited a wide range of linearity (0.125–2.0 mM) and possessed good stability.

The hemostatic effect of deacetylated chitin membrane on peritoneal injury in rabbit model.

In this study, we determined the effect of 80% deacetylated chitin (DAC-80) membrane on postsurgical bleeding after visceral and parietal peritoneal abrasion. Japanese white rabbits underwent a midline laparotomy followed either by a bilateral peritoneal sidewall abrasion (4 x 4 cm) or an abrasion of liver surface (3 x 2 cm). The injured surface was then covered with a 0.2 mm thick DAC-80 membrane. On postsurgical day 2, the rabbits were sacrificed and the amounts of postsurgical bleeding was determined by quantitating the number of red blood cells recovered in 50 ml peritoneal lavage fluid. The DAC-80 membrane was found to reduce postsurgical bleeding after the abrasion of liver surface (treated with DAC-80 membrane: 2.9 +/- 0.8; control: 24.6 +/- 5.9 x 10(8) cells/peritoneal cavity, P less than 0.005). This same hemostatic activity was not observed after application in the peritoneal sidewall abrasion model. We also measured plasminogen activator activity (PA) and urokinase inhibitory (PAI) activity in the spent culture media of macrophages recovered from the postsurgical peritoneal exudate. The DAC-80 membrane reduced the PA secretion from postsurgical macrophages after liver surface abrasion (treated with DAC-80: 2.8 +/- 0.7; control: 3.9 +/- 0.9 mPU/ml). The DAC-80 membrane also showed similar effects on PA secretion after peritoneal sidewall abrasion. No significant effects were found in the secretion of PAI by postsurgical macrophages in both surgical models. These findings suggest that the DAC-80 membrane may have hemostatic activity through the modulation of fibrinolytic activity of peritoneal exudative macrophages.

Chitin biodegradation in sand dunes

Chitin membranes, chitosan membranes and crab shells were buried in a sand dune, and digested completely within 60 days in the summer season. They absorbed water up to five times their weight and were degraded by soil chitinase. The chitin membrane was more digestible than the chitosan membrane. An enhanced chitinase activity was found in the seedling growth of black-pine seeds coated with a depolymerized chitosan ( M r 3,000–5,000), and the activity 1.3–1.5 times higher than that of uncoated seeds. We discuss the ecological significance in connection of chitinous materials with plant tissues.

Studies on chitin 3—effect of coagulants and annealing on the preparation and the properties of chitin membrane

AbstractChitin membrane was prepared by casting a N,N‐dimethyl acetamide, N‐methyl 2‐pyrrolidone and lithium chloride (DMA‐NMP‐LiCl)solution of chitin and coagulating with several media. The effect of the coagulants on membrane formation was studied. 2‐Propanol was found to be more favourable than methanol, ethanol, acetone and mixtures of 2‐propanol and water. The membrane obtained in 2‐propanol was subjected to annealing. Annealing made the membrane dense and strong. The tensile strength of the membrane annealed at 145°C for 2hr was about twice that of an unannealed membrane. The solute permeability of the annealed membranes was lower than that of the original one. These phenomena could be clearly interpreted in terms of crystallinity.

Studies on chitin. 2. Preparation and properties of chitin membranes

A chitin membrane was prepared by a new procedure involving coagulation of the chitin solution in N,N-dimethyl acetamide, N-methyl 2-pyrrolidone and lithium chloride (DMA-NMP-LiCl) with 2-propanol. The solute permeability, water sorption and mechanical properties were compared with membranes prepared by two previously reported methods (coagulation of a formic acid and dichloroacetic acid (FA-DCA) solution of chitin with 2-propanol; and coagulation of a trichloroacetic acid and dichloroethane (TCA-DCE) solution of chitin with acetone). The permeability coefficients of the three chitin membranes were higher than a regenerated cellulose membrane (Cuprophane®). The membrane prepared from DMA-NMP-LiCl solution had a higher tensile strength (3·3 Mpa) in the wet state than the others. The membrane obtained from TCA-DCE solution absorbed more water (360%) and the membrane prepared from FA-DCA solution was relatively weak (1·8 MPa) in the wet state. It was suggested that 2-propanol was a favourable coagulant for membrane production. In addition, the effect of the origin of chitin on molecular weight and tensile properties of the membranes was studied.

Permeability of the integument of the horseshoe crab, Limulus polyphemus, to water, sodium, and bromide

AbstractMean water movements across the double chitin membrane of the Limulus gill are 5,000–7,000 μmoles/cm2 · h. The carapace is much less permeable to water than the gill; this difference is probably due primarily to the greater thickness of the carapace. Variations in serum sodium concentration due to salinity changes do not affect the rates of water diffusion across the gills or carapace. The cause of a substantial variation between individuals in integumental water permeability is unknown. The sodium influx across the carapace of Limulus (0.7–1.6 μmoles/cm2 · h) is only a fraction that of the unidirectional water flux under the same conditions (0.5 M NaCl on both sides). This difference may be attributed to the greater size of the sodium ion in solution. There is no apparent effect of variations in carapace thickness on the sodium influx. The double chitin gill membrane is similarly low in sodium and bromide permeability (about 0.5–0.6 μmole/cm2 · h). Thus it appears that the gills may have a relatively passive role in ionic regulation. Their low rates of ionic diffusion help to restrict the loss or intake of salts as the salinity changes. However, the high gill permeability to water must pose a severe problem for an animal coping with changes in external salinity.

Studies on syntheses and permeabilities of special polymer membranes: 35. Preparation and permeation characteristics of chitin membranes

Studies on syntheses and permeabilities of special polymer membranes: 35. Preparation and permeation characteristics of chitin membranes

Fecal excretion of cadmium and copper after mushroom (Agaricus) diet (author's transl)

High contents of cadmium in some agaricus species led to the warning that the eating of wild-grown mushrooms may bear the possibility of cadmium-intoxication. The low digestion rate due to the chitin membrane of fungi was not discussed. Therefore, in this investigation the cadmium- and copper-concentrations in feces of five subjects were estimated before and after a three days mushrooms diet. The high amount of fecal cadmium and copper increasing after the diet confirm the suggestion, that eaten fungi mostly pass through the intestinal tract unscathed without resorption. By this even larger ingestions of agaricus fungi may not cause cadmium intoxication in humans.