Type Of Chitosan Research Articles

Efficient removal of cadmium from aqueous solution by chitosan grafted pillared bentonite

Developing an environmentally friendly adsorbent with high adsorption capacity and economic advantages is crucial for the treatment of cadmium (Cd)-contaminated wastewater. In this study, Bentonite (Bt), which is widely distributed in nature, was used to prepare a new type of chitosan (CS)-grafted polymerized aluminum-pillared bentonite (i.e., Al@Bt): CS@Al@Bt. This new material effectively addresses the issues of chitosan’s poor mechanical strength, limited load capacity, and the weak adsorption properties of raw bentonite for Cd. The effects of synthesis conditions on Cd adsorption by modified bentonite were investigated through batch experiments. The adsorption mechanism was revealed by characterization tests such as X-ray diffraction (XRD), N2 adsorption-desorption experiments, Scanning and Transmission electron microscopy (SEM-TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results showed that compared to raw Bt, when the ratio of Al in polymerized aluminum to the cation exchange capacity (CEC) of Bt was increased to 5 (i.e., Al/CEC=5), the specific surface area (SSA) of Bt increased from 78.46 m²/g to 195.99 m²/g. Additionally, the interlayer spacing and total pore volume increased by 1.22 and 1.13 times, respectively. After grafting chitosan onto Al@Bt, CS@Al@Bt reached adsorption equilibrium rapidly within 15 min, achieving a removal rate of up to 99.82% (initial concentration of Cd(II) was 20 mg/L, and the solid-liquid ratio was 1 g/L). Additionally, CS@Al@Bt showed good adsorption performance over a wide pH range. The rich pore structure of CS@Al@Bt and the complexation between amino (-NH2) and hydroxyl (-OH) groups with Cd(II) were the main mechanisms for the removal of Cd(II) from the solution. The application showed that CS@Al@Bt effectively reduced Cd-containing mining wastewater from class V to class II quality, underscoring its significant potential for treating Cd(II)-contaminated wastewater.

Pelvic Organ Prolapse Reconstruction with the Chitosan-Based Novel Haemostatic Agent in Ovine Model-Preliminary Report.

This prospective study aimed to assess the feasibility of chitosan biomaterial and subcutaneous gel implantation in an ovine model, with implications for women with genital prolapse. Twenty-four ewes were divided into four groups (n = 6 per group): chitosan type B, chitosan type C, chitosan unmodified injections, and polypropylene mesh. Ovine models were chosen due to their morphological resemblance to human reproductive organs. Animals were sacrificed after 90 days for macroscopic, pathomorphological, and immunohistochemical analysis. In the chitosan type B group, IL-6 and IL-10 levels decreased after 28 days, while chitosan type C and injection groups exhibited higher IL-6 than IL-10 levels. The polypropylene group displayed the highest IL-6 and lowest IL-10 levels. Histological examination of the polypropylene group revealed no degenerative changes or inflammation, whereas chitosan injection induced local inflammation. Other groups exhibited no degenerative changes. Ewes implanted with chitosan displayed reduced inflammation compared to polypropylene-implanted ewes. Chitosan implantation facilitated vaginal tissue healing, in contrast to polypropylene mesh, which led to extrusion. While chitosan holds promise as an alternative to polypropylene mesh, further research is imperative for comprehensive evaluation. This study suggests the potential of a chitosan biomaterial in pelvic organ prolapse treatment, warranting additional investigation.

Chitosan-Based Beads Incorporating Inorganic-Organic Composites for Copper Ion Retention in Aqueous Solutions.

In recent years, there has been a challenging interest in developing low-cost biopolymeric materials for wastewater treatment. In the present work, new adsorbents, based on different types of chitosan (commercial, commercial chitin-derived chitosan and chitosan synthesized from shrimp shell waste) and inorganic-organic composites have been evaluated for copper ions removal. The efficacy of the synthesis of chitosan-based composite beads has been determined by studying various characteristics using several techniques, including FTIR spectroscopy, X-ray diffraction, porosimetry (N2 adsorption), and scanning electron microscopy (SEM). Adsorption kinetics was performed using different adsorption models to determine the adsorption behavior of the materials in the aqueous media. For all composite beads, regardless of the type of chitosan used, good capacity to remove copper ions from simulated waters was observed (up to 17 mg/g), which proves that the new materials hold potential for heavy metal retention. However, the adsorption efficiency was influenced by the type of chitosan used. Thus, for the series where commercial chitosan (CC) was used, the removal efficiency was approximately 29%; for the series with chitosan obtained from commercial chitin (SC), the removal efficiency was approximately 34%; for the series with chitosan enriched with CaCO3 (SH), the removal efficiency was approximately 52%.

Synthesis and characterization of chitosan-polyacrylamide cryogels for the purification of human IgG by IMAC

The performance of polyacrylamide-chitosan monolithic cryogels functionalized with iminodiacetic acid (IDA) was evaluated for the chromatographic separation of Immunoglobulin G (hIgG) from human serum using immobilized metal ion affinity chromatography (IMAC). Monoliths were prepared using the cryopolimerization technique, varying the type of chitosan (CS) used, and final concentrations of allyl glycidyl ether (AGE) and glutaraldehyde (GA), keeping the amount of acrylamide (AAm) and bisacrylamide (MBAm) constant. Cryogels were characterized by their surface area, SEM, FTIR, porosity, ligand density, mechanical resistance, and flow rate. Purification of hIgG was investigated using the PAAm-CS-GA-AGE-IDA cryogel chelated with Cu(II) and Ni(II) ions. The analysis demonstrated isolation of hIgG from human serum in a sodium phosphate buffer at pH 7.0 containing 2 mmol/L imidazole on PAAm-CS-GA-AGE-IDA-Ni(II) cryogel, with purity of 96% and purification factor of 12.4 (based on total protein concentration and radial immunodiffusion). The hIgG adsorption equilibrium data on the IDA-Ni(II) cryogel followed the Langmuir–Freundlich isotherm model, showing maximum hIgG binding capacity of 31.19 mg hIgG/g dry cryogel and a dissociation constant in the order of 10−7 to 10−8 mol/L. These results demonstrate the potential of PAAm/CS-based cryogels with chelated Ni(II) ions for the purification of hIgG from human serum using IMAC.

Synthesis, Characterization and Biological Properties of Type I Collagen-Chitosan Mixed Hydrogels: A Review.

Type I collagen and chitosan are two of the main biological macromolecules used to design scaffolds for tissue engineering. The former has the benefits of being biocompatible and provides biochemical cues for cell adhesion, proliferation and differentiation. However, collagen hydrogels usually exhibit poor mechanical properties and are difficult to functionalize. Chitosan is also often biocompatible, but is much more versatile in terms of structure and chemistry. Although it does have important biological properties, it is not a good substrate for mammalian cells. Combining of these two biomacromolecules is therefore a strategy of choice for the preparation of interesting biomaterials. The aim of this review is to describe the different protocols available to prepare Type I collagen-chitosan hydrogels for the purpose of presenting their physical and chemical properties and highlighting the benefits of mixed hydrogels over single-macromolecule ones. A critical discussion of the literature is provided to point out the poor understanding of chitosan-type I collagen interactions, in particular due to the lack of systematic studies addressing the effect of chitosan characteristics.

Synergistic depolymerisation of alginate and chitosan by high hydrostatic pressure (HHP) and pulsed electric fields (PEF) treatment in the presence of H2O2

Physically-induced depolymerisation procedures are often preferred for obtaining alginate and chitosan oligosaccharides as they either do not use or make minimal use of additional chemicals; therefore, separation of the final products is facile. In this work, solutions of three types of alginate with different mannuronic and guluronic acid residues ratio (M/G ratio) and molecular weights (Mw) and one type of chitosan were non-thermally processed by applying high hydrostatic pressures (HHP) up to 500 MPa (20 min) or pulsed electric fields (PEF) up to 25 kV cm−1 (4000 μm) in the absence or presence of 3 % hydrogen peroxide (H2O2). The impact on the physicochemical properties of alginate and chitosan was investigated by rheology, GPC, XRD, FTIR, and 1H NMR. In the rheological investigations, the apparent viscosities of all samples decreased with increasing shear rate, indicating a non-Newtonian shear-thinning behaviour. GPC results reported Mw reductions that ranged between 8 and 96 % for all treatments. NMR results revealed that HHP and PEF treatment predominantly reduced the M/G ratio of alginate and the degree of deacetylation (DDA) of chitosan, whilst H2O2 promoted an increase in the M/G ratio in alginate and DDA of chitosan. Overall, the present investigation has demonstrated the feasibility of HHP and PEF for rapidly producing alginate and chitosan oligosaccharides.

3D printing of ‘green’ thermo-sensitive chitosan-hydroxyapatite bone scaffold based on lyophilized platelet-rich fibrin

The critical bone defect is still an urgent problem in the field of bone repair. Here, we reported a new type of chitosan (CS)–hydroxyapatite (HAP) scaffolds based on lyophilized platelet-rich fibrin (L-PRF) for releasing abundant growth factors to realize their respective functions. It also has strong mechanical properties to maintain the stability of the bone repair environment. However, acid-soluble CS hydrogels often contain toxic and organic solvents. Moreover, chemical agents may be used for cross-linking for better mechanical properties, further increasing cytotoxicity. In this study, we used an alkali/urea dissolution system to dissolve CS, which improved its mechanical properties and made it thermo-sensitive. Finally, the L-PRF-CS-HAP (P-C-H) composite scaffold was constructed by extrusion-based printing. The results showed that the printing ink had desirable printability and temperature sensitivity. The compressive properties of the scaffolds exhibited a trend of decline with L-PRF content increasing, but all of them could meet the strength of cancellous bone. Meanwhile, the scaffolds had high hydrophilicity, porosity, and could be degraded stably in vitro. The antibacterial properties of the scaffolds were also verified, greatly reducing the risk of infection during bone repair. It was also demonstrated that the release time of growth factor from L-PRF was significantly prolonged, and growth factor could still be detected after 35 d of sustained release. The capacity of cells to proliferate increased as the number of L-PRF components increased, indicating that L-PRF still exhibited biological activity after 3D printing.

Histological Changes in Liver and Cardiac Rat Tissues after Exposure to Chitosan Nanoparticles Orally

Background: As safe natural biopolymer, chitosan is resulting from chitin deacetylation. Owing to its antimicrobial and antifungal effects, chitosan and/or its biological derivatives have gained extensive interest. The antibacterial activity of chitosan exhibits only in a low pH medium since its solubility above pH 6 is poor. Several factors affect chitosan antibacterial action such as chitosan type, polymerization degree, and certain other chemicophysical features. Objectives: The current study was intended to inspect the chitosan injury on hepatic and myocardial cells in rats in different concentrations. Materials and Methods: Chitosan was purchased and prepared at various concentrations. Laboratory Wistar albino rats were orally fed with different concentrations of chitosan. Histological examination of rat liver and cardiac tissues was performed accordingly. Results: A noticeable increase in animal weight is seen as the concentration of chitosan increases. Normal histological appearance with slight hemorrhaging and abnormal histological appearance with more abundant hemorrhaging and cellular vacuolation were present in liver tissues. Profound histological damage with more abundant hemorrhaging and lymphocytic infiltration along with sinusoid enlargement in the liver as well as districted nuclei was also present. Cardiac tissues were less affected by changes in chitosan concentration. Liver histological changes are attributed to the metabolic breakdown of chitosan in the liver. A noticeable decrease in vascular thickness is seen in both cardiac and liver vascular networks. Conclusion: The study found that chitosan has robust cytotoxic influences on certain organs. However histological damage is more prominent and is seen in rat liver tissues. Histological damage is confirmed by the abnormality of histological and cellular damage seen.

Water-soluble chitosan eases development of mucoadhesive buccal films and wafers for children

Oromucosal films and wafers are user-friendly solid dosage forms offering easy and convenient administration, as well as rapid or controlled drug delivery. The aim of this study was to develop prednisolone containing child-friendly chitosan-based mucoadhesive films and wafers with a prolonged residence time on the buccal mucosa. Four different chitosan types (different molecular weights, degree of deacetylation (DDA), pattern of deacetylation) were studied for films prepared by solvent-cast-evaporation and wafers by freeze-drying. Mucoadhesive properties correlated with swelling abilities and were dependent on the chitosan type, the solvent, and the preparation method. Mucoadhesive forces were higher for formulations containing chitosan with higher DDA and for wafers compared to films. The drug release was relatively fast, especially for films (approx. 90 % in 15 minutes) and steadier for wafers (90 % in 45–120 minutes). Permeability was evaluated using artificial membranes and HT29-MTX cell-monolayers. The developed formulations exhibited good biocompatibility. Organoleptic properties can be improved by choosing a homogenously deacetylated chitosan type that provides a more neutral pH. Using hydroxypropyl-beta-cyclodextrin-complexation for taste masking of bitter drugs also reduced wafers’ drug release rate. Mucoadhesive wafers are promising alternatives to films with a slower drug release rate and stronger mucoadhesion.

Extraction and characterization of chitosan from Eupolyphaga sinensis Walker and its application in the preparation of electrospinning nanofiber membranes

Due to its capabilities for wound healing, antimicrobial defense, hemostasis, and biodegradation, chitosan has seen increased use in biomedical disciplines in recent years. In the meantime, efforts have been made to develop and use insect chitosan as a source to address the seasonal, irritating, and regional shortcomings of traditional shrimp and crab chitosan. In this study, a new type of insect chitosan (DCS) was first extracted from Eupolyphaga sinensis Walker by a low-temperature intermittent method and was compared with commercially available pharmaceutical chitosan (CS). Firstly, the degree of deacetylation and molecular weight of DCS were determined, and DCS was characterized by FT-IR, 1H NMR, XRD, and TGA-DTG. On this basis, DCS was mixed with PVA and PEO to create a novel electrospun nanofiber membrane. The air permeability, antibacterial properties, and biocompatibility of the nanofiber membrane were evaluated, as well as the membrane's shape, structure, and mechanical characteristics. Finally, the activity of nanofiber membranes in promoting wound healing was verified with a rat full-thickness skin defect model, hoping to provide a reference for the development of new drug delivery carriers and wound dressings.

Assessment of chitosan antimicrobial effect on wine microbes

Chitosan is an active highly charged polysaccharide that has initially been developed in oenology to eliminate the spoilage yeast B. bruxellensis. However, different forms of chitosan exist, some complying with EU regulation for their use in wines, others not. Moreover, with the trend in oenology of limiting SO2, more and more questions arise as to the impact of chitosan on other microorganisms of the grape and wine environment.We investigated the antimicrobial efficiency of chitosan on a large oenological microbial collection, englobing technological as well as spoilage microorganisms. Results show that most species are affected at least transiently. Furthermore, a high variability prevails within most species and sensitive, intermediate and tolerant strains can be observed. This study also highlights different efficiencies depending on the wine parameters or the winemaking stage, giving important indications on which winemaking issues can be solved using chitosan.Chitosan treatment does not seem to be appropriate to limit the musts microbial pressure and Saccharomyces cerevisiae cannot be stopped during alcoholic fermentation, especially in sweet wines. Likewise, acetic acid bacteria are poorly impacted by chitosan. After alcoholic fermentation, chitosan can efficiently limit non-Saccharomyces yeast and lactic acid bacteria but special care should be given as to whether malolactic fermentation is wanted or not. Indeed, O. oeni can be severely impacted by chitosan, even months after treatment.Finally, this study highlights the crucial importance of the chitosan type used in its efficiency towards microbial stabilization. While a high molecular weight chitosan has limited antimicrobial properties, a chitosan with a much lower one, complying with EU and OIV regulation and specifications for its use in wine is much more efficient.

Taguchi Grey Relational Analysis for Multi-Response Optimization of Bacillus Bacteria Flocculation Recovery from Fermented Broth by Chitosan to Enhance Biocontrol Efficiency.

Degradation of environment is a challenge to crop production around the world. Biological control of various plant diseases using antagonistic bacteria is an encouraging alternative to traditionally used chemical control strategies. Chitosan as a well-known natural flocculation agent also exhibits antimicrobial activity. The goal of this study was to investigate a dual nature of chitosan in flocculation of Bacillus sp. BioSol021 cultivation broth intended for biocontrol applications. Experiments were performed based on L18 standard Taguchi orthogonal array design with five input parameters (chitosan type and dosage, pH value, rapid and slow mixing rates). In this study, the grey relational analysis was used to perform multi-objective optimization of the chosen responses, i.e., flocculation efficiency and four inhibition zone diameters against the selected phytopathogens. The results have indicated a great potential of a highly efficient method for removal of the Bacillus bacteria from the cultivation broth using chitosan. The good flocculation efficiency and high precipitate antimicrobial activity against the selected phytopathogens were achieved. It has been shown that multiple flocculation performance parameters were improved, resulting in slightly improved response values.

An asymmetric wettable PCL/chitosan composite scaffold loaded with IGF-2 for wound dressing.

An effective dressing is essential for wound healing. In fact, the wettability performance is one of the most important factors of a wound dressing. The fundamental functions of a wound dressing involve the absorption of excess exudates and maintenance of optimal moisture at the wound by controlling water evaporation. Here, we designed a type of chitosan (CS) sponge and PCL nanofibrous membrane composite dressing with asymmetric wettability surfaces as wound healing materials for biomedical applications. The hydrophobic surfaces of the composite dressing were waterproof and could efficiently control the water vapor transmission rate, whereas the hydrophilic surface of the CS sponge had good cytocompatibility and water-absorbing capability. Insulin-like growth factor-2 (IGF-2) was added to the CS sponge, and exhibited a stimulatory effect on fibroblasts migration and proliferation. Therefore, the fabricated CS sponge and PCL membrane composite dressing had excellent cytocompatibility, vapor transmission rate, and liquid absorption and asymmetric wettability, suggesting its potential as a promising alternative to traditional wound dressing.

꾸지뽕나무 열매 추출물의 Chlorogenic Acid, Rutin 함량 분석 및 생리활성

This study was carried out to very precisely understand the effect of solvent selection on the molecular properties in the investigation of the biological activity according to the molecular size of chitosan. Chitosan hydrolysates derived from the hydrolysis of high molecular weight chitosan (HMWC) were prepared in enzymatic hydrolysis under solvent selective conditions. Chitosan hydrolysates were characterized by HPLC and Matrix-Assisted Laser Desorption/ Ionization-Time of Flight (MALDI-TOF) mass spectrometry analyses, respectively. HPLC analysis did not show a significant difference in the size of hydrolysates according to the type of chitosan. On the other hand, it was confirmed that each molecular size was significantly different from the results presented by HPLC with MALDI-TOF mass spectrometry analysis. In addition, the effect on the antibacterial activity of the hydrolysates of chitosan, designated to “active molecular chitosan (AMC)”, by the solvent selected for the enzymatic reaction also showed a significant difference. Therefore, it is intended to suggest that the selection of solvents for the enzymatic reaction for chitosan hydrolysis and their antibacterial activity is very important.

Mupirocin-Loaded Chitosan Microspheres Embedded in Piper betle Extract Containing Collagen Scaffold Accelerate Wound Healing Activity.

This study reports the formulation of mupirocin-loaded chitosan microspheres embedded in Piper betle extract containing collagen scaffold as combinational drug delivery for improved wound healing. Selection of chitosan type (molecular weight and degree of deacetylation) was carried out based on their antibacterial efficacy. The low molecular weight chitosan was selected owing to the highest antibacterial action against gram-positive as well as gram-negative bacteria. Low molecular weight chitosan-microspheres showed spherical shape with largely smooth surface morphology, 11.81% of mupirocin loading, and its controlled release profile. The XRD, DSC thermograms, and FT-IR spectral analysis revealed the mupirocin loaded in molecularly dispersed or in amorphous form, and having no chemical interactions with the chitosan matrix, respectively. The in vivo study indicates potential effect of the mupirocin, Piper betle, and chitosan in the collagen scaffold in the wound healing efficiency with approximately 90% wound healing observed at the end of 15 days of study for combinational drug-loaded chitosan microspheres-collagen scaffold-treated group. The histopathology examination further revealed tissue lined by stratified squamous epithelium, collagen deposition, fibroblastic proliferation, and absence of inflammation indicating relatively efficient wound healing once treated with combinational drug-loaded chitosan microspheres containing scaffold.

The Effect of Chitosan Type on Biological and Physicochemical Properties of Films with Propolis Extract.

The aim of the research was to determine the influence of chitosan type and propolis extract concentration on biological and physicochemical properties of chitosan-propolis films in terms of their applicability in food packaging. The films were prepared using three types of chitosan: from crab shells, medium and high molecular weight and propolis concentration in the range of 0.75–5.0%. The prepared polysaccharide films were tested for antimicrobial properties, oxygen transmission rate (OTR) and water vapor transmission rate (WVTR). Moreover, sorption tests and structural analysis were carried out. Microbiological tests indicated the best antimicrobial activity for the film consisting of high molecular weight chitosan and 5.0% propolis extract. Both the type of chitosan and propolis concentration affected transmission parameters—OTR and WVTR. The best barrier properties were recorded for the film composed of high molecular weight chitosan and 5.0% propolis extract. The results of sorption experiments showed a slight influence of chitosan type and a significant effect of propolis extract concentration on equilibrium moisture content of tested films. Moreover, propolis extract concentration affected monolayer water capacity (Mm) estimated using the Guggenheim, Anderson and de Boer (GAB) sorption model. The obtained results indicate that chitosan films with an addition of propolis extract are promising materials for food packaging applications, including food containing probiotic microorganisms.

The effect of chitosan type and drug-chitosan ratio on physical characteristics and release profile of ketoprofen microparticles prepared by spray drying.

In order to minimize gastrointestinal irritation and to extend the absorption of ketoprofen, microparticles prepared with chitosan have been developed. In this study, chitosan type and drug-chitosan ratio were investigated to prepare microparticles of ketoprofen and evaluated for physical characteristics and drug release profiles. Microparticles were prepared by using ionic gelation methods with chitosan, which has two different viscosities i.e.,19 and 50cPs, cross-linked with tripolyphosphate, and dried by spray drying method. The microparticles were made with a drug-chitosan ratio of 5:15 and 6:15. The results showed that the microparticles had spherical shapes. Increasing the amount of ketoprofen improved the drug content and entrapment efficiency. Evaluation of drug release in simulated intestinal fluid (pH6.8) showed that the microparticles prepared with chitosan 19cPs had the slowest release rate than those of chitosan 50cPs, while that of the microparticles prepared with chitosan 50cPs with the ratio of drug/polymer 6:15 was the fastest, as shown by its slope value. The release rate of microparticles with chitosan 19cPs was slower than those microparticles with chitosan 50cPs. It could be suggested that by increasing the amount of ketoprofen, it improved the entrapment efficiency and the release rate of microparticles.

Design of bioreactor based on immobilized laccase on silica-chitosan support for phenol removal in continuous mode

A silica-chitosan support was employed for laccase immobilization. The hybrid support was obtained using calcium ion as linking agent that coordinates silanol and hydroxyl groups of chitosan. The insoluble biocatalyst was then packed in a column and used in a flow system for phenol removal. The immobilized enzyme reactor (IMER) showed a good storage stability (70 % of activity in 70 days) and good reusability (90−50 % of catalytic activity at the 4th reuse in function of chitosan type). The best performance for the phenol removal was obtained with a low molecular weight chitosan from crab shells at pH 5 and with a flow rate of 0.7 mL/min. The apparent Michaelis–Menten (Vmaxapp, Kmapp) and the inherent (Vmaxinh, Kminh) constants were also determined to evaluate the influence of the phenol structure on the performance of the system. The enzymatic oxidation of a phenol mixture (4-methylcatechol, catechol, caffeic acid, syringic acid, vanillic acid, p-coumaric acid, and tyrosol) was followed for 21 h in a continuous mode by HPLC. The phenol mixture removal of 90 % was also confirmed by Folin‐Ciocalteu assay.

Antibacterial Effect on Enterococcus Faecalis and Physical Properties of Chitosan Added Calcium Hydroxide Canal Filling Material

The aim of this study was to evaluate the antibacterial effect on Enterococcus Faecalis and physical properties of chitosan added calcium hydroxide canal filling material.<br/>Low, medium, high molecular weights of chitosan powder were mixed with calcium hydroxide canal filling material. Also, for each molecular weight group, 1.0, 2.0, 5.0 wt% of chitosan powder were added. An overnight culture of <i>E. faecalis</i> was adjusted to 1 × 10<sup>6</sup> CFU/ml. For test of antibacterial effect, three different molecular weights of 2.0 wt% chitosan and three different concentrations of high molecular weight chitosan were mixed with calcium hydroxide canal filling material. The absorbance of plates was analyzed using spectrophotometer at 570 nm with a reference wavelength of 600 nm. Physical properties such as flow, film thickness and radiopacity were examined according to ISO 6876 : 2012.<br/>All molecular weight type of chitosan containing material showed inhibitory effect against E. faecalis growth compared to non-chitosan added calcium hydroxide canal filling material group (<i>p</i> < 0.05). High molecular weight chitosan containing material showed the most antibacterial effect. Also, the antibacterial effect decreased as the incorporated amount of chitosan decreased (<i>p</i> < 0.05). Every molecular weight group of material containing chitosan had a tendency for reduced flow and radiopacity, increased film thickness according to amount of chitosan. Low molecular weight of 1.0 wt% chitosan addition did not show any significant difference of physical properties compared to conventional calcium hydroxide canal filling material.<br/>In conclusion, for reinforcement of antibacterial effect against <i>E. faecalis</i> and for favorable physical properties, 2.0 wt% of chitosan adding is recommended. Considering its antibacterial effect of chitosan, further studies are required for clinical application of chitosan in endodontics and pediatric dentistry.

Ultrafast Fabrication of Self-Healing and Injectable Carboxymethyl Chitosan Hydrogel Dressing for Wound Healing.

Herein, a new type of injectable carboxymethyl chitosan (CMCh) hydrogel wound dressing with self-healing properties is constructed. First, CMCh samples are homogeneously synthesized in alkali/urea aqueous solutions. Subsequently, trivalent metal ions of Fe3+ and Al3+ are introduced to form coordination bonds with CMCh, leading to an ultrafast gelation process. A series of hydrogels can be obtained by altering the concentration of CMCh and the relative content of metal ions. Owing to the dynamic and reversible characteristics of the coordination bonds, the hydrogel exhibits self-healing, self-adaption, and thermoresponsive ability. Moreover, due to the interaction between the amino groups on CMCh and SO42-, the hydrogel undergoes phase separation and can be painlessly detached from the skin with little residue. Taking advantage of all these characteristics, the hydrogel is used as a wound dressing and can significantly accelerate skin tissue regeneration and wound closure. This hydrogel has great potential in the application of tissue engineering.