Biomaterials Based on Chitosan and Its Derivatives and Their Potential in Tissue Engineering and Other Biomedical Applications-A Review

Chitosan-Alginate Gels for Sorption of Hazardous Materials: The Effect of Chemical Composition and Physical State

Chitosan, alginate, and chitosan-alginate (50:50) mixed hydrogels were prepared by freeze casting, freeze-drying, and subsequent physical cross-linking. Chitosan was cross-linked with citrate and alginate with calcium ions, while the mixed gels were cross-linked with both cross-linking agents. Both cryogels and xerogels were obtained by lyophilization and drying of the hydrogels. We investigated the effect of the chemical composition and the physical state of gels on the gel structure and sorption of model dyes. Alginate and mixed gels cross-linked with Ca2+ ions sorbed 80-95% of cationic dye from the solutions. The chitosan gels are primarily capable of adsorbing anionic dyes, but at near-neutral pH, their capacity is lower than that of alginate gels, showing 50-60% dye sorption. In the case of alginate gels, the dye sorption capacity of xerogels, cryogels, and hydrogels was the same, but for chitosan gels, the hydrogels adsorbed slightly less dye than the dried gels.

Swelling, Protein Adsorption, and Biocompatibility of Pectin-Chitosan Hydrogels

The study aims to determine how chitosan impacts pectin hydrogel's ability to attach peritoneal leukocytes, activate complement, induce hemolysis, and adsorb blood proteins. The hydrogels PEC-Chi0, PEC-Chi25, PEC-Chi50, and PEC-Chi75 were prepared by placing a mixture solution of 4% pectin and 4% chitosan in a ratio of 4:0, 3:1, 2:2, and 1:3 in a solution of 1.0 M CaCl2. Chitosan was found to modify the mechanical properties of pectin-calcium hydrogels, such as hardness and cohesiveness-to-adhesiveness ratio. Chitosan in the pectin-calcium hydrogel caused pH-sensitive swelling in Hanks' solution. The PEC-Chi75 hydrogel was shown to adsorb serum proteins at pH 7.4 to a greater extent than other hydrogels. PEC-Chi75's strong adsorption capacity was related to lower peritoneal leukocyte adherence to its surface when compared to other hydrogels, showing improved biocompatibility. Using the optical tweezers approach, it was shown that the force of interaction between pectin-chitosan hydrogels and plasma proteins increased from 10 to 24 pN with increasing chitosan content from 0 to 75%. Thus, the properties of pectin-calcium hydrogel, which determine interactions with body tissues after implantation, are improved by the addition of chitosan, making pectin-chitosan hydrogel a promising candidate for smart biomaterial development.

Injectable Double Crosslinked Hydrogel-Polypropylene Composite Mesh for Repairing Full-Thickness Abdominal Wall Defects

Abdominal wall defects are common clinical diseases, and mesh repair is the standard treatment method. The most commonly used polypropylene (PP) mesh in clinical practice has the advantages of good mechanical properties, stable performance, and effective tissue integration effect. However, direct contact between abdominal viscera and PP mesh can lead to severe abdominal adhesions. To prevent this, the development of a hydrogel-PP composite mesh with anti-adhesive properties may be an effective measure. Herein, biofunctional hydrogel loaded with rosmarinic acid is developed by modifying chitosan and Pluronic F127, which possesses suitable physical and chemical properties and commendable in vitro biocompatibility. In the repair of full-thickness abdominal wall defects in rats, hydrogels are injected onto the surface of PP mesh and applied to intraperitoneal repair. The results indicate that the use of hydrogel-PP composite mesh can alleviate abdominal adhesions resulting from traditional PP mesh implantation by decreasing local inflammatory response, reducing oxidative stress, and regulating the fibrinolytic system. Combined with the tissue integration ability of PP mesh, hydrogel-PP composite mesh has great potential for repairing full-thickness abdominal wall defects.

Potency of the Combination of Chitosan and Hydroxyapatite on Angiogenesis and Fibroblast Cell Proliferation in Direct Pulp Capping of Rattus norvegicus

OBJECTIVES

 The aim of this research was to analyze expression of vascular endothelial growth factor (VEGF), blood vessels, and fibroblast cell proliferation in direct pulp capping treatment of Rattus norvegicus using a combination of chitosan and hydroxyapatite paste.

MATERIALS AND METHODS

 The samples were male R. norvegicus strains of Wistar rats, weighing 200 to 250 g and aged between 8 and 16 weeks. The occlusal surface of the molars of R. norvegicus was prepared with class I cavity and then perforated with the tip of an explorer. Sixty male R. Norvegicus rats were divided into the following: control group (KA) in which the cavity was filled with glass ionomer cement; control group (KB), in which the cavity was filled with Ca(OH)2; PA group, in which the cavity was filled with chitosan (CH); PB group, in which the cavity was filled with hydroxyapatite (HA); and PC group, in which the cavity was filled with chitosan and hydroxyapatite (CH-HA). Each group was divided into 3-, 7-, and 14-day observation groups. The mandibular bone of the molar was cut and histopathological examination was performed to analyze the blood vessels and fibroblast cell proliferation. Immunohistochemistry examination was done to examine the expression of VEGF.

STATISTICAL ANALYSIS

The data variation was analyzed with One Way Analysis of Variance (ANOVA) test and continued with multiple comparison Least Significant (LSD) test to determine the different pairs of group.

RESULTS

 Analysis of variance (ANOVA) showed a significant increase in the expression of VEGF, blood vessels, and fibroblast cell proliferations (p ≤ 0.05;), especially in the PC group compared to the other four groups. The least significant test (LSD) test showed significant differences between the groups on the expression of VEGF, blood vessels, and fibroblast cell proliferations.

CONCLUSION

 The combination of chitosan and hydroxyapatite could promote healing of direct pulp capping treatment by increasing the expression of VEGF, blood vessel, and fibroblast cell proliferation.

Pharmaceutical applications of chitosan in skin regeneration: A review

Skin regeneration is the process that restores damaged tissues. When the body experiences trauma or surgical incisions, the skin and tissues on the wound surface become damaged. The body repairs this damage through complex physiological processes to restore the original structural and functional states of the affected tissues. Chitosan, a degradable natural bioactive polysaccharide, has attracted widespread attention partly owing to its excellent biocompatibility and antimicrobial properties; additionally, a modified form of this compound has been shown to promote skin regeneration. This review evaluates the recent research progress in the application of chitosan to promote skin regeneration. First, we discuss the basic principles of the extraction and preparation processes of chitosan from its source. Subsequently, we describe the functional properties of chitosan and the optimization of these properties through modification. We then focus on the existing chitosan-based biomaterials developed for clinical applications and their corresponding effects on skin regeneration, particularly in cases of diabetic and burn wounds. Finally, we explore the challenges and prospects associated with the use of chitosan in skin regeneration. Overall, this review provides a reference for related research and contributes to the further development of chitosan-based products in cutaneous skin regeneration.

Advances in chitosan and chitosan derivatives for biomedical applications in tissue engineering: An updated review

In recent years, chitosan (CS) has received much attention as a functional biopolymer for various applications, especially in the biomedical field. It is a natural polysaccharide created by the chemical deacetylation of chitin (CT) that is nontoxic, biocompatible, and biodegradable. This natural polymer is difficult to process; however, chemical modification of the CS backbone allows improved use of functional derivatives. CS and its derivatives are used to prepare hydrogels, membranes, scaffolds, fibers, foams, and sponges, primarily for regenerative medicine. Tissue engineering (TE), currently one of the fastest-growing fields in the life sciences, primarily aims to restore or replace lost or damaged organs and tissues using supports that, combined with cells and biomolecules, generate new tissue. In this sense, the growing interest in the application of biomaterials based on CS and some of its derivatives is justifiable. This review aims to summarize the most important recent advances in developing biomaterials based on CS and its derivatives and to study their synthesis, characterization, and applications in the biomedical field, especially in the TE area.

The 3-dimensional printing for dental tissue regeneration: the state of the art and future challenges

Tooth loss or damage poses great threaten to oral and general health. While contemporary clinical treatments have enabled tooth restoration to a certain extent, achieving functional tooth regeneration remains a challenging task due to the intricate and hierarchically organized architecture of teeth. The past few decades have seen a rapid development of three-dimensional (3D) printing technology, which has provided new breakthroughs in the field of tissue engineering and regenerative dentistry. This review outlined the bioactive materials and stem/progenitor cells used in dental regeneration, summarized recent advancements in the application of 3D printing technology for tooth and tooth-supporting tissue regeneration, including dental pulp, dentin, periodontal ligament, alveolar bone and so on. It also discussed current obstacles and potential future directions, aiming to inspire innovative ideas and encourage further development in regenerative medicine.

QbD-Based Fabrication of Biomimetic Hydroxyapatite Embedded Gelatin Nanoparticles for Localized Drug Delivery against Deteriorated Arthritic Joint Architecture

Biomaterials such as nanohydroxyapatite and gelatin are widely explored to improve damaged joint architecture associated with rheumatoid arthritis (RA). Besides joint damage, RA is associated with inflammation of joints and cartilage, which potentiates the need for both bone nucleation and therapeutic intervention. For such purpose, a modified nanoprecipitation method is used herein to fabricate tofacitinib (Tofa)-loaded nanohydroxyapatite (nHA) embedded gelatin (GLT) nanoparticles (NPs) (Tofa-nHA-GLT NPs). The quality by design (QbD) approach is chosen to assess the key parameters that determine the efficiency of the NPs, and are further optimized via Box-Behnken design of experiment. The particle size, polydispersity, zeta potential, and encapsulation efficiency (EE) of the prepared NPs are found to be 269 nm, 0.18, -20.5 mV, and 90.7%, respectively. Furthermore, the NPs have improved stability, skin permeability, and a sustained drug release pattern at pH 6.5 (arthritic joint pH). Moreover, rhodamine-B loaded nHA-GLT NPs demonstrates considerably higher cellular uptake by the murine-derived macrophages than free rhodamine-B solution. In vitro, cell-based experiments confirm the good cell biocompatibility with insignificant toxicity. Thus, QbD-based approach has successfully led to the development of Tofa-nHA-GLT NPs with the potential to target inflamed arthritic joint.

Trimethylated chitosan-coated flexible liposomes with resveratrol for topical drug delivery to reduce blue-light-induced retinal damage

LED-related blue-light-induced damage can cause eye diseases. However, drug delivery in patients with ocular diseases is faced with various challenges. In this study, we developed flexible liposomes based on trimethylated chitosan (TMC-Lipo) to deliver resveratrol for the treatment of retinal diseases. Flexible liposomes can easily cross various biological barriers. Chitosan and its derivatives have adhesive properties and are widely used in mucoadhesive drug delivery systems. Therefore, we wrapped flexible liposomes with trimethylated chitosan via electrostatic adsorption. The charge of the flexible liposomes became positive after encapsulation in TMC, and they remained stable in artificial tears. We assessed the safety of TMC-Lipo in cellular and zebrafish experiments and found that it can be safely used. In addition, treatment with TMC-Lipo significantly reduced H2O2-induced damage to ARPE-19 cells, restored mitochondrial membrane potential, and protected the cells. TMC-Lipo more easily reached the posterior ocular segment of the mice than liposome nanoparticles and attenuated blue-light-induced retinal cytopathy. Our study demonstrates that effective eye drop formulations can be developed based on trimethylated chitosan, which provides a promising approach for the treatment of ocular diseases.

Physical Properties and Release Profiles of Chitosan Mixture Films Containing Salicin, Glycerin and Hyaluronic Acid

Chitosan (CS) has gained considerable attention due to its distinctive properties and its broad spectrum of potential applications, spanning cosmetics, pharmaceuticals, and biomedical uses. In this study, we characterized thin films comprising chitosan mixtures containing salicin (SAL) and glycerin (GLY), both with and without hyaluronic acid (HA) as active ingredients. Characterization was achieved through release studies of SAL, infrared spectroscopy, microscopy techniques (AFM and SEM), and thermogravimetric analysis (TGA). CS/GLY/SAL and CS/GLY/SAL/HA mixture films were fabricated using the solvent evaporation technique. We probed interactions between the components in the chitosan mixtures via infrared analysis. The concentration of released salicin was monitored at various time intervals in a phosphate buffer (PBS) at pH 5.5 using HPLC. The linear regression analysis for the calibration graph showed a good linear relationship (R2 = 0.9996) in the working concentration range of 5-205 mg/dm3. Notably, the release of SAL reached its peak after 20 min. Furthermore, the introduction of HA caused changes in the films' morphology, but their roughness remained largely unchanged. The results obtained were compared, indicating that the release of SAL in the CS mixture films is sufficient for diverse applications, including wound-healing materials and cosmetic beauty masks.

Biological Materials for Tissue-Engineered Vascular Grafts: Overview of Recent Advancements

The clinical demand for tissue-engineered vascular grafts is still rising, and there are many challenges that need to be overcome, in particular, to obtain functional small-diameter grafts. The many advances made in cell culture, biomaterials, manufacturing techniques, and tissue engineering methods have led to various promising solutions for vascular graft production, with available options able to recapitulate both biological and mechanical properties of native blood vessels. Due to the rising interest in materials with bioactive potentials, materials from natural sources have also recently gained more attention for vascular tissue engineering, and new strategies have been developed to solve the disadvantages related to their use. In this review, the progress made in tissue-engineered vascular graft production is discussed. We highlight, in particular, the use of natural materials as scaffolds for vascular tissue engineering.

Preparation of caffeic acid grafted chitosan self-assembled micelles to enhance oral bioavailability and antibacterial activity of quercetin

Quercetin (QR) is a naturally occurring flavonoid organic compound that has poor solubility in water and highly unstable in alkaline conditions, resulting in limited absorption in poultry. Consequently, in our experiment, QR was employed as a model compound, encapsulated within the caffeic acid graft chitosan copolymer (CA-g-CS) self-assembled micelles to enhance its solubility, stability and exhibit a synergistic antibacterial effect. The optimization of the formula was carried out using a combination of single-factor experimentation and the response surface method. The in vitro release rate and stability of CA-g-CS-loaded QR micelles (CA-g-CS/QR) in various pH media were studied and the pharmacokinetics in white feather broiler chickens was evaluated in vivo. Additionally, the antibacterial activity was investigated using Escherichia coliCMCC44102 and Escherichia coli of chicken origin as the test strain. The results showed the optimized formula for the self-assembled micelles were 4 mL water, 0.02 mg/mL graft copolymer, and 1 mg QR, stirring at room temperature. The encapsulation efficiency was 72.09%. The resulting CA-g-CS/QR was uniform in size with an average diameter of 375.6 ± 5.9 nm. The release pattern was consistent with the Ritger-Peppas model. CA-g-CS/QR also significantly improved the stability of QR in alkaline condition. The relative bioavailability of CA-g-CS/QR was found to be 1.67-fold that of the reference drug, indicating a substantial increase in the absorption of QR in the broiler. Compared to the original drug, the antibacterial activity of CA-g-CS/QR was significantly enhanced, as evidenced by a reduction of half in the MIC and MBC values. These results suggest that CA-g-CS/QR improves the bioavailability and antibacterial activity of QR, making it a promising candidate for clinical use.

Effect of Chitosan on Rheological, Mechanical, and Adhesive Properties of Pectin-Calcium Gel

In the present study, chitosan was included in the pectin ionotropic gel to improve its mechanical and bioadhesive properties. Pectin-chitosan gels P-Ch0, P-Ch1, P-Ch2, and P-Ch3 of chitosan weight fractions of 0.00, 0.25, 0.50, and 0.75 were prepared and characterized by dynamic rheological tests, penetration tests, and serosal adhesion ex vivo assays. The storage modulus (G') and loss modulus (G″) values, gel hardness, and elasticity of P-Ch1 were significantly higher than those of P-Ch0 gel. However, a further increase in the content of chitosan in the gel significantly reduced these parameters. The inclusion of chitosan into the pectin gel led to a decrease in weight and an increase in hardness during incubation in Hanks' solution at pH 5.0, 7.4, and 8.0. The adhesion of P-Ch1 and P-Ch2 to rat intestinal serosa ex vivo was 1.3 and 1.7 times stronger, whereas that of P-Ch3 was similar to that of a P-Ch0 gel. Pre-incubation in Hanks' solution at pH 5.0 and 7.4 reduced the adhesivity of gels; however, the adhesivity of P-Ch1 and P-Ch2 exceeded that of P-Ch0 and P-Ch3. Thus, serosal adhesion combined with higher mechanical stability in a wide pH range appeared to be advantages of the inclusion of chitosan into pectin gel.

Quaternized chitosan (nano)fibers: A journey from preparation to high performance applications

The industrial production of chitosan, initiated over 50 years ago, has transformed its application across diverse industries, agriculture, and medicine. To enhance its properties, numerous chitosan derivatives have been synthesized. The quaternization of chitosan has proven beneficial, as it not only enhances its properties but also imparts water solubility, expanding its potential for a wider range of applications. Specifically, the utilization of quaternized chitosan-based nanofibers has leveraged the synergistic benefits of quaternized chitosan (including hydrophilicity, bioadhesiveness, antimicrobial, antioxidant, hemostatic, and antiviral activities, as well as ionic conductivity) in combination with the distinctive characteristics of nanofibers (such as a high aspect ratio and 3D architecture). This combination has permitted numerous possibilities, spanning from wound dressings, air and water filters, drug delivery scaffolds, antimicrobial textiles, to energy storage systems and alkaline fuel cells. In this comprehensive review, we examine the preparation methods, properties, and applications of various composite fibers containing quaternized chitosan. The advantages and disadvantages of each method and composition are meticulously summarized, while relevant diagrams and figures illustrate the key findings.

Current advancements in bio-ink technology for cartilage and bone tissue engineering

In tissue engineering, the fate of a particular organ/tissue regeneration and repair mainly depends on three pillars - 3D architecture, cells used, and stimulus provided. 3D cell supportive structure development is one of the crucial pillars necessary for defining organ/tissue geometry and shape. In recent years, the advancements in 3D bio-printing (additive manufacturing) made it possible to develop very precise 3D architectures with the help of industrial software like Computer-Aided Design (CAD). The main requirement for the 3D printing process is the bio-ink, which can act as a source for cell support, proliferation, drug (growth factors, stimulators) delivery, and organ/tissue shape. The selection of the bio-ink depends upon the type of 3D tissue of interest. Printing tissues like bone and cartilage is always challenging because it is difficult to find printable biomaterial that can act as bio-ink and mimic the strength of the natural bone and cartilage tissues. This review describes different biomaterials used to develop bio-inks with different processing variables and cell-seeding densities for bone and cartilage 3D printing applications. The review also discusses the advantages, limitations, and cell bio-ink compatibility in each biomaterial section. The emphasis is given to bio-inks reported for 3D printing cartilage and bone and their applications in orthopedics and orthodontists. The critical/important performance and the architectural morphology requirements of desired bone and cartilage bio-inks were compiled in summary.

Cell Adhesion and Initial Bone Matrix Deposition on Titanium-Based Implants with Chitosan-Collagen Coatings: An In Vitro Study

In orthopedics, titanium (Ti)-alloy implants, are often considered as the first-choice candidates for bone tissue engineering. An appropriate implant coating enhances bone matrix ingrowth and biocompatibility, improving osseointegration. Collagen I (COLL) and chitosan (CS) are largely employed in several different medical applications, for their antibacterial and osteogenic properties. This is the first in vitro study that provides a preliminary comparison between two combinations of COLL/CS coverings for Ti-alloy implants, in terms of cell adhesion, viability, and bone matrix production for probable future use as a bone implant. Through an innovative spraying technique, COLL-CS-COLL and CS-COLL-CS coverings were applied over Ti-alloy (Ti-POR) cylinders. After cytotoxicity evaluations, human bone marrow mesenchymal stem cells (hBMSCs) were seeded onto specimens for 28 days. Cell viability, gene expression, histology, and scanning electron microscopy evaluations were performed. No cytotoxic effects were observed. All cylinders were biocompatible, thus permitting hBMSCs' proliferation. Furthermore, an initial bone matrix deposition was observed, especially in the presence of the two coatings. Neither of the coatings used interferes with the osteogenic differentiation process of hBMSCs, or with an initial deposition of new bone matrix. This study sets the stage for future, more complex, ex vivo or in vivo studies.

Conjugates of Chitosan with β-Cyclodextrins as Promising Carriers for the Delivery of Levofloxacin: Spectral and Microbiological Studies

In this work, we synthesized chitosan 5 kDa conjugates with β-cyclodextrins with various substituents as promising mucoadhesive carriers for the delivery of fluoroquinolones using the example of levofloxacin. The obtained conjugates were comprehensively characterized by spectral methods (UV-Vis, ATR-FTIR, 1H NMR, SEM). The physico-chemical properties of the complex formations were studied by IR, UV, and fluorescence spectroscopy. The dissociation constants of complexes with levofloxacin were determined. Complexation with conjugates provided four times slower drug release in comparison with plain CD and more than 20 times in comparison with the free drug. The antibacterial activity of the complexes was tested on model microorganisms Gram-negative bacteria Escherichia coli ATCC 25922 and Gram-positive Bacillus subtilis ATCC 6633. The complex with the conjugate demonstrated the same initial levofloxacin antibacterial activity but provided significant benefits, e.g., prolonged release.