Drug Delivery Nanoparticles Modified by Zwitterionic Polymers

Zwitterionic polymers such as poly(carboxybetaine) (PCB) have shown excellent stealth and functioanlization properties and are potential alternatives to poly(ethylene glycol) (PEG) for a broad range of applications due to the instability of PEG. However, it is very difficult to combine PCB to any hydrophobic domains due to its super-hydrophilic property. This work introduces a generic method to covalently attach super-hydrophilic PCB to hydrophobic moieties by adopting the hydrolysable hydrophobic precursor of zwitterionic PCB. Base on this method, poly(lactic-co-glycolic acid) (PLGA)-PCB block copolymers were synthesized. We further demonstrate that drug delivery nanoparticles (NPs) assembled from such “sharp contrast” macromolecules exhibit unusual properties that are not found in any of current NP systems. Other types of NPs modified by PCB will also be discussed.