Scaffolding natural biopolymers

Chitosan is a natural biopolymer that has many desirable characteristics as a scaffold or encapsulation material. It is a biodegradable, semicrystalline polysaccharide obtained by A-deacetylation of chitin, which is harvested from the exoskeleton of marine crustaceans. Chitosan is composed of glucosamine and A-acetyl glucosamine which are linked by glycosidic bonds. Being structurally similar to ECM components, chitosan provides cell-ECM interactions which guide cell behavior. 

Differences in the fluorescent intensities upon induction of conformational changes are observed in the case of fluorescently labeled biopolymers such as protein or DNA, though these scaffolds have not been extensively used so far for the synthesis of enantioselective luminescent sensors. An advantage of using these natural scaffolds is that high enantiomeric recognition is one of their intrinsic properties [141]. 

Due to its hydrophiUcity and cationic nature, chitosan has been investigated as a drug delivery vehicle for the targeted delivery of chemotherapeutics, antibiotics, as weU as DNA and proteins. The ability to form porous matrices makes chitosan an attractive material for use as a tissue engineering scaffold. Chitosan and its family of composites with other biopolymers has been fabricated into fibrous materials for use as tissue engineering scaffolds for the regeneration of bone, ligaments, tendons, nerve, and skin [57]. 

Amino acid and amino ester bearing polymers are useful models of the naturally occurring proteins and peptides, in which the nature and sequence of the monomer units determine the biological activity of the resulting polymer [20]. Thus, by choosing suitable monomers, simple mimics of biopolymers could be obtained. Moreover, since the amino acid and amino ester moieties are hydrolytically unstable, many drugs can be linked to the polymer scaffold by this type of linkages [10]. 

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