This question is part of the following Ask The Expert session:
The best reagent to transfect mRNA to cells is Lipofectamine® MessengerMAX™ because it has shown to further protect the mRNA molecules from degradation and has been shown to deliver the highest amount of mRNA into a wide variety of cell types. For tissues or small animal models it would be Invivofectamine® 2.0, which is a nanoparticle technology that can encapsulate and protect the payload for delivery. It can be used on cells in vitro as well as injected systemically via intravenous route or via direct injection (i.e. muscle, tumors, heart, brain). More information can be found at www.lifetechnologies.com/messengermax and www.lifetechnologies.com/invivofectamine
In addition, mRNA can also be synthesized with chemically modified nucleotides to improve stability and further minimize degradation. A positive control mRNA (e.g. GFP mRNA) is also a very helpful method to optimize transfection techniques.