Stimuli-Responsive Structures from Cationic Polymers for Biomedical Applications

Stimuli-Responsive Structures from Cationic Polymers for Biomedical Applications 

Box 1033 Blindern, N-0315 Oslo, Norway Email bo.nystrom(f)kjemi.uio.no 

Cationic polymers are defined as polyelectrolytes cariying positive charges, and they are either derived from natural sources such as chitosan, or chemically synthesized where the charges have been incorporated on their backbone and/or side chains. They may also exist as block copolymers, where one of the blocks is decorated with positive charges. When these block copolymers consist of a hydrophobic block, they readily undergo self-assembly in aqueous solutions and form micellar structures with a positively charged surface. Similarly, if the block copolymer consists of two hydrophobic blocks, one at each end, the system may self-assemble into network structures called hydrogels, which are water-rich 3D interconnected networks. 

The aim of this chapter is to give a brief selective overview of typical biomedical areas where cationic polymers can be employed. The use of cationic polymers in tissue engineering is a high priority topic in this chapter and several aspects on this phenomenon are given related to this is the potential of cationic hydrogels for medical and pharmaceutical applications. The importance of cationic polymers and copolymers as non-viral vectors in gene therapy is described, as well as how micelles and vesicles based on cationic polypeptides can form nanostructures by self-assembly. The potential of cationic polymers for drug delivery applications is also elucidated. 

Illustration of the main concepts of tissue engineering. The developed scaffolds are seeded with the cells. The cells are then allowed to proliferate in vitro in the presence of hioactive molecules. The fully developed tissue can finally be transplanted to the regeneration site. 

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