Preparation and properties of carboxymethyl chitosan/oxidized hydroxyethyl cellulose hydrogel.

Hydrogel wound dressing is a type of hydrophilic polymer, which has been widely studied and applied in biomedical field. In this study, a simple and non-toxic method was developed to prepare a new type of composite hydrogel, which was formed through the Schiff-base reaction between the aldehyde of Oxidized Hydroxyethyl Cellulose (OHEC) and the amino of Carboxymethyl Chitosan (CMCS). Hence, a series of tests toward this new composite hydrogel which contained its structure and performance was applied. Statistics achieved from those tests showed that this composite hydrogel comprised of some high-quality properties such as suitable gelation time, good swelling ability, suitable water evaporation rate, good blood compatibility and biocompatibility. Considering these properties, this hydrogel has a potential to be explored as wound dressing.

Enzymatic synthesis of quaternary ammonium chitosan-silk fibroin peptide copolymer and its characterization.

Free radicals are closely related to the occurrence and development of aging, cancer and inflammation. The aim of the present study was to improve the antioxidant effects of quaternary ammonium chitosan (QCS) by modified with silk fibroin peptide (SFP). The modification had been confirmed by FT-IR and 1H NMR spectroscopy. Degree of substitution (DS) of QCS-SFP could be controlled by adjusting the reaction conditions. In this paper, the results of moisture absorption and retention test showed that QCS-SFP had excellent moisture absorption and retention properties. In vitro antioxidant activity assays demonstrated that, with the DS and concentration increasing of QCS-SFP, the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, hydroxyl radical and hydrogen peroxide (H2O2) increased. Furthermore, the methyl thiazolyl tetrazolium assay (MTT) was applied to evaluate the biocompatibility of QCS-SFP, and the result indicated that QCS-SFP with the DS of 0.32 displayed pronounced cell viability at 100ppm. These results suggested that QCS-SFP would appear to be a promising candidate for wound dressing application.

Preparation and characterization of aminated hyaluronic acid/oxidized hydroxyethyl cellulose hydrogel.

Hydrogel wound dressing is a new type of biomaterial with great absorbent capacity, which has been extensively researched and its application in the field of biomedicine is common. In this study, we prepared a novel composite hydrogel made of hyaluronic acid (HA) and hydroxyethyl cellulose (HEC), both of them are natural polysaccharides. Then, the structure and properties of this composite hydrogel were characterized and tested. The results gained from these studies show that this composite materials have a series of excellent performance such as appropriate gelation time, good swelling ability, suitable water evaporation rate, well hemocompatibility and biological compatibility. In particular, the super absorbent capacity (the maximum swelling rate is 2888%), which is conducive to maintain a moist wound healing environment. Taking account of these properties, this hydrogel can be used clinically as a wound dressing.

Preparation and characterization of chitosan - collagen peptide / oxidized konjac glucomannan hydrogel.

In this paper, the microbial transglutaminase (MTGase) was used as a catalyst to graft the collagen peptide (COP) molecules on the amino group of chitosan to obtain water-soluble chitosan-collagen peptide (CS-COP) derivatives. The preparation of composite hydrogel was via the Schiff-base reaction between the amino of CS-COP and the aldehyde of oxidized konjac glucomannan (OKGM). The hydrogels were characterized by various techniques including Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The results of SEM showed that the hydrogel sample had a clear and stable three-dimensional network structure. Meanwhile, these effects of the addition of OKGM on gelation time, swelling behaviors, water evaporation rate and blood coagulation capacity were investigated. The shortest gelation time for hydrogels was 99.3s. The hydrogels showed a good swelling ability and appropriate water retention capacity. The maximum swelling ratio of the hydrogel was 265%. Dynamic blood clotting test showed that the hydrogels materials had good blood coagulation capacity. Moreover, The biocompatibility of hydrogels was evaluated with NIH-3T3 cells by MTT method. The results indicated that the hydrogels exhibited better biocompatibility. Therefore, this hydrogel has a promising potential to be applied as wound dressing.

Carboxymethyl cellulose modified graphene oxide as pH-sensitive drug delivery system.

Nanotechnology has been studied to improve drug delivery and cancer treatment. The aim of this study is to introduce amino groups into graphene oxide (GO) to form aminated fumed graphene (GO-ADH) and combine GO-ADH with carboxymethyl cellulose (CMC) to produce GO-CMC complex as a drug carrier matrix. The anti-cancer drug small molecule doxorubicin hydrochloride (DOX) was bond to GO-CMC by π-π bond interaction and hydrogen bonding to form GO-CMC/DOX drug loading system. Via the FT-IR, transmission electron microscopy (TEM) and Zeta potential analyzer analysis showed that GO-CMC complex was successfully synthesized. Studies have shown that when pH=5.0, the cumulative release rate of drugs can reach 65.2%, which means it has pH-sensitive ability. The cells were treated with MTT method and human cervical cancer cells (Hela cells) and mouse fibroblasts (NIH-3T3 cells). The results showed that GO-CMC had no obvious cytotoxicity and good biocompatibility.

Synthesis and in vitro antimicrobial and antioxidant activities of quaternary ammonium chitosan modified with nisin.

Nisin had been grafted onto quaternary ammonium chitosan (QCS) through an enzyme-catalyzed reaction to enhance its limited antimicrobial activity. QCS was synthesized by incorporating N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC) onto chitosan's primary amine group. The modification had been confirmed by FT-IR and 1H NMR spectroscopy. Degree of substitution (DS) of QCS-nisin could be controlled by adjusting the reaction conditions. The synthesized compounds were screened in vitro to evaluate their antimicrobial and antioxidant activities. The results suggested that QCS-nisin significantly suppressed the growth of both gram-positive bacteria and gram-negative bacteria; The antioxidant effects on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, hydroxyl radical and hydrogen peroxide (H2O2) proved to be enhanced with increasing DS and concentration. In addition, QCS-nisin showed excellent moisture absorption and retention properties; MTT assay exhibited that QCS-nisin revealed low cytotoxicity effects on cultured NIH-3T3 fibroblasts. These results suggest that QCS-nisin would appear to be a promising candidate for wound dressing application.

Preparation, characterization and antioxidant activity of silk peptides grafted carboxymethyl chitosan.

Free radicals are closely related to the occurrence and development of aging, cancer and inflammation, the ability to scavenge free radicals is an important indicator of the antioxidant activity. In this study, we prepared a water soluble, free radical scavenging and biocompatible copolymer for regenerative therapy. Carboxymethyl chitosan (CMC) was modified with silk peptide (SP) by microbial transglutaminase (MTGase), FT-IR and NMR spectroscopy were used to confirm the successful grafting of SP to CMC. The degree of substitution was determined by ultraviolet spectrophotometry. In vitro antioxidant activity assays demonstrated that, within the scope of study the highest scavenging activity of DPPH was 24.86%, 91% of hydroxyl radical and 36.8% of H2O2. Finally, no relevant cytotoxicity against NIH-3T3 mouse fibroblasts was found for the copolymers. Briefly, our results suggested the potential application of CMC-SP as an antioxidant for regenerative therapy.

Preparation and characterization of hydroxypropyl chitosan modified with nisin.

Nisin had been grafted to hydroxypropyl chitosan (HPCS) using microbial transglutaminase (MTGase) as biocatalyst. HPCS was synthesized from chitosan and propylene oxide under alkali condition. The chemical structures of derivatives were characterized by FT-IR and 1H NMR spectroscopy. The process conditions were optimized from the aspects of the reaction time, the reaction temperature, the molar ratio of nisin to HPCS and the mass ratio of MTGase to HPCS. In this study, the results of moisture absorption and retention tests showed HPCS-nisin had moisture absorption and moisture retention abilities. In addition, in vitro antibacterial activity assessment, HPCS-nisin with the concentration of 0.008mg/mL showed pronounced inhibitory effect against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Furthermore, the methyl thiazolyl tetrazolium assay (MTT) was applied to evaluate the biocompatibility of HPCS-nisin, and the result indicated that HPCS-nisin with the degree of substitution (DS) of 0.18 displayed pronounced cell viability at 500ppm in the range of certain toxicity. Therefore, the results suggest that HPCS-nisin could be potential wound dressings for pharmaceutical applications.