Polyethylenimine, branched

Polyethylenimine (PEI) is a hydrophilic cationic polymer widely used as a nonviral nucleotide delivery reagent. Branched PEI can be synthesized by cationic ring-opening polymerization of aziridine. PEI-based particles can also be used as adjuvants for vaccines. Owing to its excellent physicochemical properties, it is applied in many fields like the separation and purification of proteins, carbon dioxide absorption, drug carriers, effluent treatment, and biological labels.

Polyethyleneimine can be used as a non-viral synthetic polymer vector for in vivo delivery of therapeutic nucleic acids. The interaction between negatively charged nucleic acids and positively charged polymer backbone results in the formation of nano-sized complexes. This neutralized complex protects the enclosed nucleic acid from enzymes and maintains its stability till the cellular uptake takes place. For example, human serum albumin conjugated PEI shows good pDNA transfection and low toxicity.

PEI can be used to functionalize single-walled nanotubes (SWNTs) to improve their solubility and biocompatibility while maintaining the structural integrity of the original SWNT. Covalently functionalized SWNTs find application in CO₂ absorption and gene delivery.

Branched PEI can also be used to modify the surface properties of adsorbents. PEI-modified hydrous zirconium oxide/PAN nanofibers are used for the defluorination of groundwater as they show high fluoride adsorption capacity and a wide working pH range.

Primary and secondary amine groups of PEI can efficiently bind to drugs, nucleic acids, and other functional moieties.

Branched PEI has better complexation andbuffering capacity.

Branched polymer