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DESCRIPTION:
Polyethylenimine (PEI) or polyaziridine is a polymer with repeating units composed of the amine group and two carbon aliphatic CH2CH2 spacers.
Linear polyethyleneimines contain all secondary amines, in contrast to branched PEIs which contain primary, secondary and tertiary amino groups.
Totally branched, dendrimeric forms were also reported.
CAS Number: 9002-98-6
SYNONYMS OF POLYETHYLENEIMINE (PEI):
PEI-10,polyethyleneimine, branched, m.w. 1800,Aziridine,homopolymer,polyethylenimine(10,000),POLYETHYLENEIMINE, BRANCHED,PEI-35,PEI-2500,PEI-1500,polyethylenimine(20,000);,Ethyleneimine,homopolymer
PEI is produced on an industrial scale and finds many applications usually derived from its polycationic character.
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
PROPERTIES OF POLYETHYLENIMINE (PEI):
The linear PEI is a semi-crystalline solid at room temperature while branched PEI is a fully amorphous polymer existing as a liquid at all molecular weights.
Linear polyethyleneimine is soluble in hot water, at low pH, in methanol, ethanol, or chloroform.
Polyethylenimine is insoluble in cold water, benzene, ethyl ether, and acetone.
Linear polyethyleneimine has a melting point of around 67 °C.
Both linear and branched polyethyleneimine can be stored at room temperature.
Linear polyethyleneimine is able to form cryogels upon freezing and subsequent thawing of its aqueous solutions.
SYNTHESIS OF POLYETHYLENIMINE (PEI):
Branched PEI can be synthesized by the ring opening polymerization of aziridine.
Depending on the reaction conditions different degree of branching can be achieved.
Linear PEI is available by post-modification of other polymers like poly(2-oxazolines) or N-substituted polyaziridines.
Linear PEI was synthesised by the hydrolysis of poly(2-ethyl-2-oxazoline) and sold as jetPEI.
The current generation in-vivo-jetPEI uses bespoke poly(2-ethyl-2-oxazoline) polymers as precursors.
APPLICATIONS OF POLYETHYLENIMINE (PEI):
Polyethyleneimine finds many applications in products like: detergents, adhesives, water treatment agents and cosmetics.
Owing to its ability to modify the surface of cellulose fibres, PEI is employed as a wet-strength agent in the paper-making process.
Polyethylenimine (PEI) is also used as flocculating agent with silica sols and as a chelating agent with the ability to complex metal ions such as zinc and zirconium.
There are also other highly specialized PEI applications:
Biology:
PEI has a number of uses in laboratory biology, especially tissue culture, but is also toxic to cells if used in excess.
Toxicity is by two different mechanisms, the disruption of the cell membrane leading to necrotic cell death (immediate) and disruption of the mitochondrial membrane after internalisation leading to apoptosis (delayed).
Attachment promoter:
Polyethyleneimines are used in the cell culture of weakly anchoring cells to increase attachment.
PEI is a cationic polymer; the negatively charged outer surfaces of cells are attracted to dishes coated in PEI, facilitating stronger attachments between the cells and the plate.
Transfection reagent:
Poly(ethylenimine) was the second polymeric transfection agent discovered,after poly-L-lysine.
PEI condenses DNA into positively charged particles, which bind to anionic cell surface residues and are brought into the cell via endocytosis.
Once inside the cell, protonation of the amines results in an influx of counter-ions and a lowering of the osmotic potential.
Osmotic swelling results and bursts the vesicle releasing the polymer-DNA complex (polyplex) into the cytoplasm.
If the polyplex unpacks then the DNA is free to diffuse to the nucleus.
Permeabilization of gram negative bacteria:
Poly(ethylenimine) is also an effective permeabilizer of the outer membrane of Gram-negative bacteria.
CO2 CAPTURE:
Both linear and branched polyethylenimine have been used for CO2 capture, frequently impregnated over porous materials.
First use of PEI polymer in CO2 capture was devoted to improve the CO2 removal in space craft applications, impregnated over a polymeric matrix.
After that, the support was changed to MCM-41, an hexagonal mesostructured silica, and large amounts of PEI were retained in the so-called "molecular basket".
MCM-41-PEI adsorbent materials led to higher CO2 adsorption capacities than bulk PEI or MCM-41 material individually considered.
The authors claim that, in this case, a synergic effect takes place due to the high PEI dispersion inside the pore structure of the material.
As a result of this improvement, further works were developed to study more in depth the behaviour of these materials.
Exhaustive works have been focused on the CO2 adsorption capacity as well as the CO2/O2 and CO2/N2 adsorption selectivity of several MCM-41-PEI materials with PEI polymers.
Also, PEI impregnation has been tested over different supports such as a glass fiber matrix and monoliths.
However, for an appropriate performance under real conditions in post-combustion capture (mild temperatures between 45-75 °C and the presence of moisture) it is necessary to use thermally and hydrothermally stable silica materials, such as SBA-15, which also presents an hexagonal mesostructure.
Moisture and real world conditions have also been tested when using PEI-impregnated materials to adsorb CO2 from the air.
A detailed comparison among PEI and other amino-containing molecules showed an excellent performance of PEI-containing samples with cycles.
Also, only a slight decrease was registered in their CO2 uptake when increasing the temperature from 25 to 100 °C, demonstrating a high contribution of chemisorption to the adsorption capacity of these solids.
For the same reason, the adsorption capacity under diluted CO2 was up to 90% of the value under pure CO2 and also, a high unwanted selectivity towards SO2 was observed.
Lately, many efforts have been made in order to improve PEI diffusion within the porous structure of the support used.
A better dispersion of PEI and a higher CO2 efficiency (CO2/NH molar ratio) were achieved by impregnating a template-occluded PE-MCM-41 material rather than perfect cylindrical pores of a calcined material, following a previously described route.
The combined use of organosilanes such as aminopropyl-trimethoxysilane, AP, and PEI has also been studied.
The first approach used a combination of them to impregnate porous supports, achieving faster CO2-adsorption kinetics and higher stability during reutilization cycles, but no higher efficiencies.
A novel method is the so-called "double-functionalization".
It is based on the impregnation of materials previously functionalized by grafting (covalent bonding of organosilanes).
Amino groups incorporated by both paths have shown synergic effects, achieving high CO2 uptakes up to 235 mg CO2/g (5.34 mmol CO2/g).
CO2 adsorption kinetics were also studied for these materials, showing similar adsorption rates as impregnated solids.
This is an interesting finding, taking into account the smaller pore volume available in double-functionalized materials.
Thus, it can be also concluded that their higher CO2 uptake and efficiency compared to impregnated solids can be ascribed to a synergic effect of the amino groups incorporated by two methods (grafting and impregnation) rather than to a faster adsorption kinetics.
Low work function modifier for electronics :
Poly(ethylenimine) and poly(ethylenimine) ethoxylated (PEIE) have been shown as effective low-work function modifiers for organic electronics by Zhou and Kippelen et al.
It could universally reduce the work function of metals, metal oxides, conducting polymers and graphene, and so on.
It is very important that low-work function solution-processed conducting polymer could be produced by the PEI or PEIE modification.
Based on this discovery, the polymers have been widely used for organic solar cells, organic light-emitting diodes, organic field-effect transistors, perovskite solar cells, perovskite light-emitting diodes, quantum-dot solar cells and light-emitting diodes etc.
USE IN DELIVERY OF HIV-GENE THERAPIES:
Polyethylenimine (PEI), a cationic polymer, has been widely studied and shown great promise as an efficient gene delivery vehicle.
Likewise, the HIV-1 Tat peptide, a cell-permeable peptide, has been successfully used for intracellular gene delivery
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.
FEATURES AND BENEFITS OF POLYETHYLENEIMINE:
Primary and secondary amine groups of PEI can efficiently bind to drugs, nucleic acids, and other functional moieties.
Branched PEI has better complexation and buffering capacity.
CHEMICAL AND PHYSICAL PROPERTIES OF POLYETHYLENEIMINE (PEI):
Chemical formula, (C2H5N)n, linear form
Molar mass, 43.04 (repeat unit), mass of polymer variable
form
viscous liquid
mol wt
average Mn ~10,000 by GPC
average Mw ~25,000 by LS
impurities
≤1% water
refractive index
n20/D 1.5290
viscosity
13,000-18,000(50 °C)
bp
250 °C (lit.)
density
1.030 g/mL at 25 °C
Melting point, 59-60°C
Boiling point, 250 °C(lit.)
Density, 1.030 g/mL at 25 °C
vapor pressure, 9 mmHg ( 20 °C)
refractive index, n20/D 1.5290
Flash point, >230 °F
storage temp., 2-8°C
solubility, DMSO (Sparingly)
form, Liquid
color, Pale yellow
Specific Gravity, 1.045 (20/4℃)
PH, pH(50g/l, 25℃) : 10～12
Water Solubility, Soluble in water.
Sensitive, Hygroscopic
InChI, InChI=1S/C2H5N/c1-2-3-1/h3H,1-2H2
InChIKey, NOWKCMXCCJGMRR-UHFFFAOYSA-N
SMILES, C1NC1
LogP, -0.969 (est)
SAFETY INFORMATION ABOUT POLYETHYLENEIMINE (PEI):
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
