Chitosan is a linear, semi-crystalline natural polysaccharide derived from chitin and is found mainly in the cell walls of crustaceans and fungi. Chitosan is insoluble in water and most organic solvents, but soluble in dilute acids, turning the protonated amino groups into polycations, which can form ionic complexes with a variety of natural or synthetic anions or polymers, such as DNA, proteins, lipids, polyacrylic acid, etc. Chitosan has excellent biological properties, including good biosafety, mucoadhesion, blood compatibility, biodegradability, etc, and has antioxidant and antibacterial properties. In the field of biomedicine, chitosan initially entered clinical research as a hemostatic dressing. In recent years, based on its excellent drug-loading properties and excellent bone conductivity, more and more researchers have used chitosan. For constructing drug delivery systems and tissue engineering scaffolds. In addition, by chemically modifying chitosan and introducing functional groups to form chitosan derivatives, certain aspects of its characteristics can be further improved to meet research needs. Common chitosan derivatives include acylated chitosan, carboxylated chitosan, alkylated chitosan, quaternized chitosan, etc.
Figure 1. Overview of production and structure of chitosan. (Bailei Li, et al., 2020)
Chitosan can be processed into films, hydrogels, fibers, microspheres, nanoparticles and other forms, and has unique mucoadhesion and penetration enhancement properties. These properties make chitosan an ideal drug delivery material. In recent years, chitosan self-assembled nanoparticles have become popular as a more advanced delivery system. Chitosan has self-assembly properties and is superior to currently common nanoparticles delivery systemin terms of biocompatibility, degradability, and safety. Research has found that this delivery system has achieved ideal delivery effects through multiple administration routes such as the oral cavity, mucous membranes, and skin. Chitosan has bacteriostatic, bactericidal, hemostatic, anti-ulcer, anti-inflammatory, antioxidant, anti-diabetic and neuroprotective effects. Its structure is similar to collagen and can be used to simulate extracellular matrix. Chitosan-based drug delivery systems can be used for the delivery of proteins/peptides, growth factors, anti-inflammatory drugs, antibiotics, anti-cancer drugs, vaccines, etc., and can also be used for gene therapy. An important feature of chitosan is its strong adhesive force, which is due to electrostatic interactions between the positively charged amino groups on the polymer chains and the negatively charged mucin residues rich in sialic and sulfonic acids. Chitosan-based nanocarriers have the advantages of small size, large specific surface area, and good adhesion properties. They can promote the entry of drugs into cells, enhance drug stability, achieve controlled release, sustained release of drugs, or reduce drug cytotoxicity. Chitosan, whether used alone or as a composite material, is suitable for preparing different types of drug-loaded preparations, such as nanoparticles, hydrogels, composite materials, microspheres, wound materials, etc. In addition, chitosan-based drug carriers have sustained and controlled release effects, which indirectly improves drug efficacy. They also have targeting properties and improved adhesion capabilities.
In addition, chitosan is widely used in bone tissue engineering as an excellent scaffold material based on its good biocompatibility and osteoconductivity. On the one hand, chitosan can be combined with other materials to make chitosan composite scaffold materials to improve its mechanical properties. At the same time, incorporating bioactive molecules into the composite scaffold can accelerate bone regeneration and enhance new blood vessel formation in the body. On the other hand, chitosan and its composite materials can be used as surface modifiers for treating bone implants and synthetic scaffolds to enhance bioactivity and improve osteogenic potential. In addition, chitosan can also depolymerize and release chitosan monomers, which activates the mitogen-activated protein kinase (MAPK) cascade reaction through signal transduction at the mRNA level and activates osteoblasts. Chitosan-based materials not only have good biocompatibility and biodegradability, but also have excellent properties such as being able to form different structures and combine with a variety of bioactive materials, making them ideal bioactive materials. At present, chitosan-based tissue engineering materials are mainly used in cartilage tissue engineering, bone tissue engineering, intervertebral disc tissue engineering, vascular tissue engineering, corneal regeneration, skin tissue engineering, periodontal tissue engineering, etc. The application of chitosan-based tissue engineering materials in tissues and organs such as skin, blood vessels, corneas, bones, etc. heralds its application prospects in repair, fixation and regeneration.
Alternate Names:
Deacetylated chitin
Chitin oligosaccharide
Chitin derivative
Chitosan oligomer
N-deacetylated chitosan
References:
1. Bailei Li, et al., Recent Advancement of Molecular Structure and Biomaterial Function of Chitosan from Marine Organisms for Pharmaceutical and Nutraceutical Application. Appl. Sci. 2020, 10(14), 4719.
Chitosan-Based Nanoparticles as Effective Drug Delivery Systems-A review
Molecules
Authors: Jafernik K, Ładniak A, Blicharska E, Czarnek K, Ekiert H, Wiącek AE, Szopa A.
Abstract
Chitosan-based nanoparticles (chitosan-based nanocomposites; chitosan nanoparticles; ChNPs) are promising materials that are receiving a lot of attention in the last decades. ChNPs have great potential as nanocarriers. They are able to encapsulate drugs as well as active compounds and deliver them to a specific place in the body providing a controlled release. In the article, an overview has been made of the most frequently used preparation methods, and the developed applications in medicine. The presentation of the most important information concerning ChNPs, especially chitosan's properties in drug delivery systems (DDS), as well as the method of NPs production was quoted. Additionally, the specification and classification of the NPs' morphological features determined their application together with the methods of attaching drugs to NPs. The latest scientific reports of the DDS using ChNPs administered orally, through the eye, on the skin and transdermally were taken into account.
Chitosan Nanomedicine in Cancer Therapy: Targeted Delivery and Cellular Uptake
Macromol Biosci
Authors: Mushtaq A, Li L, A A, Grøndahl L.
Abstract
Nanomedicine has gained much attention for the management and treatment of cancers due to the distinctive physicochemical properties of the drug-loaded particles. Chitosan's cationic nature is attractive for the development of such particles for drug delivery, transfection, and controlled release. The particle properties can be improved by modification of the polymer or the particle themselves. The physicochemical properties of chitosan particles are analyzed in 126 recent studies, which allows to highlight their impact on passive and active targeted drug delivery, cellular uptake, and tumor growth inhibition (TGI). From 2012 to 2019, out of 40 in vivo studies, only 4 studies are found reporting a reduction in tumor size by using chitosan particles while all other studies reported tumor growth inhibition relative to controls. A total of 23 studies are analyzed for cellular uptake including 12 studies reporting cellular uptake mechanisms. Understanding and exploiting the processes involved in targeted delivery, endocytosis, and exocytosis by controlling the physicochemical properties of chitosan particles are important for the development of safe and efficient nanomedicine. It is concluded based on the recent literature available on chitosan particles that combination therapies can play a pivotal role in transformation of chitosan nanomedicine from bench to bedside.
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