Biocompatibility, of chitosan

Couto DS, Alves NM, Mano IF (2009) Nanostructured multilayer coatings combining chitosan with bioactive glass nanoparticles. J Nanosci Nanotech 9 1741-1748 Dong P et al (2009) Biocompatibility of chitosan/heparin multilayer coalings on NiTi. Mater Sci Forum 610-613 1179-1182... 

VandeVord et al. examined the biocompatibility of chitosan in mice. Their data imply that chitosan has a chemotactic effect on immune cells, but that effect does not lead to a humoral immune response. Also, results suggest that the specific responses reported may have been caused by contaminating proteins/polyscaccharides from the source organism. This type of contamination has been reported with other polysaccharides studied for implant use. As discussed earlier with alginates, the need to use highly purified grades of these biomaterials is critical to avoid toxicity and fibrotic encapsulation. ... 

As a biocompatible and biodegradable material, chitosan has found many and diverse medical, pharmaceutical, and therapeutic applications. Nevertheless, there is a lot of scope for improvisation in mechanical properties and biocompatibility of chitosan before it becomes an ideal biomaterial for tissue engineering applications. 

The biocompatibility of chitosan has been investigated and reported over the past several decades. A great number of studies have been performed in vitro to evaluate the biocompatibility of chitosan and chitosan-based systems using a variety of cell types such as fibroblasts [95,96], osteoblasts [97,98], chondrocytes [98], endothelial cells [34], neural cells [99], and hepatocytes [100,101]. Results have shown that chitosan is nontoxic and can support these types of cells to adhere and proliferate, which suggests that chitosan is compatible with these cell types. 

Hirano, S., Seine, H., Akiyam, Y., and Nonako, I. 1988. Biocompatibility of chitosan by oral and intravenous administration. Polymer Engineering and Science 59 897-901. 

Costa-Pinto, A. R., Martins, A. M., Castelhano-Carlos, M. J., Correlo, V. M., Sol, P. C., Longatto-Filho, A., Neves, N. M. (2014). In vitro degradation and in vivo biocompatibility of chitosan-poly (butylene succinate) fiber mesh scaffolds. (2), 137-151. 

Currently, there are still limited, incomplete, and insignificant human studies about the biocompatibility and biodegradability of newly developed chitosan derivatives. There are limited studies published in peer-reviewed journals describing the biocompatibility of chitosan or its derivatives, due to an absence of interest from manufacturers in applications of chitosan or its derivatives in the design of medical devices [104]. 

In view of the conductive and electrocatalytic features of carbon nanotubes (CNTs), AChE and choline oxidases (COx) have been covalently coimmobilized on multiwall carbon nanotubes (MWNTs) for the preparation of an organophosphorus pesticide (OP) biosensor [40, 41], Another OP biosensor has also been constructed by adsorption of AChE on MWNTs modified thick film [8], More recently AChE has been covalently linked with MWNTs doped glutaraldehyde cross-linked chitosan composite film [11], in which biopolymer chitosan provides biocompatible nature to the enzyme and MWNTs improve the conductive nature of chitosan. Even though these enzyme immobilization techniques have been reported in the last three decades, no method can be commonly used for all the enzymes by retaining their complete activity. 

Recently, other approaches and modifications of HA for gene delivery applications have been investigated. Among the most interesting ones are mixed chitosan-hyaluronan based gene delivery systems [68-70] and PEG-HA photocrosslinked hydrogels [71]. HA has also been used to improve the biocompatibility of branched PEI via covalent conjugation [72],... 

Chitin, a )5(l- 4)-linked iV-acetyl-D-glucosamine (GlcNAc) polysaccharide, is well-known for the excellent characters such as biodegradability and biocompatibility 36), Chitosan is a )ff(l- 4)-linked D-glucosamine (GlcN) polysaccharide, which is iV-deacetylated polysaccharide of chitin 41). Chitosan... 

The possibility of grafting synthetic polymer to chitosan has attracted much attention in the last years as a new way to modify the polysaccharide and develop practically useful derivatives. Graft copolymerization reactions introduce side chains and lead to the formation of novel types of tailored hybrid materials composed of natural and synthetic polymers. Grafting chitosan is a common way to improve chitosan properties such as formation of inclusion complexes [99], bacteriostatic effect [100], or to enhance adsorption properties [101, 102]. Although the grafting of chitosan modifies its properties, it is possible to retain some interesting characteristics such as mucoadhesivity [103], biocompatibility [104,105] and biodegradability [106]. 

Chitosan, a natural-based polymer obtained by alkaline deacetylation of chitin, is nontoxic, biocompatible, and biodegradable. These properties make chitosan a promising candidate for conventional and novel drug delivery systems. Because of the high affinity of chitosan for cell membranes, it has been used as a coating agent for liposome formulations [43-45]. 

---