6.4.4. Polyzwitterions

Polyzwitterions are a class of polymers consisting of zwitterionic moieties (anionic and cationic groups) as monomers. Poly(sulfobetaines), poly(carbobetaines), and poly(phosphobetaines) are representatives of a special class of polyzwitterions [163]. Gromadzki et al. (2017) developed a core-shell nanocapsule consisting of a dimer fatty acid-based aliphatic polyester core and zwitterionic poly(sulfobetaine) shell for the controlled delivery of curcumin, obtaining nanoparticles of <100 nm in size with an encapsulation e fficiency of 98%. The researchers evaluated free and encapsulated curcumin for cytotoxicity and antioxidant activity in a panel of human cell lines and rat liver microsomes, respectively. Encapsulated curcumin had superior cytotoxic and antioxidant activity versus the free drug. In addition, cell viability experiments with non-loaded nanoparticles, both coated and noncoated, demonstrated that the developed nanoparticles are nontoxic, making them potentially suitable candidates for systemic passive targeting in cancer therapy, namely for the treatment of solid tumors exhibiting a high tumor accumulation of the capsules due to enhanced permeability and retention e ffects [164].
