Functional advanced biopolymers have received far less attention than renewable biomass (cellulose, rubber, etc.) used for energy production. Among the most advanced biopolymers known is chitosan. ...The term chitosan refers to a family of polysaccharides obtained by partial de-N-acetylation from chitin, one of the most abundant renewable resources in the biosphere. Chitosan has been firmly established as having unique material properties as well as biological activities. Either in its native form or as a chemical derivative, chitosan is amenable to being processed—typically under mild conditions—into soft materials such as hydrogels, colloidal nanoparticles, or nanofibers. Given its multiple biological properties, including biodegradability, antimicrobial effects, gene transfectability, and metal adsorption—to name but a few—chitosan is regarded as a widely versatile building block in various sectors (e.g., agriculture, food, cosmetics, pharmacy) and for various applications (medical devices, metal adsorption, catalysis, etc.). This Special Issue presents an updated account addressing some of the major applications, including also chemical and enzymatic modifications of oligos and polymers. A better understanding of the properties that underpin the use of chitin and chitosan in different fields is key for boosting their more extensive industrial utilization, as well as to aid regulatory agencies in establishing specifications, guidelines, and standards for the different types of products and applications.
Chitosan as a starting material for wound healing applications Patrulea, V.; Ostafe, V.; Borchard, G. ...
European journal of pharmaceutics and biopharmaceutics,
November 2015, 2015-Nov, 2015-11-00, 20151101, Letnik:
97, Številka:
Pt B
Journal Article
Recenzirano
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Chitosan and its derivatives have attracted great attention due to their properties beneficial for application to wound healing. The main focus of the present review is to summarize ...studies involving chitosan and its derivatives, especially N,N,N-trimethyl-chitosan (TMC), N,O-carboxymethyl-chitosan (CMC) and O-carboxymethyl-N,N,N-trimethyl-chitosan (CMTMC), used to accelerate wound healing. Moreover, formulation strategies for chitosan and its derivatives, as well as their in vitro, in vivo and clinical applications in wound healing are described.
Mucoadhesive drug delivery systems are desirable as they can increase the residence time of drugs at the site of absorption/action, provide sustained drug release and minimize the degradation of ...drugs in various body sites. Chitosan is a cationic polysaccharide that exhibits mucoadhesive properties and it has been widely used in the design of mucoadhesive dosage forms. However, its limited mucoadhesive strength and limited water-solubility at neutral and basic pHs are considered as two major drawbacks of its use. Chemical modification of chitosan has been exploited to tackle these two issues. In this review, we highlight the up-to-date studies involving the synthetic approaches and description of mucoadhesive properties of chitosan and chitosan derivatives. These derivatives include trimethyl chitosan, carboxymethyl chitosan, thiolated chitosan, chitosan-enzyme inhibitors, chitosan-ethylenediaminetetraacetic acid (chitosan-EDTA), half-acetylated chitosan, acrylated chitosan, glycol chitosan, chitosan-catechol, methyl pyrrolidinone-chitosan, cyclodextrin-chitosan and oleoyl-quaternised chitosan. We have particularly focused on the effect of chemical derivatization on the mucoadhesive properties of chitosan. Additionally, other important properties including water-solubility, stability, controlled release, permeation enhancing effect, and in vivo performance are also described.
Ciprofloxacin, a biotoxic micropollutant, is ubiquitously found in the water environment, which is a global concern. This study developed polymeric S-C
N
/ZnO-Chitosan (indexed as SCZ-CH) hydrogels ...for degrading Ciprofloxacin. The SCZ-CH hydrogels provided the Ciprofloxacin degradation efficiencies of ~93% and ~69% in UV and visible lights, respectively, at optimum conditions (SCZ-CH hydrogels with 2 g/L SCZ, 20 mg/L initial concentration, pH 5, and room temperature). In addition, immobilized SCZ-CH hydrogels structures enable easy separation of the SCZ catalyst from water. The spectroscopic and microscopic analyses of SCZ-CH hydrogels show multifaceted properties, like high oxygen concentrations, crystallinity, stacked structure, high roughness, and improved bandgap energy, which are responsible for the enhanced photocatalytic activity. The effects of water matrix and experimental conditions on Ciprofloxacin degradation were also studied, which suggested that the catalyst dose and solution pH have significant effects on photocatalytic activity. SCZ-CH hydrogels have shown good mineralization efficiency (~98%) and reusability (up to 10 cycles) for Ciprofloxacin removal. Superoxide radicals played an essential role in the degradation of Ciprofloxacin. The Ciprofloxacin molecules get degraded by driving radicals through oxidation, defluorination, substitution, and breaking of the rings. The proposed SCZ-CH hydrogels can be effectively used at a large scale to treat micropollutants.
The detection of heavy metals, such as Hg
and Fe
, is of great significance. In this work, fluorescent small-molecule BODIPY (BY-3) bearing CC group was synthesized firstly. And then, the ...chitosan-based polymer sensor CY-1 was synthesized through the spontaneous NH
/C≡C click reaction. The synthesized CY-1 can effectively bind and recognize Hg
/Hg
by the -C=N groups formed in the click reaction. Moreover, the macromolecular sensors CS-1 and CS-2 were synthesized by incorporating another recognition sites to CY-1. These synthesized macromolecular sensors can not only recognize Hg
/Hg
, but also effectively recognize Fe
/Fe
. All of them exhibited significant quenching effect, visible to the naked eye under UV irradiation. The detection limit of CY-1 for Hg
was 1.51 × 10
mol/L, and the detection limit of CS-2 for Fe
was 2.30 × 10
mol/L. The BODIPY-chitosan sensors synthesized in this work have the functions of removing heavy metal ions besides the identifying ability. The maximum adsorption capacity of 1 g chitosan to Hg
was 108 mg as the best one. This article provides a new method to prepare macromolecular sensors for the detection and removal of heavy metal ions. As a useful natural polymer, chitosan's application scope was enlarged.
Modified chitosan with various functional groups has high potential as an efficient adsorbent in removing water pollution. In this study, new magnetic adsorbent, bio-based chitosan/Fe
O
/NiFe
O
, was ...successfully prepared by green chemistry route involving mixing of chitosan as core moiety and Fe
O
/NiFe
O
nanocomposite, and slow evaporation of solvent. Synthesized chitosan/Fe
O
/NiFe
O
was characterized by FT-IR, TGA, XRD, VSM and FE-SEM. The FT-IR and XRD results confirmed that the successful preparation of chitosan/Fe
O
/NiFe
O
. Uniform dispersion of Fe
O
/NiFe
O
nanoparticles with low aggregation was confirmed by FE-SEM. The as-prepared magnetic chitosan/Fe
O
/NiFe
O
was developed as solid phase adsorbent to remove methyl green (MG) dye from aqueous solutions. Several important parameters such as contact time, pH, temperature and adsorbent dosage were investigated systematically. The high and fast MG dye removal (≈ 80%) occurs after 30 min. The optimal conditions for MG removal was recorded at pH = 8, contact time of 60 min, adsorbent dosage of 0.2 g and 25 °C and displayed a high MG dye removal percentage of 96.51% and adsorption capacity of 77.22 mg/g.
In this study, the Cu
MoS
/WO
supported on chitosan was prepared by precipitation method, and applied to photocatalyst, antibacterial agent and biosensor. The presence of WO
and Cu
MoS
crystals were ...confirmed by XRD analysis. The elemental information was investigated by EDS. FTIR spectra shows the presence of chitosan in nanocomposites. The as-synthesized Cu
MoS
/WO
/Chitosan nanocomposites has a bandgap of 2.18 eV and it is effective for visible light condition. The average particle size of the Cu
MoS
/WO
/Chitosan is 71 nm. The photocatalysis activity Cu
MoS
/WO
/Chitosan was higher than Cu
MoS
or WO
.The Cu
MoS
/WO
/Chitosan nanocomposites shows the highest efficiency (100%) in photocatalysis degradation of dye under visible light irradiation in 80 min. The •O
plays a main role in degradation process. The as-synthesized Cu
MoS
/WO
/Chitosan nanocomposites depicted the antibacterial activity toward G+/- bacteria. Determination of enterococcus faecalis is important for human health. The DNA template was used to the Cu
MoS
/WO
/Chitosan nanocomposites and applied in detection of enterococcus faecalis by H
O
and 3,3',5,5' -tetramethylbenzidine in peroxidase like activity. The detection limit of enterococcus faecalis by DNA-Cu
MoS
/WO
/Chitosan in peroxidase-like catalysis was about 55 CFU/mL. Therefore, the Cu
MoS
/WO
/Chitosan can be applied in the photocatalysis, bactericidal and peroxidase process.
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