Polyethylenimine (PEI) is a cationic polymer that contains repeating units composed of an amine group and a CH2CH2 spacer. Notably, PEI is an organic polymer that has the highest positive charge density potential as every third atom of this polymer is a protonable amino nitrogen. Two forms of PEI, including linear PEI and branched PEI, have been reported.

What are the use of PEI?

PEI is a simple, inexpensive and effective reagent for condensing and linking plasmid DNA to adenovirus for gene delivery. It is one of the most efficient nonviral gene delivery vectors, however its clinical application is very limited owing to the high cytotoxicity and poor heamocompatibility.

How to synthesize PEI?

PEI is synthesized by acid-catalyzed polymerization of aziridine, and yields a highly branched network with a high cationic charge-density potential. PEI is one of the most typical polycationic polymers and lysosomal-escape agents at nano size. It can be divided into linear PEI and branched PEI based on different synthesized structures. The difference between linear PEI and branched PEI is also shown by the different amino groups: linear PEI just possesses primary and secondary amino groups, whereas branched PEI also possesses tertiary amino groups. Different shaped or sized PEI presents different transfection efficiency and cytotoxicity.

What are polyethylenimine magnetic particles?

Polyethyleneimine (PEI) magnetic particles are superparamagnetic beads covalently functionalized with PEI. Absolute Mag™ PEI magnetic particles can be used with organic matrices of polystyrene polymers. PEI magnetic particles can capture negatively charged molecules, such as DNA and RNA, through charge-charge interactions.

Polyethylenimine magnetic particles for research use?

CD Bioparticles offers series of PEI Magnetic Particles for research applications, including the PEI Magnetic Particles that are water-soluble iron oxide particles with organic layers consisting of a monolayer of oleic acid, a monolayer of amphiphilic polymer, and a monolayer of polyethylenimine; and PEI Magnetic Polystyrene Particles that are magnetic polystyrene particles functionalized with PEI.

For example, Absolute Mag™ PEI Magnetic Polystyrene Particles, 2 μm (# WHM-G147) are monodisperse magnetic particles, consisting of magnetite around an organic matrix of a polystyrene polymer, and finally coated with a polymer layer for the encapsulation of magnetite. These particles are designed with a polyethylenimine coating for binding and magnetic separation of nucleic acids. They can easily be separated with a conventional permanent magnet.

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2. Kafil, V., & Omidi, Y. (2011). Cytotoxic impacts of linear and branched polyethylenimine nanostructures in a431 cells. BioImpacts: BI, 1(1), 23.
3. Rajalekshmy, G. P., Mariya, R. A., & Rekha, M. R. (2021). Pullulan-based nanomaterials in drug delivery applications. In Biopolymer-Based Nanomaterials in Drug Delivery and Biomedical Applications (pp. 383-404). Academic Press.
4. Li, Y., & Ju, D. (2017). The application, neurotoxicity, and related mechanism of cationic polymers. In Neurotoxicity of nanomaterials and nanomedicine (pp. 285-329). Academic Press.
5. Yuan, W., & Li, H. (2017). Polymer-based nanocarriers for therapeutic nucleic acids delivery. In Nanostructures for drug delivery (pp. 445-460). Elsevier.

Author's Bio: 

CD Bioparticles is a leading manufacturer of magnetic particles and related products for immunoassay development. It provides a comprehensive list of immunomagnetic bead products conjugated with different coating materials and functional groups in multiple sizes for research and industrial prospect development. Its Absolute Mag™ platform is dedicated to developing magnetic microsphere for life science applications, such as immunoprecipitation, cell isolation, RNA/DNA extraction, and protein purification.