Polyethylenimine, linear
Product Details
Linear Polyethylenamine (L-PEI) is a high-charge cationic polymer with a well-defined linear structure and high charge density. It is particularly useful in gene delivery and cell culture applications. Its properties can be tailored by controlling its molecular weight during synthesis.
TDA’s LPEI has a higher hydrolysis percentage than other branched PEI on the market.
TDA‘s Polyethylenimine Linear (PEI) has more amine groups than competitors (+98%)
70% activity retention
Available to purchase as LPEI Sulfate and Ultra-pure Sorbent
Chemical Structure
The repeating unit is - CH2-CH2-NH-.
This linear arrangement results in a polymer backbone with secondary amine groups along the chain and a primary amine at one terminus.
The general formula can be represented as H-(NHCH2CH2)n - NH2.
Molecular structure of LPEI vs branched PEI.
Cationic Polymer: The presence of amine groups makes L-PEI a cationic polymer, especially at acidic to neutral pH where the amines are protonated, giving the polymer a positive charge. The degree of protonation depends on the pH of the solution.
High Charge Density: Due to the repeating amine units, L-PEI possesses a high positive charge density, which is crucial for many of its applications.
Solubility: L-PEI is generally soluble in polar solvents such as hot water, methanol, ethanol, and aqueous solutions with low pH. It is typically insoluble in nonpolar solvents like benzene, ethyl ether, and acetone, as well as cold water.
Melting Point: L-PEI has a higher melting point than branched PEI, typically in the range of 48-75 C, depending on the molecular weight. It exists as a semi-crystalline solid at room temperature.
Molecular Weight: L-PEI is available in a range of molecular weights, which significantly influences its properties and applications.
Hygroscopic: It can absorb moisture from the air.
Properties
Linear PEI can be synthesized through the ring-opening polymerization of 2-ethyl-2-oxazoline followed by hydrolysis. This method allows for better control over the polymer’s linear structure and molecular weight compared to the synthesis of branched PEI.
Synthesis
Gene Delivery: L-PEI is a widely used non-viral vector for gene transfection both in vitro and in vivo. Its positive charge allows it to condense negatively charged nucleic acids into polyplexes, which can then be taken up by cells. The protonation of amines inside endosomes leads to an influx of chloride ions and water, causing osmotic swelling and rupture of the endosome, releasing the nucleic acid into cytoplasm.
Cell Culture: It can be used to coat cell culture surfaces to enhance the attachment of weakly adhering cells due to electrostatic interactions between the positively charged polymer and the negatively charged cell surfaces.
Adhesion Promoter: L-PEI can be used to improve the adhesion of negatively charged dyes and other substances to various surfaces.
Other Applications: Other uses include areas like drug delivery (other than nucleic acids), CO2 capture, and as component in various materials.
Applications