(4f) Zwitterionic/Mixed Charge Polymers as Next-Generation Biomaterials

We have demonstrated a class of ?stealth? zwitterionic materials that are highly resistant to nonspecific protein adsorption, bacterial adhesion, and biofilm formation. Among zwitterionic materials, poly(carboxybetaine) (PCB) can be uniquely functionalized by biomolecules. PCB-coated nanoparticles (NPs) are ideal for targeted therapeutics and diagnostics with long circulation time. Cationic ester derivatives of PCB are developed for gene delivery with high efficacy and low toxicity. Those derivatives also enable the attachment of super-hydrophilic PCB to hydrophobic moieties, resulting in amphiphilic polymers with the sharp hydrophobic/hydrophilic contrast between two moieties. Bio-degradable NPs and liposomes assembled from those amphiphilic polymers exhibit unusual properties that are not found in any current NP systems including polyethylene glycol (PEG) modified NPs. Similar to zwitterionic materials, it has been demonstrated that mixed-charge materials such as natural peptides with alternating charges are also ?stealthy?.