SAINT-MIX is a transfection kit based on a synthetic amphiphilic (non-liposomal) delivery system manufactured by Synvolux. SAINT-MIX is composed of 2 chemicals, SAINT-18 (1-methyl-4-(cis-9-dioleyl)methylpyridinium-chloride) and DOPE (Dioleoyl-phosphatidylethanolamine) dissolved in H
2O to form a cationic pyridinium head group enabling DNA delivery. The standard conditions recommended for use are 1µg DNA complexed with 15 nmol of SAINT-MIX.The 4 mL package includes 2 glass vials with 2 mL SAINT-MIX each (0.75 mM concentration) and 3 glass vials with 15 mL Hepes Buffer. This 4 mL package is sufficient to perform transfection experiments with 200 µg DNA, using standards conditions. SAINT-MIX can be stored at 4-7ºC for at least 1 year without detectable loss of transfection efficiency.
I regularly use SAINT-MIX to perform stable DNA transfections, as well as transient DNA transfections on human mammary carcinoma cells (MCF-7, MDA-MB-231) and human prostate cancer cells (DU-145, LnCAP). In terms of efficiency, this product always gave me great satisfaction. The diverse steps to perform a transfection using SAINT-MIX are easy to carry out and the first part of the transfection doesn’t require longer than 30 minutes. However, the protocol suggests that another volume of media is added 2 or 3 hours after the cells have been incubated with the SAINT-MIX/DNA complex. This last step extends the overall transfection process time to approximately 3 hours. Thus, a transfection experiment using SAINT-MIX is not so convenient to perform since it requires quite a long period, while transfection with some other systems can be performed within 20 minutes in total.
The package includes enough sterile hepes buffer to mix with SAINT-MIX reagents and DNA following the protocol requirements. Nevertheless, depending on the cell-line used, the transfection efficiency depends on whether the cells are washed with hepes buffer prior to the transfection. Thus, if the cells need to be washed before the transfection, the provided volume of hepes buffer included in the package will not be enough, so that you will need to purchase or make additional sterile hepes buffer.
I have also noticed that with SAINT-MIX the transfection efficiency depends on several points such as the cell-lines used, the transfected DNA length, SAINT-MIX concentrations, the incubation time between the transfection steps and the final addition of media, the wash with buffer prior to the transfection or not, using serum supplemented media or serum free media, etc. A standard protocol is then hard to establish within a team and the best transfection method for using SAINT-MIX can take a while to be determined.
Finally, although the protocol indicates that SAINT-MIX reagents are not toxic, I have noticed that, depending on cell-lines used, performing transfection using SAINT-MIX can alter cell homeostasis. Thus, the level of cell recovery can also depend on the various points stated above, such as using serum supplemented media or serum free media, the incubation times between the transfection steps and the final addition of media and the relative volumes of media finally added.