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ABSTRACT: Six kinds of Bifidobacterium bifidum microcapsules were prepared by extrusion methods, emulsion methods and coacervation methods. Effects of preparation methods on the survival of encapsulated B. bifidum were examined. Results showed that microcapsules prepared by emulsion method with alginate and chitosan exhibited the best protection for B. bifidum. The diameter was 10-20 µm, encapsulation efficiency was 90.36% and the live cell amount was 3.01 × 10(9) cfu/g after freeze-drying. Encapsulated cells exhibited significantly higher resistance to artificial gastrointestinal juice and the cell numbers were above 10(9) cfu/g after exposure to simulated gastric (pH 1.2) and bile salt (1%, w/v). Cell numbers of microencapsulated B. bifidum was 8.61 × 10(8) cfu/g after storage at 37°C, relative humidity 60%-65% for 3 months. Results indicated microcapsules prepared with alginate and chitosan by emulsion method could successfully protect B. bifidum against adverse conditions and it might be useful in the delivery of probiotic cultures as a functional food.
Journal of Microencapsulation 02/2013; · 1.55 Impact Factor
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ABSTRACT: Oleoyl-carboxymethyl-chitosan (OCMCS) was synthesized and were soluble at neutral pH. The critical micelle concentration (CMC) of OCMCS in deionized water was 0.021mg/ml. OCMCS nanoparticles were successfully prepared via self-assembly with mean diameter of 215.34nm, zeta potential of 19.26mV and an almost spherical shape as determined by electron microscopy. The OCMCS nanoparticles showed low erythrocyte membrane-damaging effect. The MTT survival assay indicated no significant cytotoxicity to Caco-2 cells and MEFs cells. The uptake of FITC labeled OCMCS nanoparticles by Caco-2 cells was confirmed via confocal laser scanning microscope (CLSM). In vivo toxicity assays were performed via histopathological evaluation, and no specific anatomical pathological changes or tissue damage was observed in the tissues of carps. The extent of tissue distribution and retention following oral administration of FITC-OCMCS nanoparticles was analyzed for 3 days. After 3 days, the nanoparticles remained detectable in the muscle, heart, kidney, liver, intestine, and spleen. The results showed that 34.32% of the particles were localized in the liver, 18.79% in the kidney, and 17.36% in the heart. The lowest percentage was observed in the muscle. These results implied that OCMCS nanoparticles had great potential to be applied as safe carriers for the oral administration of protein drugs.
Colloids and surfaces. B, Biointerfaces 11/2012; 103C:345-353. · 2.60 Impact Factor
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ABSTRACT: Oleoyl-carboxymethy chitosan (OCMCS) nanoparticles based on chitosan with different molecular weights (50, 170 and 820 kDa) were prepared by self-assembled method. The nanoparticles had spherical shape, positive surface charges and the mean diameters were 157.4, 274.1 and 396.7 nm, respectively. FITC-labeled OCMCS nanoparticles were internalized via the intestinal mucosa and observed in liver, spleen, intestine and heart following oral deliverance to carps (Cyprinus carpio). Extracellular products (ECPs) of Aeromonas hydrophila as microbial antigen was efficiently loaded to form OCMCS-ECPs nanoparticles and shown to be sustained release in PBS. Significantly higher (P < 0.05) antigen-specific antibodies were detected in serum after orally immunized with OCMCS-ECPs nanoparticles than that immunized with ECPs alone and non-immunized in control group in carps. These results implied that amphiphilic modified chitosan nanoparticles had great potential to be applied as carriers for the oral administration of protein drugs.
Journal of Materials Science Materials in Medicine 12/2011; 23(2):375-84. · 2.32 Impact Factor
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ABSTRACT: Owing to its high biodegradability, and nontoxicity and antimicrobial properties, chitosan is widely-used as an antimicrobial agent either alone or blended with other natural polymers. To broaden chitosan's antimicrobial applicability, comprehensive knowledge of its activity is necessary. The paper reviews the current trend of investigation on antimicrobial activities of chitosan and its mode of action. Chitosan-mediated inhibition is affected by several factors can be classified into four types as intrinsic, environmental, microorganism and physical state, according to their respective roles. In this review, different physical states are comparatively discussed. Mode of antimicrobial action is discussed in parts of the active compound (chitosan) and the target (microorganisms) collectively and independently in same complex. Finally, the general antimicrobial applications of chitosan and perspectives about future studies in this field are considered.
International journal of food microbiology 10/2010; 144(1):51-63. · 3.01 Impact Factor
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08/2010: pages 307 - 332; , ISBN: 9780470669532
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ABSTRACT: Acetylated chitosan sponges (chitin sponges) were prepared according to acetylation time (25, 50, 75, and 100 h). As the acetylation time increased, the degree of acetylation increased, and a 75-h acetylation time produced the highest degree of acetylation (DA). The surface morphologies of samples were examined by scanning electron microscopy. Sponge samples were shown by a water uptake ability test to have higher water absorption abilities. An in vitro biodegradation test showed that sponges with a higher DA were more susceptible to lysozyme hydrolysis. Acetylated chitosan sponges were further shown by an in vitro fibroblast proliferation test to have a higher degree of cell viability on increasing the DA, with 75 h exhibiting the maximum effect. The results showed that the wound healing effect of chitosan sponges can be controlled by the DA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Journal of Applied Polymer Science 03/2010; 117(3):1618 - 1623. · 1.29 Impact Factor
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ABSTRACT: Chitosan-coated nano-size liposomes as a new carrier with bioactivity were made from phosphatidylcholine (pc) and cholesterol (chol) by direct injection. Liposomes prepared using ethanol as a solvent with pc:chol ratios of 40:60 and 60:40 displayed mall mean diameters (97.4nm and 95.8nm, respectively). Different factors affecting the loading efficiency and payload of Vitamin C for these nano-size liposomes were investigated by high-pressure liquid chromatography. Liposomes prepared with a pc:chol ratio of 60:40 were promising Vitamin C carriers with a maximum loading efficiency about 96.5% and payload about 46.82%. When liposomes were prepared with 100mg initial mass of Vitamin C, maximum loading efficiency was obtained. Furthermore, with an increasing initial mass of Vitamin C, the payload increased. Based on the experimental results, it appears that the chitosan concentration does not affect the loading efficiency and payload of liposomes. Liposomes prepared under the above optimum conditions were stable during 15 weeks storage such that over 85% Vitamin C was protected against oxidation.
Colloids and surfaces. B, Biointerfaces 10/2009; 76(1):16-9. · 2.60 Impact Factor
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ABSTRACT: A novel chitosan antibacterial dispersion system was prepared by oleoyl-chitosan (OCS) nanoparticles (OCNP). We further investigated the antimicrobial mode of OCNP against Escherichia coli and Staphylococcus aureus using a combination of approaches, including measurement of the effect of lecithin and phosphate groups, the conformation of membrane protein, internalization of fluorescein isothiocyanate (FITC)-labeled OCS nanoparticles (FITC-OCS nanoparticles) observed under fluorescence microscopy and DNA/RNA binding assay. Results of fluorescence experiments indicated that OCNP influenced the structure of bacterial membranes. The lecithin effect showed that OCNP bound to cytoplasmic membrane phospholipids of S. aureus, and phosphate groups played an important role. Fluorescence microscopy observations demonstrated that the way OCNP entered into bacteria varied against strains. The gel-retardation experiment showed that OCNP bound strongly to DNA/RNA and retarded their migration in the gels in a concentration-dependent manner. These results indicate that OCNP exerts its antibacterial activity by damaging the structures of cell membrane and putative binding to extracellular targets such as phosphate groups or intracellular targets such as DNA and RNA.
International journal of food microbiology 05/2009; 132(2-3):127-33. · 3.01 Impact Factor
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ABSTRACT: A new nutraceutical carrier, chitosan-coated nano-size liposome, which is itself bioactive, is made from phosphatidylcholine (pc) and cholesterol by the sonication method. Different factors related to the size of the liposomes such as the ratio of the pc and cholesterol and the time of sonication are investigated. At the 40 : 60 ratios of pc and cholesterol with 12 min sonication, the smallest liposomes, with mean diameter ∼82 nm, were obtained. Incorporation of chemically labile active ingredients into the chitosan-coated liposomes prevented chemical degradation, which is shown for vitamin E (VE). After VE was loaded to the liposomes, the size of chitosan-coated liposomes increased to 144 nm. The loading efficiency and payload of VE were investigated by loading different amounts of VE to the liposomes which were prepared with different ratios of pc and cholesterol. Chitosan-coated nano-coated nano-size liposomes appeared to be promising VE carriers, with highest loading efficiency over 99% and payload over 27%. The stability of VE-loaded liposomes suspension during the 8 weeks storage is over 90% under 4°C.
Journal of Microencapsulation 10/2008; 26(3):235-42. · 1.55 Impact Factor
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ABSTRACT: Lactobacillus casei ATCC 393-loaded microcapsules based on alginate and gelatin had been prepared by extrusion method and the product could increase the cell numbers of L. casei ATCC 393 to be 10(7) CFU g(-1) in the dry state of microcapsules. The microparticles homogeneously distributed with size of 1.1 ± 0.2 mm. Four kinds of microcapsules (S(1), S(2), S(3) and S(4)) exhibited swelling in simulated gastric fluid (SGF) while the beads eroded and disintegrated rapidly in simulated intestinal fluid (SIF). Cells of L. casei ATCC 393 could be continuously released from the microcapsules during simulated gastrointestinal tract (GIT) and the release amounts and speeds in SIF were much higher and faster than that in SGF. Encapsulation in alginate-gelatin microcapsules successfully improved the survival of L. casei ATCC 393 and this approach might be useful in delivery of probiotic cultures as a functional food.
Journal of Microencapsulation 09/2008; 26(4):315-24. · 1.55 Impact Factor
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ABSTRACT: A new method was developed for the determination of epichlorohydrin (ECH) in food contact surface of epoxy-coated cans. The oxolane derivative, which produced by reaction of epoxy moiety in ECH with cyclopentanone in the presence of borontrifluoride-diethyletherate, was analyzed by gas chromatography (GC)/mass spectrometry (MS). 1,2-Epoxyhexane was used as internal standard (IS), which produced an oxolane derivative under the same reaction mechanism as ECH. The developed method was validated with 1 ng ml(-1) of limit of detection (LOD, surface area related 20 ng dm(-2)), >0.999 of linearity. Good precision, which was tested both in terms of intra-day repeatability and inter-day reproducibility, and 97.3-102.7% of good recoveries were obtained on three spiked levels of 5.2, 40.3 and 149.1 ng ml(-1). The excellent validation data suggests that this method is more simple, quick and effective than the official method in European Committee for Standardization (CEN) to determine the residual amount of ECH in food contact materials for food law compliance test. The residual amount of ECH for 13 epoxy-coated can samples was analyzed, and none of the samples was found to be detectable levels of ECH in epoxy-coated cans.
Journal of Chromatography 08/2008; 1201(1):100-5. · 4.53 Impact Factor
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ABSTRACT: In this study, we investigated the interface contacting inhibition behaviors of chitosan against bacterial in the dispersing
state. For that purpose, chitosan microspheres (CMs) in the dispersing state was prepared by the emulsification cross-linking
method. The CMs had smooth surface and spherical shape with the diameter of about 124 µm. They were stable after sterilization
at 121°C and 150 kPa for 20 min. The CMs had similar antibacterial activity to that of chitosan in the solution form. Their
antibacterial activities increased with the increase of the CM concentration, while decreased with the increase of pH of the
system. It was found that the CMs with the degree of deacetylation (DD) of 63.6% exhibited the highest antibacterial activity,
while the CMs with the DD of 83.7% exerted the lowest antibacterial activity among the three tested samples.
Frontiers of Materials Science in China 01/2008; 2(2):214-220.
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ABSTRACT: Oleoylchitosans (O-chitosans), with different molecular masses and degrees of substitution (DS), were synthesized by reacting chitosan with oleoyl chloride. The FT-IR suggested the formation of an amide linkage between amino groups of chitosan and carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase was stronger as the increase of hydrophobicity (DS) and molecular mass of the polymer. The critical aggregation concentration (CAC) of O-chitosans with DS 5, 11, and 27% were 79.43, 31.6, 10 mg/L, respectively, and the CAC of samples with molecular masses of 20, 38, 300, and 1100 kDa were 50.1, 74.93, 125.9, and 630.9 mg/L, respectively. All of the O-chitosans could reduce surface tension slightly. Nanoparticles were prepared using an O/W emulsification method. Mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5 and 11% were around 327.4 and 275.3 nm, respectively.
Journal of Agricultural and Food Chemistry 07/2007; 55(12):4842-7. · 2.82 Impact Factor
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ABSTRACT: Different molecular weight (MW) chitosans (5.5×104 to 15.5×104 Da) with the same degree of deacetylation (80%±0.29), were obtained by the method of acetic acid hydrolysis. The effect of antimicrobial activities of chitosan and acetic acid against Escherichia coli were investigated. All of the chitosan samples with MW from 5.5×104 to 15.5×104 Da had antimicrobial activities at the concentrations higher than 200 ppm. The growth of E. coli was promoted at concentration lower than 200 ppm. The antibacterial activity of chitosan had relationship to the MW at the concentration range from 50 to 100 ppm. The antibacterial activity of low MW chitosan is higher than that of the high MW samples. But the chitosan sample with the middle MW (9.0×104 Da) could promote the growth of bacteria. In the different stages of cultivation, the earlier chitosan was added the greater effect it did. And the mechanism of antibacterial activity was that E. coli was flocculated.
Carbohydrate Polymers. 02/2006;
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ABSTRACT: The present study reports on the preparation of chitosan–tripolyphosphate (TPP) microspheres by the spray-drying method using acetaminophen as a model drug substance. Chitosan–TPP microspheres were spherical and had a smooth surface. Perfectly spherical chitosan–TPP microparticles loaded with acetaminophen were obtained in the size range of 3.1–10.1 µm. Spray-dried chitosan–TPP microspheres were positively charged (zeta potential ranged from +18.4 to +31.8). The encapsulation efficiency of these microspheres was in the range of 48.9–99.5%. The swelling capacity of chitosan–TPP microspheres increased with increases in the molecular weight of chitosan and decreases with increasing volume of 1% wt/vol TPP solution used for the cross-linking reaction. The effect of chitosan concentration, drug loading, volume of TPP solution used for cross-linking, and chitosan molecular weight on surface morphology and drug release rate was extensively investigated. Microparticles with spherical shape and slower release rates were obtained from chitosan–TPP microspheres prepared using a higher concentration of chitosan, higher volume of TPP solution, a higher molecular weight chitosan and/or a higher drug loading. Most importantly, the drug release rate was mainly controlled by the chitosan–TPP matrix density and, thus, by the degree of swelling of the hydrogel matrix. Drug release from chitosan–TPP microspheres occurred via diffusion as the best fit for drug release was obtained using the Higuchi equation. Drug Dev. Res. 64:114–128, 2005. © 2005 Wiley-Liss, Inc.
Drug Development Research 05/2005; 64(2):114 - 128. · 1.19 Impact Factor
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ABSTRACT: Trypsin was immobilized on linolenic acid modified chitosan using glutaraldehyde (GA) as cross-linker, which was confirmed by Fourier transform infrared (FTIR) spectra. The chitosan nanoparticles containing trypsin (TR) can be prepared after the sonication of immobilized trypsin. The GA concentration affected both the enzyme activity of the nanoparticle and particle size. Results indicated that the activity of trypsin immobilized onto linolenic acid modified chitosan nanoparticles increased with increasing concentration of GA up to 0.07% (v/v) and then decreased with increasing amount of GA. On the other hand, particle size increased (from 523 to 1372 nm) with the increasing concentration of GA (from 0.03 to 0.1% v/v). The enzyme catalytic characteristics of nanoparticle solution were also studied. The results showed that the kinetic constant value (K(m)) of TR immobilized on nanoparticle (71.9 mg/mL) was higher than that of pure TR (50.2 mg/mL). However, the thermal stability and optimum temperature of TR immobilized on nanoparticles improved, which make it more attractive in the application aspect.
Journal of Agricultural and Food Chemistry 04/2005; 53(5):1728-33. · 2.82 Impact Factor
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ABSTRACT: Chitosan was modified by coupling with linolenic acid through the 1-ethyl-3-(3-dimethylaminopropyyl)carbodiimide-mediated reaction. The degree of substitution was measured by 1H NMR, and it was 1.8%, i.e., 1.8 linolenic acids group per 100 anhydroglucose units. The critical aggregation concentration (CAC) of the self-aggregate of hydrophobically modified chitosan was determined by measuring the fluorescence intensity of the pyrene as a fluorescent probe. The CAC value in phosphate-buffered saline (PBS) solution (pH 7.4) was 5 x 10(-2) mg/mL. The average particle size of self-aggregates of hydrophobically modified chitosan in PBS solution (pH 7.4) was 210.8 nm with a unimodal size distribution ranging from 100 to 500 nm. A transmission electron microscopy study showed that the formation of near spherical shape nanoparticles had enough structural integrity. The loading ability of hydrophobically modified chitosan (LA-chitosan) was investigated by using bovine serum albumin (BSA) as a model protein. Self-aggregated nanoparticles exhibited an increased loading capacity (19.85 +/- 0.04 to 37.57 +/- 0.25%) with an increasing concentration of BSA (0.1-0.5 mg/mL).
Journal of Agricultural and Food Chemistry 02/2005; 53(2):437-41. · 2.82 Impact Factor
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ABSTRACT: The aqueous solution of alginate was irradiated by 60Co gamma-rays in the dose range of 10-500 kGy. To assess the effect of irradiation on the degradation of alginate, the irradiation-induced changes in the viscosity, molecular weight, color, monomer composition, and sequence were measured. The molecular weight of raw alginate was reduced from 300000 to 25000 when irradiated at 100 kGy. The degradation rate decreased and the chain breaks per molecule increased with increasing irradiation dose. The viscosity of irradiated alginate solution reached a near minimum as low as at 10 kGy. No appreciable color changes were observed in the samples irradiated at up to 100 kGy, but intense browning occurred beyond 200 kGy. The 13C NMR spectra showed that homopolymeric blocks, MM and GG, increased and the M/G ratio decreased with irradiation. Considering both the level of degradation and the color change of alginate, the optimum irradiation dose was found to be 100 kGy.
Journal of Agricultural and Food Chemistry 08/2003; 51(16):4819-23. · 2.82 Impact Factor
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ABSTRACT: Chitosan was modified by coupling with linoleic acid through the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-mediated reaction to increase its amphipathicity for improved emulsification. The micelle formation of linoleic acid-modified chitosan in the 0.1 M acetic acid solution was enhanced by O/W emulsification with methylene chloride, an oil phase. The fluorescence spectra indicate that without emulsification the self-aggregation of LA-chitosan occurred at the concentration of 1.0 g/L or above, and with emulsification, self-aggregation was greatly enhanced followed by a stable micelle formation at 2.0 g/L. The addition of 1 M sodium chloride promoted the self-aggregation of LA-chitosan molecules both with and without emulsification. The micelles of LA-chitosan formed nanosize particles ranging from 200 to 600 nm. The LA-chitosan nanoparticles encapsulated the lipid soluble model compound, retinal acetate, with 50% efficiency.
Journal of Agricultural and Food Chemistry 06/2003; 51(10):3135-9. · 2.82 Impact Factor
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ABSTRACT: In this study, different molecular weight CM-chitosans were prepared and the effects on the growth and collagen secretion of normal skin fibroblasts and keloid fibroblasts were investigated in vitro. CM-chitosan promoted the proliferation of the normal skin fibroblast significantly but inhibited the proliferation of keloid fibroblast. The higher CM-chitosan concentration had a higher initial effect and the lower CM-chitosan concentration had a longer affecting time to the normal skin fibroblast. The lower molecular weight CM-chitosan had significant twofold activities. The CM-chitosan could reduce the ratio of type I/III collagen in keloid fibroblast by inhibiting the secretion of collagen type I; and had no effect on the secretion of types I and III collagen in the normal skin fibroblast.
Biomaterials 01/2003; 23(23):4609-14. · 7.40 Impact Factor
