Polyethylenimine Linear(PEI) MW40000(rapid lysis)

Polyethylenimine Linear MW40000, also abbreviated as PEI 40000, is a highly charged cationic polymer with a molecular weight of 40,000 that binds negatively charged nucleic acid molecules very easily, forming a complex and allowing the complex to enter cells. PEI 40000 is a transient transfection reagent with low cytotoxicity, high transfection efficiency, and high gene expression efficiency in cells such as HEK293 and CHO.

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Product Description

Compared with PEI 25000 transfection reagent, PEI 40000 has many advantages as follows:

1. PEI 40000 is easy to dissolve and can be directly dissolved in water. PEI 25000 needs to first adjust the water to weak acid to help it dissolve, and then use NaOH to adjust the pH to neutral;

2. PEI 40000 is easy to operate, easier to use, and has a better transfection effect than PEI 25000; 3. PEI 25000 contains 4-11% propionyl residues, which can prevent the polymer backbone from binding to DNA. Compared to PEI 25000, PEI 40000 is a complete shed construction, so its performance is consistently efficient.

This product is an instant type, which dissolves quickly and is easy to prepare.

Product Properties

Performance Details

English Name

Polyethylenimine Linear (PEI) MW40000 



Molecular formula


Molecular weight



White or off-white solid


Soluble in water, insoluble in organic solvents: benzene, ether, and acetone


Shipping and Storage

The product is shipped at room temperature and the powder can be stored at 2-8ºC for two years. The stock solution is stored at 2-8 ºC for 3 months.


1) For most cells, 3.0 μL of PEI 40000 Transfection Reagent per 1 μg of DNA yields high transfection efficiencies. Also, try to optimize using linear PEI 40000 transfection reagent in volumes of 1.5~4 μL per 1 μg of DNA.

2) For your safety and health, please wear lab coats and disposable gloves for operation.

3) For research use only!

Storage liquid configuration(1 mg/mL)

1. Material

PEI 40000, Milli-Q® water/water for injection (WFI) or similar bio-grade water, 12 mol/L hydrochloric acids,1 mol/L sodium hydroxide (NaOH), disposable 0.1~0.2 μm PES vacuum sterile filter, sterile HDPE or poly Acrylic storage bottle.

2. Configure the storage solution(1 mg/mL)

1) In a 1 L glass beaker, add 1 g of PEI 40000 powder to 900 mL of Milli-Q® ultrapure water or other equivalent biological water, stir evenly on a magnetic stirrer, and generate small vortices.

2) Wait until PEI 40000 is completely dissolved (usually less than 5 mins);

3) Use 12 mol/L hydrochloric acid and1 mol/L sodium hydroxide solution dropwise while stirring to adjust the pH to 6.80~6.90;

【Note】 please use hydrochloric acid to adjust the pH value to 6.80~6.90;

4) Transfer the solution to a graduated cylinder, and add water to make up to 1 L.

5) Filter and sterilize with a disposable 0.1~0.2 µm PES vacuum filter to obtain a stock solution of 1 mg/mL.

6) Aliquot as needed and store at 2-8 °C, stable for 3 months.

Instructions (Take the 6-well plate as an example)

1. Inoculate cells: In order to improve the transfection efficiency, it is recommended to inoculate cells one day before transfection, and the cell density should be 70%~80%.

2. Prepare DNA-PEI complexes: Prepare DNA-PEI nucleic acid-transfection reagent complexes according to the following system:

1) For each well of cells, dilute 2 μg of target DNA with 100 μL of serum-free medium, and mix thoroughly to form a DNA dilution solution.

【Note】 Opti-MEM or ddH2O is recommended for serum-free diluents.

2) Immediately add 4 μL of PEI 40000 Transfection Reagent to 100 μL of DNA Diluent,  and mix well gently.

3) Incubate at room temperature for 10-15 mins to form a DNA-PEI cationic nucleic acid transfection reagent complex.

3. Transfect cells

1) During complex formation, remove the cell growth medium and add 2 mL of fresh prewarmed complete medium to each well.

2) Add 100 μL of DNA-PEI nucleic acid-PEI complex directly to the cells, and mix gently.

3) Culture in a 37 ℃, 5% CO2 incubator, and the expression of the transfected gene can be detected as soon as 5 hours after transfection. Please determine the appropriate detection time by yourself.

4. Steady transfer screening (optional)

24 h after transfection, cells were passaged into a fresh growth medium (dilute cells more than 10-fold) and incubated overnight at 37 °C in a 5% CO2 incubator. The screening drug matching the transfection resistance gene was added the next day. Drug-resistant clones can be screened in about 1 to 2 weeks, and the growth medium containing the screened drugs needs to be changed frequently during this period.

The amount of transfection in different cell culture vessels (for reference only):

Culture vessel

Surf. area per well 1 (cm2)


transfection reagent(μL)

Vol. of dilution medium 2(μL)

Vol. of plating medium






100 μL






200 μL






500 μL






1 mL






2 mL

Flask 25cm2





4 mL

Flask 75cm2 





10 mL

1. The surface area of cell culture plates provided by different manufacturers may vary;

2. Volume of the medium used to dilute DNA.


Polyethylenimine Linear(PEI) MW40000rapid lysis FAQ

(1) Q: Can 40816 be made into 10× mother liquor and stored at -20℃?

A: It is recommended to store in accordance with the storage conditions of 2-8 ℃ in the instructions. Do not store at -20°C, use hydrochloric acid to make the pH slightly acidic, pH 6.8, and then store at -20°C,


However, the storage time cannot exceed one year. When using it again, take it out and measure the pH. If the pH is between 6.8 and 6.9, it can be used directly. Otherwise, the pH needs to be adjusted, and it cannot be frozen again to avoid repeated freezing and thawing. It is more troublesome and may affect the transfection efficiency, so it is not recommended.

Citations & References:

[1] Luo J, Yang Q, Zhang X, et al. TFPI is a colonic crypt receptor for TcdB from hypervirulent clade 2 C. difficile. Cell. 2022;185(6):980-994.e15. doi:10.1016/j.cell.2022.02.010(IF:41.584)

[2] Chen Y, Luo R, Li J, et al. Intrinsic Radical Species Scavenging Activities of Tea Polyphenols Nanoparticles Block Pyroptosis in Endotoxin-Induced Sepsis [published correction appears in ACS Nano. 2022 Mar 3;:]. ACS Nano. 2022;16(2):2429-2441. doi:10.1021/acsnano.1c08913(IF:15.881)

[3] Chen ZH, Yan SM, Chen XX, et al. The genomic architecture of EBV and infected gastric tissue from precursor lesions to carcinoma. Genome Med. 2021;13(1):146. Published 2021 Sep 7. doi:10.1186/s13073-021-00963-2(IF:11.117)

[4] Huang G, Liu D, Wang W, et al. High-resolution structures of human Na<sub>v</sub>1.7 reveal gating modulation through α-π helical transition of S6<sub>IV</sub>. Cell Rep. 2022;39(4):110735. doi:10.1016/j.celrep.2022.110735(IF:9.423)

[5] Tian X, Liu L, Jiang W, Zhang H, Liu W, Li J. Potent and Persistent Antibody Response in COVID-19 Recovered Patients. Front Immunol. 2021;12:659041. Published 2021 May 28. doi:10.3389/fimmu.2021.659041(IF:7.561)

[6] Lin J, Chen Z, Yang L, et al. Cas9/AAV9-Mediated Somatic Mutagenesis Uncovered the Cell-Autonomous Role of Sarcoplasmic/Endoplasmic Reticulum Calcium ATPase 2 in Murine Cardiomyocyte Maturation. Front Cell Dev Biol. 2022;10:864516. Published 2022 Apr 1. doi:10.3389/fcell.2022.864516(IF:6.684)

[7] Nian F, Qian Y, Xu F, Yang M, Wang H, Zhang Z. LDHA promotes osteoblast differentiation through histone lactylation. Biochem Biophys Res Commun. 2022;615:31-35. doi:10.1016/j.bbrc.2022.05.028(IF:3.575)