International Journal of Molecular Sciences

Research

Jump to: Review

5805 KiB

Open AccessArticle

Neuropeptide Substance-P-Conjugated Chitosan Nanofibers as an Active Modulator of Stem Cell Recruiting

by Min Sup Kim, Sang Jun Park, Wheemoon Cho, Bon Kang Gu and Chun-Ho Kim

Int. J. Mol. Sci. 2016, 17(1), 68; https://doi.org/10.3390/ijms17010068 - 7 Jan 2016

Cited by 10 | Viewed by 5575

Abstract

The goal to successful wound healing is essentially to immobilize and recruit appropriate numbers of host stem or progenitor cells to the wound area. In this study, we developed a chitosan nanofiber-immobilized neuropeptide substance-P (SP), which mediates stem cell mobilization and migration, onto [...] Read more.

The goal to successful wound healing is essentially to immobilize and recruit appropriate numbers of host stem or progenitor cells to the wound area. In this study, we developed a chitosan nanofiber-immobilized neuropeptide substance-P (SP), which mediates stem cell mobilization and migration, onto the surfaces of nanofibers using a peptide-coupling agent, and evaluated its biological effects on stem cells. The amount of immobilized SP on chitosan nanofibers was modulated over the range of 5.89 ± 3.27 to 75.29 ± 24.31 ng when reacted with 10 to 500 ng SP. In vitro migration assays showed that SP-incorporated nanofibers induced more rapid migration of human mesenchymal stem cells on nanofibers compared to pristine samples. Finally, the conjugated SP evoked a minimal foreign body reaction and recruited a larger number of CD29- and CD44-positive stem cells into nanofibers in a mouse subcutaneous pocket model. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

3481 KiB

Open AccessArticle

Development and Characterization of Novel Films Based on Sulfonamide-Chitosan Derivatives for Potential Wound Dressing

by Oana Maria Dragostin, Sangram Keshari Samal, Florentina Lupascu, Andreea Pânzariu, Peter Dubruel, Dan Lupascu, Cristina Tuchilus, Cornelia Vasile and Lenuta Profire

Int. J. Mol. Sci. 2015, 16(12), 29843-29855; https://doi.org/10.3390/ijms161226204 - 15 Dec 2015

Cited by 18 | Viewed by 6569

Abstract

The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol) in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well [...] Read more.

The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol) in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well the antioxidant effects of sulfonamide-chitosan derivatives were investigated. The chitosan-derivative films showed a rough surface and hydrophilic properties, which are very important features for their use as a wound dressing. The film based on chitosan-sulfisoxazol (CS-S6) showed the highest swelling ratio (197%) and the highest biodegradation rate (63.04%) in comparison to chitosan film for which the swelling ratio was 190% and biodegradation rate was only 10%. Referring to the antioxidant effects the most active was chitosan-sulfamerazine (CS-S5) which was 8.3 times more active than chitosan related to DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging ability. This compound showed also a good ferric reducing power and improved total antioxidant capacity. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

1750 KiB

Open AccessArticle

Preparation of a Near-Infrared Ray Absorption Film from N-Phenylthiocarbamoyl Chitosan Derivative

by Shouko Nishida, Masaya Shibano, Hiroshi Kamitakahara and Toshiyuki Takano

Int. J. Mol. Sci. 2015, 16(12), 29093-29102; https://doi.org/10.3390/ijms161226153 - 4 Dec 2015

Cited by 1 | Viewed by 5381

Abstract

We recently observed that the decanoylation of N-phenylthiocarbamoyl chitosan (2) with a mixture of decanoic anhydride and pyridine at 60 °C for 24 h afforded N,N-(decanoyl)phenythiocarbamoyl-/2-isothiocynato chitosan decanoate (3b) rather than the expected product N [...] Read more.

We recently observed that the decanoylation of N-phenylthiocarbamoyl chitosan (2) with a mixture of decanoic anhydride and pyridine at 60 °C for 24 h afforded N,N-(decanoyl)phenythiocarbamoyl-/2-isothiocynato chitosan decanoate (3b) rather than the expected product N,N-(decanoyl)phenylthiocarbamoyl chitosan decanoate (3a). This result suggested that some of the N,N-(decanoyl)phenylthiocarmbamoyl groups had been converted to isothiocyanate groups during the decanoylation process. The subsequent reaction of compound 3b with aniline gave N,N-(decanoyl)phenylthiocarbamoyl/N-phenylthiocarbamoyl chitosan decanoate (4) in high yield. A solution of compound 4 in CHCl₃ was then added to a solution of copper decanoate (5) in the same solvent, and the resulting mixture was cast onto a glass plate to give a cast film. The film was annealed at 200 °C in an oven to give a greenish film, which showed good near-infrared absorption characteristic in the range of 800–2200 nm. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

1361 KiB

Open AccessArticle

The Correlation between Chitin and Acidic Mammalian Chitinase in Animal Models of Allergic Asthma

by Chia-Rui Shen, Horng-Heng Juang, Hui-Shan Chen, Ching-Jen Yang, Chia-Jen Wu, Meng-Hua Lee, Yih-Shiou Hwang, Ming-Ling Kuo, Ya-Shan Chen, Jeen-Kuan Chen and Chao-Lin Liu

Int. J. Mol. Sci. 2015, 16(11), 27371-27377; https://doi.org/10.3390/ijms161126033 - 16 Nov 2015

Cited by 18 | Viewed by 5357

Abstract

Asthma is the result of chronic inflammation of the airways which subsequently results in airway hyper-responsiveness and airflow obstruction. It has been shown that an elicited expression of acidic mammalian chitinase (AMCase) may be involved in the pathogenesis of asthma. Our recent study [...] Read more.

Asthma is the result of chronic inflammation of the airways which subsequently results in airway hyper-responsiveness and airflow obstruction. It has been shown that an elicited expression of acidic mammalian chitinase (AMCase) may be involved in the pathogenesis of asthma. Our recent study has demonstrated that the specific suppression of elevated AMCase leads to reduced eosinophilia and Th2-mediated immune responses in an ovalbumin (OVA)-sensitized mouse model of allergic asthma. In the current study, we show that the elicited expression of AMCase in the lung tissues of both ovalbumin- and Der P2-induced allergic asthma mouse models. The effects of allergic mediated molecules on AMCase expression were evaluated by utilizing promoter assay in the lung cells. In fact, the exposure of chitin, a polymerized sugar and the fundamental component of the major allergen mite and several of the inflammatory mediators, showed significant enhancement on AMCase expression. Such obtained results contribute to the basis of developing a promising therapeutic strategy for asthma by silencing AMCase expression. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Figure 1

1511 KiB

Open AccessArticle

Characterization of Chitosan Nanofiber Sheets for Antifungal Application

by Mayumi Egusa, Ryo Iwamoto, Hironori Izawa, Minoru Morimoto, Hiroyuki Saimoto, Hironori Kaminaka and Shinsuke Ifuku

Int. J. Mol. Sci. 2015, 16(11), 26202-26210; https://doi.org/10.3390/ijms161125947 - 2 Nov 2015

Cited by 21 | Viewed by 7655

Abstract

Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of [...] Read more.

Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth inhibition against dermatophytes Microsporum and Trichophyton. Moreover, the chitosan NF sheets exhibited resistance to degradation by the fungi, suggesting potentials long-lasting usage. In addition, surface-deacetylated chitin nanofiber (SDCNF) sheets were prepared. The SDCNF sheet had a high Young’s modulus and tensile strength and showed antifungal activity to dermatophytes. These data indicate that nanofibrillation improved the properties of chitosan. Thus, chitosan NF and SDCNF sheets are useful candidates for antimicrobial materials. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Figure 1

1763 KiB

Open AccessArticle

Comparison of Simple Eudragit Microparticles Loaded with Prednisolone and Eudragit-Coated Chitosan-Succinyl-Prednisolone Conjugate Microparticles: Part II. In Vivo Evaluation of Efficacy, Toxicity, and Biodisposition Characteristics

by Hiraku Onishi and Hisashi Kikuchi

Int. J. Mol. Sci. 2015, 16(11), 26125-26136; https://doi.org/10.3390/ijms161125949 - 2 Nov 2015

Cited by 6 | Viewed by 5840

Abstract

We previously prepared and evaluated simple Eudragit S100 microparticles loaded with prednisolone (ES-MP) and Eudragit S100-coated chitosan-succinyl-prednisolone conjugate microparticles (Ch-MP/ES) in vitro. In this work, the effectiveness, toxic side effects (5 mg prednisolone (PD) eq/kg × 3 d, 10 mg PD eq/kg [...] Read more.

We previously prepared and evaluated simple Eudragit S100 microparticles loaded with prednisolone (ES-MP) and Eudragit S100-coated chitosan-succinyl-prednisolone conjugate microparticles (Ch-MP/ES) in vitro. In this work, the effectiveness, toxic side effects (5 mg prednisolone (PD) eq/kg × 3 d, 10 mg PD eq/kg × 3 d), and pharmacokinetic characteristics (5 mg PD eq/kg) were examined using rats with colitis induced through 2,4,6-trinitrobenzenesulfonic acid. ES-MP did not change the efficacy or toxic side effects of PD, and this was attributed to incomplete delivery to the target site and prolonged systemic drug absorption by ES-MP. On the other hand, Ch-MP/ES promoted the efficacy of PD and ameliorated its toxic side effects due to better delivery to the target site, very slow drug release and the strong suppression of drug absorption. Only Ch-MP/ES, which markedly changed drug release characteristics, improved the in vivo features of PD. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

1376 KiB

Open AccessArticle

Surface-Deacetylated Chitin Nano-Fiber/Hyaluronic Acid Composites as Potential Antioxidative Compounds for Use in Extended-Release Matrix Tablets

by Makoto Anraku, Ryo Tabuchi, Shinsuke Ifuku, Takako Ishiguro, Daisuke Iohara and Fumitoshi Hirayama

Int. J. Mol. Sci. 2015, 16(10), 24707-24717; https://doi.org/10.3390/ijms161024707 - 16 Oct 2015

Cited by 12 | Viewed by 6018

Abstract

In this study, we examined a possible use of a surface-deacetylated chitin nano-fiber (SDCH-NF) and hyaluronic acid (HA) interpolymer complex (IPC) tablet as a potential antioxidative compound in extended-release matrix tablets. The antioxidant properties of untreated chitin (UCH), SDCH-NF, and HA were examined [...] Read more.

In this study, we examined a possible use of a surface-deacetylated chitin nano-fiber (SDCH-NF) and hyaluronic acid (HA) interpolymer complex (IPC) tablet as a potential antioxidative compound in extended-release matrix tablets. The antioxidant properties of untreated chitin (UCH), SDCH-NF, and HA were examined using N-centered radicals derived from 1,1′-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). SDCH-NF and HA had acceptable scavenging abilities and were relatively efficient radical scavengers, but UCH was much less effective. The results suggest that SDCH-NF and HA could serve as scavengers of compounds related to the development of oxidative stress. An SDCH-NF/HA IPC tablet was prepared and evaluated as an extended-release tablet matrix using famotidine (FMT) as a model drug. The release of FMT from the IPC tablet (DCF-NF:HA = 1:1) was slower than that from a SDCH-NF only tablet. Turbidity measurements and X-ray diffraction (XRD) data also indicated that the optimum complexation ratio for IPC between SDCH-NF/HA is 1/1, resulting in a good relationship between turbidity or XRD of the complex and the release ratio of FMT. These results suggest that an SDCH-NF/HA tablet has the potential for use in an extended-release IPC tablet with a high antioxidant activity. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

1456 KiB

Open AccessArticle

Effects of Oral Administration of Chitin Nanofiber on Plasma Metabolites and Gut Microorganisms

by Kazuo Azuma, Ryotaro Izumi, Mari Kawata, Tomone Nagae, Tomohiro Osaki, Yusuke Murahata, Takeshi Tsuka, Tomohiro Imagawa, Norihiko Ito, Yoshiharu Okamoto, Minoru Morimoto, Hironori Izawa, Hiroyuki Saimoto and Shinsuke Ifuku

Int. J. Mol. Sci. 2015, 16(9), 21931-21949; https://doi.org/10.3390/ijms160921931 - 10 Sep 2015

Cited by 15 | Viewed by 9316

Abstract

The aim of this study was to examine the effects of oral administration of chitin nanofibers (CNFs) and surface-deacetylated (SDA) CNFs on plasma metabolites using metabolome analysis. Furthermore, we determined the changes in gut microbiota and fecal organic acid concentrations following oral administrations [...] Read more.

The aim of this study was to examine the effects of oral administration of chitin nanofibers (CNFs) and surface-deacetylated (SDA) CNFs on plasma metabolites using metabolome analysis. Furthermore, we determined the changes in gut microbiota and fecal organic acid concentrations following oral administrations of CNFs and SDACNFs. Healthy female mice (six-week-old) were fed a normal diet and administered tap water with 0.1% (v/v) CNFs or SDACNFs for 28 days. Oral administration of CNFs increased plasma levels of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and serotonin (5-hydroxytryptamine, 5-HT). Oral administration of SDACNFs affected the metabolisms of acyl-carnitines and fatty acids. The fecal organic level analysis indicated that oral administration of CNFs stimulated and activated the functions of microbiota. These results indicate that oral administration of CNFs increases plasma levels of ATP and 5-HT via activation of gut microbiota. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

2165 KiB

Open AccessArticle

Synthesis and Characterization of Chitosan-Coated Near-Infrared (NIR) Layered Double Hydroxide-Indocyanine Green Nanocomposites for Potential Applications in Photodynamic Therapy

by Pei-Ru Wei, Yaswanth Kuthati, Ranjith Kumar Kankala and Chia-Hung Lee

Int. J. Mol. Sci. 2015, 16(9), 20943-20968; https://doi.org/10.3390/ijms160920943 - 1 Sep 2015

Cited by 40 | Viewed by 8585

Abstract

We designed a study for photodynamic therapy (PDT) using chitosan coated Mg–Al layered double hydroxide (LDH) nanoparticles as the delivery system. A Food and Drug Administration (FDA) approved near-infrared (NIR) fluorescent dye, indocyanine green (ICG) with photoactive properties was intercalated into amine modified [...] Read more.

We designed a study for photodynamic therapy (PDT) using chitosan coated Mg–Al layered double hydroxide (LDH) nanoparticles as the delivery system. A Food and Drug Administration (FDA) approved near-infrared (NIR) fluorescent dye, indocyanine green (ICG) with photoactive properties was intercalated into amine modified LDH interlayers by ion-exchange. The efficient positively charged polymer (chitosan (CS)) coating was achieved by the cross linkage using surface amine groups modified on the LDH nanoparticle surface with glutaraldehyde as a spacer. The unique hybridization of organic-inorganic nanocomposites rendered more effective and successful photodynamic therapy due to the photosensitizer stabilization in the interlayer of LDH, which prevents the leaching and metabolization of the photosensitizer in the physiological conditions. The results indicated that the polymer coating and the number of polymer coats have a significant impact on the photo-toxicity of the nano-composites. The double layer chitosan coated LDH–NH₂–ICG nanoparticles exhibited enhanced photo therapeutic effect compared with uncoated LDH–NH₂–ICG and single layer chitosan-coated LDH–NH₂–ICG due to the enhanced protection to photosensitizers against photo and thermal degradations. This new class of organic-inorganic hybrid nanocomposites can potentially serve as a platform for future non-invasive cancer diagnosis and therapy. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

650 KiB

Open AccessArticle

Effects of Surface-Deacetylated Chitin Nanofibers in an Experimental Model of Hypercholesterolemia

by Kazuo Azuma, Tomone Nagae, Takeshi Nagai, Hironori Izawa, Minoru Morimoto, Yusuke Murahata, Tomohiro Osaki, Takeshi Tsuka, Tomohiro Imagawa, Norihiko Ito, Yoshiharu Okamoto, Hiroyuki Saimoto and Shinsuke Ifuku

Int. J. Mol. Sci. 2015, 16(8), 17445-17455; https://doi.org/10.3390/ijms160817445 - 30 Jul 2015

Cited by 22 | Viewed by 6106

Abstract

This study evaluated the effects of oral administration of surface-deacetylated chitin nanofibers (SDACNFs) on hypercholesterolemia using an experimental model. All rats were fed a high cholesterol diet with 1% w/w cholesterol and 0.5% w/w cholic acid for 28 days. [...] Read more.

This study evaluated the effects of oral administration of surface-deacetylated chitin nanofibers (SDACNFs) on hypercholesterolemia using an experimental model. All rats were fed a high cholesterol diet with 1% w/w cholesterol and 0.5% w/w cholic acid for 28 days. Rats were divided equally into four groups: the control group was administered 0.05% acetic acid dissolved in tap water, and the SDACNF, chitosan (CS), and cellulose nanofiber (CLNF) groups were administered 0.1% CNF, CS, or CLNF dissolved in the tap water, respectively, during the experimental period. Changes in body weight, intake of food and water, and organ weight were measured. Serum blood chemistry and histopathological examination of the liver were performed. Administration of SDACNF did not affect body weight change, food and water intake, or organ weights. Administration of SDACNF and CS decreased the diet-induced increase in serum total cholesterol, chylomicron, very-low-density lipoprotein, and phospholipid levels on day 14. Moreover, oral administration of SDACNFs suppressed the increase of alanine transaminase levels on day 29 and suppressed vacuolar degeneration and accumulation of lipid droplets in liver tissue. These data indicate that SDACNF has potential as a functional food for patients with hypercholesterolemia. Full article

(This article belongs to the Special Issue Chitins 2015)

698 KiB

Open AccessArticle

Effects of Plant Growth Hormones on Mucor indicus Growth and Chitosan and Ethanol Production

by Zahra Safaei, Keikhosro Karimi, Poorandokht Golkar and Akram Zamani

Int. J. Mol. Sci. 2015, 16(7), 16683-16694; https://doi.org/10.3390/ijms160716683 - 22 Jul 2015

Cited by 12 | Viewed by 6606

Abstract

The objective of this study was to investigate the effects of indole-3-acetic acid (IAA) and kinetin (KIN) on Mucor indicus growth, cell wall composition, and ethanol production. A semi-synthetic medium, supplemented with 0–5 mg/L hormones, was used for the cultivations (at 32 °C [...] Read more.

The objective of this study was to investigate the effects of indole-3-acetic acid (IAA) and kinetin (KIN) on Mucor indicus growth, cell wall composition, and ethanol production. A semi-synthetic medium, supplemented with 0–5 mg/L hormones, was used for the cultivations (at 32 °C for 48 h). By addition of 1 mg/L of each hormone, the biomass and ethanol yields were increased and decreased, respectively. At higher levels, however, an inverse trend was observed. The glucosamine fraction of the cell wall, as a representative for chitosan, followed similar but sharper changes, compared to the biomass. The highest level was 221% higher than that obtained without hormones. The sum of glucosamine and N-acetyl glucosamine (chitin and chitosan) was noticeably enhanced in the presence of the hormones. Increase of chitosan was accompanied by a decrease in the phosphate content, with the lowest phosphate (0.01 g/g cell wall) being obtained when the chitosan was at the maximum (0.45 g/g cell wall). In conclusion, IAA and KIN significantly enhanced the M. indicus growth and chitosan production, while at the same time decreasing the ethanol yield to some extent. This study shows that plant growth hormones have a high potential for the improvement of fungal chitosan production by M. indicus. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

857 KiB

Open AccessArticle

Production of Galactooligosaccharides Using β-Galactosidase Immobilized on Chitosan-Coated Magnetic Nanoparticles with Tris(hydroxymethyl)phosphine as an Optional Coupling Agent

by Su-Ching Chen and Kow-Jen Duan

Int. J. Mol. Sci. 2015, 16(6), 12499-12512; https://doi.org/10.3390/ijms160612499 - 3 Jun 2015

Cited by 33 | Viewed by 6202

Abstract

β-Galactosidase was immobilized on chitosan-coated magnetic Fe₃O₄ nanoparticles and was used to produce galactooligosaccharides (GOS) from lactose. Immobilized enzyme was prepared with or without the coupling agent, tris(hydroxymethyl)phosphine (THP). The two immobilized systems and the free enzyme achieved their maximum [...] Read more.

β-Galactosidase was immobilized on chitosan-coated magnetic Fe₃O₄ nanoparticles and was used to produce galactooligosaccharides (GOS) from lactose. Immobilized enzyme was prepared with or without the coupling agent, tris(hydroxymethyl)phosphine (THP). The two immobilized systems and the free enzyme achieved their maximum activity at pH 6.0 with an optimal temperature of 50 °C. The immobilized enzymes showed higher activities at a wider range of temperatures and pH. Furthermore, the immobilized enzyme coupled with THP showed higher thermal stability than that without THP. However, activity retention of batchwise reactions was similar for both immobilized systems. All the three enzyme systems produced GOS compound with similar concentration profiles, with a maximum GOS yield of 50.5% from 36% (w·v⁻¹) lactose on a dry weight basis. The chitosan-coated magnetic Fe₃O₄ nanoparticles can be regenerated using a desorption/re-adsorption process described in this study. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Figure 1

1387 KiB

Open AccessArticle

Effect of the Characters of Chitosans Used and Regeneration Conditions on the Yield and Physicochemical Characteristics of Regenerated Products

by Chu Hsi Hsu, Szu Kai Chen, Wei Yu Chen, Min Lang Tsai and Rong Huei Chen

Int. J. Mol. Sci. 2015, 16(4), 8621-8634; https://doi.org/10.3390/ijms16048621 - 17 Apr 2015

Cited by 19 | Viewed by 5170

Abstract

The objective of this study was to explore the effect of the character of chitosans used, and the regeneration conditions employed on, the yield and physicochemical characteristics of regenerated products. Different concentrations of acetic acid were used to dissolve chitosans of 61.7% and [...] Read more.

The objective of this study was to explore the effect of the character of chitosans used, and the regeneration conditions employed on, the yield and physicochemical characteristics of regenerated products. Different concentrations of acetic acid were used to dissolve chitosans of 61.7% and 94.9% degree of deacetylation (DD), and weight-average molecular weight (Mw) of 176 and 97 kDa, respectively; they were then precipitated with an 8 N NaOH solution, followed by washing and neutral and freeze drying to get the regenerated products. Yields of regenerated products and their physicochemical properties, such as ash content, bulk density, Mw, polydispersity index (PDI), DD, and crystallinity were measured. A higher concentration of acetic acid used resulted in a higher yield. The purity of the regenerated product increased significantly, whereas the bulk density and crystallinity decreased significantly after regeneration. The regeneration process showed its merits of narrowing down the PDI of regenerated products. The DD and structure of chitosan was changed insignificantly after the regeneration process. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Figure 1

Review

Jump to: Research

849 KiB

Open AccessReview

Chitosan in Molecularly-Imprinted Polymers: Current and Future Prospects

by Long Xu, Yun-An Huang, Qiu-Jin Zhu and Chun Ye

Int. J. Mol. Sci. 2015, 16(8), 18328-18347; https://doi.org/10.3390/ijms160818328 - 7 Aug 2015

Cited by 104 | Viewed by 12560

Abstract

Chitosan is widely used in molecular imprinting technology (MIT) as a functional monomer or supporting matrix because of its low cost and high contents of amino and hydroxyl functional groups. The various excellent properties of chitosan, which include nontoxicity, biodegradability, biocompatibility, and attractive [...] Read more.

Chitosan is widely used in molecular imprinting technology (MIT) as a functional monomer or supporting matrix because of its low cost and high contents of amino and hydroxyl functional groups. The various excellent properties of chitosan, which include nontoxicity, biodegradability, biocompatibility, and attractive physical and mechanical performances, make chitosan a promising alternative to conventional functional monomers. Recently, chitosan molecularly-imprinted polymers have gained considerable attention and showed significant potential in many fields, such as curbing environmental pollution, medicine, protein separation and identification, and chiral-compound separation. These extensive applications are due to the polymers’ desired selectivity, physical robustness, and thermal stability, as well as their low cost and easy preparation. Cross-linkers, which fix the functional groups of chitosan around imprinted molecules, play an important role in chitosan molecularly-imprinted polymers. This review summarizes the important cross-linkers of chitosan molecularly-imprinted polymers and illustrates the cross-linking mechanism of chitosan and cross-linkers based on the two glucosamine units. Finally, some significant attempts to further develop the application of chitosan in MIT are proposed. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

3070 KiB

Open AccessReview

Adsorption of Silver Nanoparticles onto Different Surface Structures of Chitin/Chitosan and Correlations with Antimicrobial Activities

by Masayuki Ishihara, Vinh Quang Nguyen, Yasutaka Mori, Shingo Nakamura and Hidemi Hattori

Int. J. Mol. Sci. 2015, 16(6), 13973-13988; https://doi.org/10.3390/ijms160613973 - 18 Jun 2015

Cited by 79 | Viewed by 9723

Abstract

Size-controlled spherical silver nanoparticles (Ag NPs) can be simply prepared by autoclaving mixtures of glass powder containing silver with glucose. Moreover, chitins with varying degrees of deacetylation (DDAc < 30%) and chitosan powders and sheets (DDAc > 75%) with varying surface structure properties [...] Read more.

Size-controlled spherical silver nanoparticles (Ag NPs) can be simply prepared by autoclaving mixtures of glass powder containing silver with glucose. Moreover, chitins with varying degrees of deacetylation (DDAc < 30%) and chitosan powders and sheets (DDAc > 75%) with varying surface structure properties have been evaluated as Ag NP carriers. Chitin/chitosan-Ag NP composites in powder or sheet form were prepared by mixing Ag NP suspensions with each of the chitin/chitosan-based material at pH 7.3, leading to homogenous dispersion and stable adsorption of Ag NPs onto chitin carriers with nanoscale fiber-like surface structures, and chitosan carriers with nanoscale porous surface structures. Although these chitins exhibited mild antiviral, bactericidal, and antifungal activities, chitin powders with flat/smooth film-like surface structures had limited antimicrobial activities and Ag NP adsorption. The antimicrobial activities of chitin/chitosan-Ag NP composites increased with increasing amounts of adsorbed Ag NPs, suggesting that the surface structures of chitin/chitosan carriers strongly influence adsorption of Ag NPs and antimicrobial activities. These observations indicate that chitin/chitosan-Ag NPs with nanoscale surface structures have potential as antimicrobial biomaterials and anti-infectious wound dressings. Full article

(This article belongs to the Special Issue Chitins 2015)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Chitins 2015

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issue

Published Papers (15 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI