I have bought 1 gram powder 40 kDa (22 kDa free base) PEI from Polysciences and I´m planning to use it for in vivo DNA transfection in a veterinary clinical trial. How is PEI mM calculated in solution? I need to transfect approximately 4 mg of DNA in 1 mL final solution volume and I do not know which volume I have to dilute the PEI.
Many thanks!
Dear Martin!
Please You look at this protocol:
Article Transient Mammalian Cell Transfection with Polyethylenimine (PEI)
Polyethylenimine ‘Max’ (linear, MW 25 000) (Polysciences, Inc.)
3.1. Solutions & buffers
PEI ‘Max’Dissolve 1 g PEI ‘Max’ in 900 ml distilled water. Adjust the pH to 7.0 with 1 N NaOH. Add distilled water to 1 l
@Martin Williams
Am not sure whether you are asking about preparing the solution or how to calculate molarity! if it is preparation then product insert should help you (https://www.polysciences.com/media/amasty/amfile/attach/eTdgDn0WkXlffW2Vy5rtnkXX0odfR8G6.pdf). If it is molarity, then M = 1g x (1L/25,000) = 0.00004M = 0.04mM in 1L solution. hope this helps.
Many thanks Alexandr Chernov and Rabeah Al-Temaimi for your replies.
I have 1 gram of PEI powder and I need to dilute it with water.
I have to do a clinical trial in canine, and I need to transfect up to 2 mg of DNA, but everywhere I search it says that PEI has to be diluted 1 g/L (1 mg/mL) but with that concentration, the a max 0.5 mg/mL of DNA concentration can be transfected, and I need to transfect 2 mg of DNA in 1mL or 2mL (max)
What happens if I dilute PEI 1g/500mL (2 mg/mL) ? Does it precipitate?
Many thanks
You are welcome Martin Williams , yes you can make a different concentration in accordance with your requirement. For example, for HEK cells 1µl of 2mg/ml PEI for each µg of DNA may be used. Add the PEI into the DNA mix, incubate for 5 minutes and add to the cells in full growth medium. Transfection efficiency is consistently almost 100%. Alternatively check this protocol (http://wolfson.huji.ac.il/expression/mammalian/PEI%20transfection%20of%20HEK29.doc)
Dear Rabeah Al-Temaimi thanks for your reply, but I think you did not understand me. I have to do a clinical trial, meaning that I will inject PEI/DNA into a living organism (in this case, dog) not transfect into a cell culture, so my question is about the concentration of PEI when I need to inject 2 mg of DNA in 1 mL of final formulation.
Thanks
Martin Williams regular PEI for in vivo experiments is not recommended due to its inhibition by serum proteins (PMID: 18597881) modified PEI reagents like invivoJet-PEI (https://www.polyplus-transfection.com/products/in-vivo-jetpei/) have better transfection in vivo, in fact most studies use JetPEI for animal delivery. You can certainly try using regular PEI at your required conc of 2mg/ml with 2mcg DNA but having worked on dogs myself I would hate to put them through it when i know its efficiency is reduced. Hope this helps.
Many thanks Rabeah Al-Temaimi !
What kind of transfection reagent will you advice me to use instead of PEI? I know jetPEI is for in-vivo transfection but is extremely expensive for industrial application.
Many thanks and kind regards!
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