Research

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Open AccessArticle

Natural-Synthetic Hybrid Polymers Developed via Electrospinning: The Effect of PET in Chitosan/Starch System

by

Adolfo Espíndola-González

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Ana Laura Martínez-Hernández

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Francisco Fernández-Escobar

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Victor Manuel Castaño

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Witold Brostow

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Tea Datashvili

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Carlos Velasco-Santos

Int. J. Mol. Sci. 2011, 12(3), 1908-1920; https://doi.org/10.3390/ijms12031908 - 16 Mar 2011

Cited by 36 | Viewed by 10938

Abstract

Chitosan is an amino polysaccharide found in nature, which is biodegradable, nontoxic and biocompatible. It has versatile features and can be used in a variety of applications including films, packaging, and also in medical surgery. Recently a possibility to diversify chitosan properties has [...] Read more.

Chitosan is an amino polysaccharide found in nature, which is biodegradable, nontoxic and biocompatible. It has versatile features and can be used in a variety of applications including films, packaging, and also in medical surgery. Recently a possibility to diversify chitosan properties has emerged by combining it with synthetic materials to produce novel natural-synthetic hybrid polymers. We have studied structural and thermophysical properties of chitosan + starch + poly(ethylene terephthalate) (Ch + S + PET) fibers developed via electrospinning. Properties of these hybrids polymers are compared with extant chitosan containing hybrids synthesized by electrospinning. Molecular interactions and orientation in the fibers are analyzed by infrared and Raman spectroscopies respectively, morphology by scanning electron microscopy and thermophysical properties by thermogravimetric analysis and differential scanning calorimetry. Addition of PET to Ch + S systems results in improved thermal stability at elevated temperatures. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

N-Acetyl Glucosamine Obtained from Chitin by Chitin Degrading Factors in Chitinbacter tainanesis

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Int. J. Mol. Sci. 2011, 12(2), 1187-1195; https://doi.org/10.3390/ijms12021187 - 17 Feb 2011

Cited by 28 | Viewed by 8993

Abstract

A novel chitin-degrading aerobe, Chitinibacter tainanensis, was isolated from a soil sample from southern Taiwan, and was proved to produce N-acetyl glucosamine (NAG). Chitin degrading factors (CDFs) were proposed to be the critical factors to degrade chitin in this work. When [...] Read more.

A novel chitin-degrading aerobe, Chitinibacter tainanensis, was isolated from a soil sample from southern Taiwan, and was proved to produce N-acetyl glucosamine (NAG). Chitin degrading factors (CDFs) were proposed to be the critical factors to degrade chitin in this work. When C. tainanensis was incubated with chitin, CDFs were induced and chitin was converted to NAG. CDFs were found to be located on the surface of C. tainanensis. N-Acetylglucosaminidase (NAGase) and endochitinase activities were found in the debris, and the activity of NAGase was much higher than that of endochitinase. The optimum pH of the enzymatic activity was about 7.0, while that of NAG production by the debris was 5.3. These results suggested that some factors in the debris, in addition to NAGase and endochitinase, were crucial for chitin degradation. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

Development of a Chitosan-Based Biofoam: Application to the Processing of a Porous Ceramic Material

by

Jean-Denis Mathias

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Nicolas Tessier-Doyen

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Philippe Michaud

Int. J. Mol. Sci. 2011, 12(2), 1175-1186; https://doi.org/10.3390/ijms12021175 - 16 Feb 2011

Cited by 14 | Viewed by 11154

Abstract

Developing biofoams constitutes a challenging issue for several applications. The present study focuses on the development of a chitosan-based biofoam. Solutions of chitosan in acetic acid were dried under vacuum to generate foams with high-order structures. Chitosan concentration influenced significantly the morphology of [...] Read more.

Developing biofoams constitutes a challenging issue for several applications. The present study focuses on the development of a chitosan-based biofoam. Solutions of chitosan in acetic acid were dried under vacuum to generate foams with high-order structures. Chitosan concentration influenced significantly the morphology of developed porosity and the organization of pores in the material. Physico-chemical characterizations were performed to investigate the effects of chitosan concentration on density and thermal conductivity of foams. Even if chitosan-based biofoams exhibit interesting insulating properties (typically around 0.06 W·m⁻¹·K⁻¹), it has been shown that their durabilities are limited when submitted to a wet media. So, a way of application consists to elaborate a ceramic material with open porosity from a slurry prepared with an organic solvent infiltrating the porous network of the foam. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

Effectiveness of Chitosan against Mature Biofilms Formed by Food Related Bacteria

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Int. J. Mol. Sci. 2011, 12(1), 817-828; https://doi.org/10.3390/ijms12010817 - 21 Jan 2011

Cited by 91 | Viewed by 12241

Abstract

Chitosan has proven antimicrobial properties against planktonic cell growth. Little is known, however, about its effects on already established biofilms. Oriented for application in food industry disinfection, the effectiveness of both medium molecular weight (MMW) chitosan and its enzymatically hydrolyzed product was tested [...] Read more.

Chitosan has proven antimicrobial properties against planktonic cell growth. Little is known, however, about its effects on already established biofilms. Oriented for application in food industry disinfection, the effectiveness of both medium molecular weight (MMW) chitosan and its enzymatically hydrolyzed product was tested against mature biofilms of four pathogenic strains, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus and Salmonella enterica, and a food spoilage species, Pseudomonas fluorescens. Unexpectedly, log reductions were in some cases higher for biofilm than for planktonic cells. One hour exposure to MMW chitosan (1% w/v) caused a 6 log viable cell reduction on L. monocytogenes monospecies mature biofilms and reduced significantly (3–5 log reductions) the attached population of the other organisms tested, except S. aureus. Pronase-treated chitosan was more effective than MMW chitosan on all tested microorganisms, also with the exception of S. aureus, offering best results (8 log units) against the attached cells of B. cereus. These treatments open a new possibility to fight against mature biofilms in the food industry. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

Effects of the Molecular Weight and the Degree of Deacetylation of Chitosan Oligosaccharides on Antitumor Activity

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Int. J. Mol. Sci. 2011, 12(1), 266-277; https://doi.org/10.3390/ijms12010266 - 06 Jan 2011

Cited by 153 | Viewed by 11725

Abstract

Effects of the degree of deacetylation (DDA) and the molecular mass of chitosan oligosaccharides (CTS-OS), obtained from the enzymatic hydrolysis of high molecular weight chitosan (HMWC), on antitumor activity was explored. The DDA and molecular weights of CTS-OS were determined by matrix-assisted laser [...] Read more.

Effects of the degree of deacetylation (DDA) and the molecular mass of chitosan oligosaccharides (CTS-OS), obtained from the enzymatic hydrolysis of high molecular weight chitosan (HMWC), on antitumor activity was explored. The DDA and molecular weights of CTS-OS were determined by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-TOF MS) analysis. The CTS-OS were found to be a mixture of mainly dimers (18.8%), trimers (24.8%), tetramers (24.9%), pentamers (17.7%), hexamers (7.1%), heptamers (3.3%), and octamers (3.4%). The CTS-OS were further fractionated by gel-filtration chromatography into two major fractions: (1) COS, consisting of glucosamine (GlcN)_n, n = 3–5 with DDA 100%; and (2) HOS, consisting of (GlcN)₅ as the minimum residues and varying number of N-acetylglucosamine (GlcNAc)_n, n = 1–2 with DDA about 87.5% in random order. The cytotoxicities, expressed as the concentration needed for 50% cell death (CC₅₀), of CTS-OS, COS, and HOS against PC3 (prostate cancer cell), A549 (lung cancer cell), and HepG2 (hepatoma cell), were determined to be 25 mg∙mL^-1, 25 mg∙mL^-1, and 50 mg∙mL^-1, respectively. The HMWC was approximately 50% less effective than both CTS-OS and COS. These results demonstrate that the molecular weight and DDA of chitosan oligosaccharides are important factors for suppressing cancer cell growth. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

The Chitinolytic Activities of Streptomyces sp. TH-11

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and Chun-Yi Liau

Int. J. Mol. Sci. 2011, 12(1), 56-65; https://doi.org/10.3390/ijms12010056 - 27 Dec 2010

Cited by 24 | Viewed by 11203

Abstract

Chitin is an abundant biopolymer composed of units of N-acetyl-D-glucosamine linked by b-1,4 glycosidic bonds. Chitin is the main component of the shells of mollusks, the cell wall of fungi and yeast and of the exoskeleton of crustaceans and insects. The degradation [...] Read more.

Chitin is an abundant biopolymer composed of units of N-acetyl-D-glucosamine linked by b-1,4 glycosidic bonds. Chitin is the main component of the shells of mollusks, the cell wall of fungi and yeast and of the exoskeleton of crustaceans and insects. The degradation of chitin is catalyzed by chitinases that occur in a wide range of organisms. Among them, the chitinases from microorganisms are extremely important for the degradation and recycling of the carbon and nitrogen trapped in the large amount of insoluble chitin in nature. Streptomyces sp. TH-11 was isolated from the sediment of the Tou-Chien River, Taiwan. The chitinolytic enzyme activities were detected using a rapid in-gel detection method from the cell-free preparation of the culture medium of TH-11. The chitinolytic enzyme activity during prolonged liquid culturing was also analyzed by direct measurement of the chitin consumption. Decomposition of the exoskeleton of shrimps was demonstrated using electron microscopy and atomic force microscopy. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

In Vivo Biocompatibility Study of Electrospun Chitosan Microfiber for Tissue Engineering

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Int. J. Mol. Sci. 2010, 11(10), 4140-4148; https://doi.org/10.3390/ijms11104140 - 25 Oct 2010

Cited by 31 | Viewed by 11341

Abstract

In this work, we examined the biocompatibility of electrospun chitosan microfibers as a scaffold. The chitosan microfibers showed a three-dimensional pore structure by SEM. The chitosan microfibers supported attachment and viability of rat muscle-derived stem cells (rMDSCs). Subcutaneous implantation of the chitosan microfibers [...] Read more.

In this work, we examined the biocompatibility of electrospun chitosan microfibers as a scaffold. The chitosan microfibers showed a three-dimensional pore structure by SEM. The chitosan microfibers supported attachment and viability of rat muscle-derived stem cells (rMDSCs). Subcutaneous implantation of the chitosan microfibers demonstrated that implantation of rMDSCs containing chitosan microfibers induced lower host tissue responses with decreased macrophage accumulation than did the chitosan microfibers alone, probably due to the immunosuppression of the transplanted rMDSCs. Our results collectively show that chitosan microfibers could serve as a biocompatible in vivo scaffold for rMDSCs in rats. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

Fabrication of Chitosan/Silk Fibroin Composite Nanofibers for Wound-dressing Applications

by

Zeng-xiao Cai

,

Xiu-mei Mo

, Kui-hua Zhang, Lin-peng Fan, An-lin Yin, Chuang-long He and Hong-sheng Wang

Int. J. Mol. Sci. 2010, 11(9), 3529-3539; https://doi.org/10.3390/ijms11093529 - 21 Sep 2010

Cited by 284 | Viewed by 18413

Abstract

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin [...] Read more.

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

A Selective Assay to Detect Chitin and Biologically Active Nano-Machineries for Chitin-Biosynthesis with Their Intrinsic Chitin-Synthase Molecules

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Int. J. Mol. Sci. 2010, 11(9), 3122-3137; https://doi.org/10.3390/ijms11093122 - 07 Sep 2010

Cited by 5 | Viewed by 9190

Abstract

A new assay system for chitin has been developed. It comprises the chitin-binding protein ChbB in fusion with a His-tag as well as with a Strep-tag, the latter of which was chemically coupled to horseradish peroxidase. With the resulting complex, minimal quantities of [...] Read more.

A new assay system for chitin has been developed. It comprises the chitin-binding protein ChbB in fusion with a His-tag as well as with a Strep-tag, the latter of which was chemically coupled to horseradish peroxidase. With the resulting complex, minimal quantities of chitin are photometrically detectable. In addition, the assay allows rapid scoring of the activity of chitin-synthases. As a result, a refined procedure for the rapid purification of yeast chitosomes (nano-machineries for chitin biosynthesis) has been established. Immuno-electronmicroscopical studies of purified chitosomes, gained from a yeast strain carrying a chitin-synthase gene fused to that for GFP (green-fluorescence protein), has led to the in situ localization of chitin-synthase-GFP molecules within chitosomes. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessArticle

Temperature Shifts for Extraction and Purification of Zygomycetes Chitosan with Dilute Sulfuric Acid

by

Akram Zamani

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Lars Edebo

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Claes Niklasson

and

Mohammad J. Taherzadeh

Int. J. Mol. Sci. 2010, 11(8), 2976-2987; https://doi.org/10.3390/ijms11082976 - 13 Aug 2010

Cited by 29 | Viewed by 10428

Abstract

The temperature-dependent hydrolysis and solubility of chitosan in sulfuric acid solutions offer the possibility for chitosan extraction from zygomycetes mycelia and separation from other cellular ingredients with high purity and high recovery. In this study, Rhizomucor pusillus biomass was initially extracted with 0.5 [...] Read more.

The temperature-dependent hydrolysis and solubility of chitosan in sulfuric acid solutions offer the possibility for chitosan extraction from zygomycetes mycelia and separation from other cellular ingredients with high purity and high recovery. In this study, Rhizomucor pusillus biomass was initially extracted with 0.5 M NaOH at 120 °C for 20 min, leaving an alkali insoluble material (AIM) rich in chitosan. Then, the AIM was subjected to two steps treatment with 72 mM sulfuric acid at (i) room temperature for 10 min followed by (ii) 120 °C for 45 min. During the first step, phosphate of the AIM was released into the acid solution and separated from the chitosan-rich residue by centrifugation. In the second step, the residual AIM was re-suspended in fresh 72 mM sulfuric acid, heated at 120 °C and hot filtered, whereby chitosan was extracted and separated from the hot alkali and acid insoluble material (HAAIM). The chitosan was recovered from the acid solution by precipitation at lowered temperature and raised pH to 8-10. The treatment resulted in 0.34 g chitosan and 0.16 g HAAIM from each gram AIM. At the start, the AIM contained at least 17% phosphate, whereas after the purification, the corresponding phosphate content of the obtained chitosan was just 1%. The purity of this chitosan was higher than 83%. The AIM subjected directly to the treatment with hot sulfuric acid (at 120 °C for 45 min) resulted in a chitosan with a phosphate impurity of 18.5%. Full article

(This article belongs to the Special Issue Chitins)

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Open AccessReview

Chitin Scaffolds in Tissue Engineering

by

Rangasamy Jayakumar

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Krishna Prasad Chennazhi

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Int. J. Mol. Sci. 2011, 12(3), 1876-1887; https://doi.org/10.3390/ijms12031876 - 15 Mar 2011

Cited by 149 | Viewed by 12962

Abstract

Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by [...] Read more.

Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. Full article

(This article belongs to the Special Issue Chitins)

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