ABSTRACT
Chitosan is a linear cationic polysaccharide, obtained by partial alkaline deacetylation of chitin, a polymer found in the exoskeleton of crustaceans. Chitosans are biodegradable and biocompatible polymers and thus can be potentially safe and nontoxic carriers for gene delivery. In general, gene delivery/expression vectors can be broadly categorized into the viral and nonviral vectors. Viral vectors include the use of genetically engineered retroviruses, adenoviruses, adeno-associated viruses, and other viruses that have been used for gene-transfer procedures. The high density of amino groups present in the glucosamine backbone of chitosan can be protonated and thus offers the opportunity to complex chitosans with negatively charged deoxyribonucleic acid (DNA) molecules, owing to the electrostatic interactions. Nanoparticles (NPs) for gene delivery can be prepared by complexing plasmid DNA with chitosan or by encapsulating DNA inside chitosan NPs. Magnetic NPs usually incorporate magnetic-responsive materials such as magnetite, iron, nickel, cobalt, and so on.
