On several occasions, I have gone to split cells and realized that there was a small glacier floating in my trypsin. Repeatedly freezing and thawing trypsin also lowers its effectiveness. Now there is a solution to these problems that is more innovative than simply making aliquots of trypsin. TrypLE Express is a new, stable, trypsin-like enzyme from Invitrogen that can be stored either at room temperature (for several months) or refrigerated (for longer storage). When I received a free sample, I found that the convenience was unbeatable.
I have been using TrypLE Express for 293T cells (very weakly adherent) and MDCK cells (almost impossible to dissociate) and it works well for both. I did not have to modify the procedure for splitting cells in any way when I switched to this product. The MCDK cells don’t lift up immediately but do dissociate within a reasonable amount of time. You can’t buy a stronger version (as you can with trypsin-EDTA) so it may not be suitable for certain applications with strongly adherent cell lines. On the other hand, TrypLE Express is gentler on cells than a strong protease, which may improve the protocol for certain applications. The consistency seems slightly different than trypsin, but it does not appear to affect the cells. Unlike other innovative cell culture products that I have tried, I did not notice a phenotypic change in either cell line.
For researchers who feel uncomfortable using animal-based products for either scientific or ethical reasons, this enzyme is a recombinant alternative to traditional trypsin. The microbial fermentation process used to produce the enzyme ensures that it is very pure, which is not always the case for animal-derived products. TrypLE Express can be used with or without serum, although I have not tried it without serum. It is available with or without phenol red to accommodate different cell lines and uses. Unlike regular trypsin, there is no need to inhibit TrypLE Express. Testing conducted by Invitrogen suggests that there are no obvious disadvantages to TrypLE Express in terms of cell growth, morphology, or other features. Although I have not done controlled comparisons, my subjective experience corroborates their findings.
In most cases, products that make an experiment more convenient cost a lot more than the traditional product. TrypLE Express is only pennies more than the standard trypsin-EDTA, so you don’t have to convince your boss why you need it. The only disadvantage I can think of is that our on-site cell culture store does not have it in stock – but that may change too. I would expect that as more people are aware that this product is available, a certain percentage will become loyal users.
Tara Lauriat
Graduate Student
Mount Sinai School of Medicine
New York, NY