Structure Of Chitosan Research Articles

Experimental Reconstruction of Critical Size Defects of Bone Tissue in the Maxillofacial Region When Using Modified Chitosan

Rationale: The authors of the article propose a biomaterial design based on highly deacetylated chitosan, which replaces extensive bone defects. In the work, a biomaterial was used included freeze-dried implants based on highly deacetylated and high molecular weight chitosan, containing natural polysaccharides and inorganic nano-structural hydroxyapatite by intervention in white laboratory rats. Objectives: The goal is achieved due to the fact that a gel mass containing 2% chitosan ascorbate with a molecular weight of 100-700 kDa and a degree of deacetylation of 95-98% is introduced into large cavities. Sub-periosteal implantation of a chitosan structure into bone defects, CT analysis, morphometric analysis of histological sections of a bone defect allow us to reveal high efficiency in the early stages of bone reconstruction. Findings: When using modified chitosan to fill extensive bone defects in the jawbone in animals, the process of defect replacement occurs after 4-5 weeks with the formation of a full-fledged new bone tissue compared to control animals. Morphological analysis of the bone defect on the 7th day after the intervention showed signs of cancellous bone tissue formation, two weeks later - a pronounced increase in bone tissue volume (P <0.01). In the group with modified chitosan implantation, the amount of connective tissue formation was significantly lower (P <0.05) compared to the control group. CT analysis showed that after 6 weeks after the intervention, the closure of the defect by 70-80% is recorded, after 8 weeks - complete 100% closure of the defect without disturbing the morphology of the bone with a high degree of mineralization. Conclusions: Thus, modified chitosan is capable of eliminating bone defects of a critical size in the maxillofacial region, detecting early signs of angiogenesis and new bone formation, and serving as a promising material in reconstructive dentistry

Preparation of new MOF-808/chitosan composite for Cr(VI) adsorption from aqueous solution: Experimental and DFT study

In this study, a series of Zirconium-based MOF and chitosan composites (MOF-808/chitosan) were synthesized as efficient adsorbent for Cr(VI) ions elimination from aqueous solution. MOF-808/chitosan structure and morphology was characterized by FE-SEM, EDX, XRD, BET, zeta potential analysis, FT-IR, XPS techniques. The kinetic studies ascertained that Cr(VI) adsorption over MOF-808/chitosan followed pseudo-second-order kinetic model. The adsorption isotherms fitted the Langmuir isotherm model, implying on homogeneously adsorption of Cr(VI) on the surface of MOF-808/chitosan. According to the Langmuir model, the maximum capacity was obtained to be 320.0 mg/g at pH 5. Thermodynamic investigation proposed spontaneous (ΔG° < 0), disordered (ΔS° > 0) and endothermic (ΔH° > 0) for adsorption process. Besides, MOF-808/chitosan displayed an appropriate reusability for the elimination of Cr(VI) ions from their aqueous solutions for six successive cycles. DFT study of the adsorption process displayed and confirmed the role of hydrogen bonding and electrostatic attraction simultaneously.

Methods for crosslinking and stabilization of chitosan structures for potential medical applications

Chitosan is a well-known polymer widely used in tissue engineering and regenerative medicine. It is biocompatible, biodegradable, non-toxic, has antibacterial and osteoconductive properties. Chitosan is often used in the form of composites (with the participation of ceramic particles), membranes, hydrogels or nanoparticles. The problem with biomaterials is their low durability, rapid degradation, poor mechanical properties and cytotoxicity. Cross-linking or stabilization of such materials allows for solving these problems. It is important that the compounds used for this purpose exhibit limited or no toxicity. The presented article is a review and presents some methods of cross-linking/stabilization of chitosan structures. The analysis concerns low or non-cytotoxic cross-linking/stabilization methods. The discussed compounds used for the purpose of chitosan structure fixation are: cinnamaldehyde, genipin, L-aspartic acid, vanillin, sodium carbonate, sodium alginate, BGP, ethanol and TPP. There is discussed also a hydrothermal/dehydrothermal method which seems to be promising as it is more advantageous since no additional compounds are introduced into the structure.

Effect of pH value and the distance between the electrodes on physicochemical properties of chitosan under SPP treatment

Solution plasma process (SPP) was employed to degrade chitosan. The effects of the initial pH value and the distance between the electrodes on the steady shear flow behavior, structural characterization, molecular conformation, and antioxidant activity of chitosan were investigated. The results revealed that a lower initial pH value and a narrower distance between the electrodes were beneficial to the decrease in viscosity and increase in shear-thinning capacity. Structural characterization of the chitosan by FT-IR and 1H NMR showed that chemical structure of chitosan was not destroyed at different process parameters. The results of XRD, HPSEC-MALLS, SEM, and AFM indicated that SPP degradation clearly decreased the crystallinity, molecular weight, molecular size, and molecular aggregation of chitosan. At initial pH values of 2.8 and 5.8, the molecular weight was 27.16 and 44.25 kDa, at the distance between the electrodes of 4 and 8 mm, it was 35.88 and 66.17 kDa, respectively. The results of DPPH and hydroxyl radical scavenging assays demonstrated that a lower initial pH value and a narrower distance between the electrodes enhanced the antioxidant activity.

The antioxidant and antibacterial activities of chitosan extract from white shrimp shell (Penaeus indicus) in the waters north of Brebes, Indonesia

Abstract. Kusnadi, Purgiyanti, Kumoro AK, Legowo AM. 2022. The antioxidant and antibacterial activities of chitosan extract from white shrimp shell (Penaeus indicus) in the waters north of Brebes, Indonesia. Biodiversitas 23: 1267-1272. Chitosan is an oligosaccharide compound produced by deacetylation of basic chitin at high temperatures. This research aimed to extract chitosan from white shrimp (Penaeus indicus) in the waters north of Brebes, Indonesia and determine its antioxidant and antibacterial activity compared to commercial chitosan. The functional structure of chitosan was carried out through Fourier Transformation-Infrared Spectroscopy. Determination of antioxidant activity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method and its antibacterial activity was tested on Staphylococcus aureus and Escherichia coli bacterial strains. The chitosan extract was also tested for its average molecular weight. The degree of deacetylation of chitosan extract was higher 78.60% than that of commercial chitosan 73.46%. The IC50 of chitosan extract and commercial chitosan on DPPH radicals was 4.25 mg/mL and 5.2 mg/mL, respectively. The chitosan extract produced largest inhibition zone found at 1000 g/mL on S. aureus (14.40 ± 0.03 mm) and E. coli (13.78 ± 0.01 mm). The result of DPPH radical scavenging activity was directly proportional to the value of the degree of deacetylation produced by the chitosan extract from white shrimp (P. indicus), the greater the degree of deacetylation, the greater the antioxidant and antibacterial activity.

MXene (Ti3C2Tx)-Embedded Nanocomposite Hydrogels for Biomedical Applications: A Review.

Polymeric nanocomposites have been outstanding functional materials and have garnered immense attention as sustainable materials to address multi-disciplinary problems. MXenes have emerged as a newer class of 2D materials that produce metallic conductivity upon interaction with hydrophilic species, and their delamination affords monolayer nanoplatelets of a thickness of about one nm and a side size in the micrometer range. Delaminated MXene has a high aspect ratio, making it an alluring nanofiller for multifunctional polymer nanocomposites. Herein, we have classified and discussed the structure, properties and application of major polysaccharide-based electroactive hydrogels (hyaluronic acid (HA), alginate sodium (SA), chitosan (CS) and cellulose) in biomedical applications, starting with the brief historical account of MXene’s development followed by successive discussions on the synthesis methods, structures and properties of nanocomposites encompassing polysaccharides and MXenes, including their biomedical applications, cytotoxicity and biocompatibility aspects. Finally, the MXenes and their utility in the biomedical arena is deliberated with an eye on potential opportunities and challenges anticipated for them in the future, thus promoting their multifaceted applications.

3D Chitosan-Gallic Acid Complexes: Assessment of the Chemical and Biological Properties.

Three-dimensional chitosan-gallic acid complexes were proposed and prepared for the first time by a simple adsorption process of gallic acid (GA) on three-dimensional chitosan structures (3D chitosan). Highly porous 3D devices facilitate a high GA load, up to 2015 mmol/kg at pH 4.0. The preservation of the redox state of GA released from 3D chitosan was confirmed by spectroscopic analyses. The antioxidant activity of 3D chitosan-GA complexes was assessed using the DPPH radical scavenging assay and was found to be dramatically higher than that of free chitosan. The mechanical property of 3D chitosan–GA complexes was also evaluated using a compression test. Finally, 3D chitosan–GA complexes showed a significant antimicrobial capacity against E. coli and S. aureus, selected, respectively, as a model strain for Gram-negative and Gram-positive bacteria. Our study demonstrated a new, simple, and eco-friendly approach to prepare functional chitosan-based complexes for nutraceutical, cosmeceutical, and pharmaceutical applications.

PH-Induced 3D Printable Chitosan Hydrogels for Soft Actuation.

Three-dimensional (3D) printing represents a suitable technology for the development of biomimetic scaffolds for biomedical and tissue engineering applications. However, hydrogel-based inks’ printability remains a challenge due to their restricted print accuracy, mechanical properties, swelling or even cytotoxicity. Chitosan is a natural-derived polysaccharide that has arisen as a promising bioink due to its biodegradability, biocompatibility, sustainability and antibacterial properties, among others, as well as its ability to form hydrogels under the influence of a wide variety of mechanisms (thermal, ionic, pH, covalent, etc.). Its poor solubility at physiological pH, which has traditionally restricted its use, represents, on the contrary, the simplest way to induce chitosan gelation. Accordingly, herein a NaOH strong base was employed as gelling media for the direct 3D printing of chitosan structures. The obtained hydrogels were characterized in terms of morphology, chemical interactions, swelling and mechanical and rheological properties in order to evaluate the influence of the gelling solution’s ionic strength on the hydrogel characteristics. Further, the influence of printing parameters, such as extrusion speed (300, 600 and 800 mm/min) and pressure (20–35 kPa) and the cytocompatibility were also analyzed. In addition, printed gels show an electro-induced motion due to their polycationic nature, which highlights their potential as soft actuators and active scaffolds.

Physicochemical studies of the structure of chitosan and chitosan ascorbate nanoparticles

Physicochemical studies of the structure of chitosan and chitosan ascorbate nanoparticles

Modelling the mechanism and kinetics of ascorbic acid diffusion in genipin-crosslinked gelatin and chitosan networks at distinct pH

Crosslinked biopolymers were prepared for controlled release to investigate the diffusion of ascorbic acid from swelling high-solid networks in neutral and acidic pH conditions. Polymer swelling was measured at pH 2.8 and pH 6.8 and change in microstructural properties, including network mesh size and average molecular weight between crosslinks of genipin-crosslinked gelatin and genipin-crosslinked chitosan systems, were predicted. Variable mathematical modelling was applied to the first 60% of ascorbic acid diffusion and statistical analysis was used to determine the model that best fits the experimental data. Molecular transport from the gelatin-based networks was best described by the Peppas-Sahlin model whereas the distinct effect of pH on chitosan structure formation brought into consideration the zero-order model. Mathematical modelling of bioactive compound release from swelling biopolymer matrices at different pH conditions is essential for the design of efficient targeted delivery matrices for functional food and nutraceutical applications.

The Film of Chitosan-ZnO Nanoparticles-CTAB : Synthesis, Characterization and In Vitro Study

The synthesis of film chitosan- ZnO nanoparticles-CTAB were studied. The aims of this research were synthesis of the film chitosan-ZnO nanoparticles-CTAB, its characterization and, application of the film chitosan-ZnO nanoparticles-CTAB as an antibacterial of Staphylococcus aureus. The film of chitosan-ZnO nanoparticles-CTAB was synthesized by the casting method and characterized by FTIR spectroscopy and X-ray diffraction, respectively. The film of chitosan-ZnO nanoparticles-CTAB was used as an antibacterial agent with the agar disk diffusion method. The result showed that the Zn-O group at the film of chitosan-ZnO nanoparticles-CTAB was detected at a wavenumber between 578-619 cm-1. The band at 2852.72-2854.65 cm-1 is the band of C-H groups in the film of chitosan-ZnO nanoparticles-CTAB. The effect of ZnO nanoparticles-CTAB changed of the physical structure of chitosan. The average of the inhibition zone in the film of chitosan-ZnO nanoparticles-CTAB I, II and III was 10.37 ± 0.55, 11.31± 1.27 and 10.38 ± 0.24 mm respectively.

Chitosan Nanoparticle-Based System: A New Insight into the Promising Controlled Release System for Lung Cancer Treatment.

Lung cancer has been recognized as one of the most often diagnosed and perhaps most lethal cancer diseases worldwide. Conventional chemotherapy for lung cancer-related diseases has bumped into various limitations and challenges, including non-targeted drug delivery, short drug retention period, low therapeutic efficacy, and multidrug resistance (MDR). Chitosan (CS), a natural polymer derived from deacetylation of chitin, and comprised of arbitrarily distributed β-(1-4)-linked d-glucosamine (deacetylated unit) and N-acetyl-d-glucosamine (acetylated unit) that exhibits magnificent characteristics, including being mucoadhesive, biodegradable, and biocompatible, has emerged as an essential element for the development of a nano-particulate delivery vehicle. Additionally, the flexibility of CS structure due to the free protonable amino groups in the CS backbone has made it easy for the modification and functionalization of CS to be developed into a nanoparticle system with high adaptability in lung cancer treatment. In this review, the current state of chitosan nanoparticle (CNP) systems, including the advantages, challenges, and opportunities, will be discussed, followed by drug release mechanisms and mathematical kinetic models. Subsequently, various modification routes of CNP for improved and enhanced therapeutic efficacy, as well as other restrictions of conventional drug administration for lung cancer treatment, are covered.

Effect of Chitosan Deacetylation on Its Affinity to Type III Collagen: A Molecular Dynamics Study.

The ability to form strong intermolecular interactions by linear glucosamine polysaccharides with collagen is strictly related to their nonlinear dynamic behavior and hence bio-lubricating features. Type III collagen plays a crucial role in tissue regeneration, and its presence in the articular cartilage affects its bio-technical features. In this study, the molecular dynamics methodology was applied to evaluate the effect of deacetylation degree on the chitosan affinity to type III collagen. The computational procedure employed docking and geometry optimizations of different chitosan structures characterized by randomly distributed deacetylated groups. The eight different degrees of deacetylation from 12.5% to 100% were taken into account. We found an increasing linear trend (R2 = 0.97) between deacetylation degree and the collagen–chitosan interaction energy. This can be explained by replacing weak hydrophobic contacts with more stable hydrogen bonds involving amino groups in N-deacetylated chitosan moieties. In this study, the properties of chitosan were compared with hyaluronic acid, which is a natural component of synovial fluid and cartilage. As we found, when the degree of deacetylation of chitosan was greater than 0.4, it exhibited a higher affinity for collagen than in the case of hyaluronic acid.

Chitosan-based oral colon-specific delivery systems for polyphenols: recent advances and emerging trends.

Oral colon-targeted delivery systems (OCDSs) have attracted great attention in the delivery of active compounds targeted to the colon for the treatment of colon and non-colon diseases with the advantages of enhanced efficacy and reduced side effects. Chitosan, the second-most abundant biopolymer next to cellulose, has great biocompatibility, is non-toxic, is sensitive to colonic flora and shows strong adhesion to colonic mucus, making it an ideal biomaterial candidate for the construction of OCDSs. Being rich in functional groups, the chitosan structure is easily modified, both physically and chemically, for the fabrication of delivery systems with diverse geometries, including nanoparticles, microspheres/microparticles, and hydrogels, that are resistant to the harsh environment of the upper gastrointestinal tract (GIT). This review offers a detailed overview of the preparation of chitosan-based delivery systems as the basis for building OCDSs. A variety of natural polyphenols with potent biological activities are used to treat diseases of the colon, or to be metabolized as active ingredients by colonic microorganisms to intervene in remote organ diseases after absorption into the circulation. However, the poor solubility of polyphenols limits their application, and the acidic environment of the upper GIT and various enzymes in the small intestine disrupt their structure and activity. As a result, the development of OCDSs for polyphenols has become an emerging and popular area of current research in the past decade. Thus, the second objective of this review is to systematically summarize the most recent research findings in this area and shed light on the future development of chitosan-based OCDSs for nutritional and biomedical applications.

Preparation and characterization of antibacterial chitosan nanocomposites loaded with cellulose/chitosan nanofibers and essential oils

Multi-component nanocomposites based on chitosan, cellulose/chitosan nanofibers, and essential oils were developed in this study through solution casting technique. Both surface and structural properties of the nanocomposites were characterized. Surface morphology results revealed that the chitosan nanofibers were more localized at the films’ surface than the cellulose nanofibers, leading to enhanced hydrophobicity (contact angle = 95°). Moreover, the essential oils were distributed as micrometer-scale oil domains at the films’ surfaces, making them heterogeneous, leading to a much more hydrophilic character (contact angle = 30–36°). X-ray diffraction results revealed the disrupting role of nanofibers on the crystalline structure of chitosan; however, upon the addition of essential oils, the crystalline network was less affected than the pure chitosan film. The enhanced stiffness of the films in the presence of nanofibers was demonstrated by dynamic mechanical analysis. In contrast, the addition of essential oils highly reduced the stiffness, making the films much more flexible, which could benefit food packaging applications. Antibacterial properties were highly increased in the presence of essential oils, and the barrier properties were also improved, especially by the use of chitosan nanofibers. In conclusion, the developed nanofiber-loaded chitosan films could be considered innovative packaging to promote food conservation.

Effect of nanotubes on the electrical and mechanical properties of chitosan films

Using the methods of X-ray diffraction and scanning electron microscopy, the structure of composite films based on chitosan and single-wall carbon tubes has been studied. It is shown that the introduction of carbon nanotubes leads to the ordering of the chitosan structure. Increase in concentration of nanotubes (from 0 to 3%) causes rise in the value of storage modulus from 3 to 4 GPa (DMA data), increase in electrical conductivity of samples (from 10-11 to 102 S/m), and some changes in their dielectric permittivity (from 5.5. to 26 at an electrical field frequency of 1 kHz). Data on the ionic and electronic components of the conductivity of the composite film are presented. Keywords: chitosan, electrical conductivity, nanotubes, dielectric constant, composite.

Electrophysical properties of chitosan-based composite films filled with single-wall carbon nanotubes

This work focuses on new chitosan-based composite materials. In order to improve chitosan conductivity, single-wall carbon nanotubes (SWCNT) were added as a filler. The structure of the composites was studied using a scanning electron microscope. It is shown that the addition of SWNCT filler leads to chitosan structure ordering. The increase in SWCNT content from 0 wt.% to 3.0 wt.% leads to an increase in composite film conductivity from 10−11 to 10 S/m, with the relative dielectric permittivity change from 5.5 to 26 at 1 kHz. The effect of moisture on the films’ dielectric properties was also studied.

Влияние углеродных нанотрубок на электрические и механические свойства хитозановых пленок

Using the methods of X-ray diffraction and scanning electron microscopy, the structure of composite films based on chitosan and single-wall carbon tubes has been studied. It is shown that the introduction of carbon nanotubes leads to the ordering of the chitosan structure. Increase in concentration of nanotubes (from 0 to 3%) causes rise in the value of storage modulus from 3 to 4 GPa (DMA data), increase in electrical conductivity of samples (from 10-11 to 102 S/m), and some changes in their dielectric permittivity (from 5.5. to 26 at an electrical field frequency of 1kHz). Data on the ionic and electronic components of the conductivity of the composite film are presented.

Manufacturing of chitosan based drug release systems from tamarind shells for long-term and effective methylprednisolone sodium succinate release

In this study a microparticular drug delivery system containing tamarind shell and chitosan has been developed to realize the controlled release of methylprednisolone sodium succinate an important corticosteroid. Drug-loaded tamarind shells are coated with chitosan for a pH-controlled release. The release kinetics of the system have been examined in detail at three different pH ranges (3, 5 and 7.4). In our pH sensitive release systems a slow release up to 39.02%±0.81 at pH=7.4 at 72 hours. But we see that there is a faster release at 70.58±1.73% at pH=5 and 96.68±1.70% at pH=3 in 72 hours. Rapid release in acidic media depends on the solubility of the chitosan structure in acidic environments. It is believed that the pH sensitive carrier system obtained within the scope of the study will have a high potential for use in many biomedical application areas (wound surface application, etc.).

Liquid-Assisted Electrospinning Three-Dimensional Polyacrylonitrile Nanofiber Crosslinked with Chitosan

Electrospinning has become a popular nanotechnology for the fabrication of tissue engineering scaffolds, which can precisely regulate fiber diameter and microstructure. Herein, we have prepared a three-dimensional polyacrylonitrile (PAN) nanofiber by liquid-assisted electrospinning. The spacing between PAN nanofibers can reach to 15-20 μm, as the uniform internally connected pore structure can be formed, through the regulation of parameters. Furthermore, the chitosan attached to the as-prepared nanofibers gives the material antibacterial effect and increases its biocompatibility. Meanwhile, the special structure of chitosan also provides the possibility for further loading drugs in dressings in the future. This newly developed nanocomposite seems to be highly suitable for wound healing due to its unique properties of biodegradability, biocompatibility, and antimicrobial effectiveness.