FAQs
Frequently Asked Questions
Categories
General Information
Does Quick-Tissue™ technology leave a genetic footprint?
Sendai virus (SeV) is an RNA virus, so it does not integrate into the genomic DNA. In principle, a foreign gene introduced intracellularly in the form of RNA is quickly translated and expressed because, unlike DNA, RNA does not need to enter the nucleus for forced expression, thereby providing no chance of mutagenesis. This is discussed in the following review paper: Yamamoto, et al., (2009) "Current prospects for mRNA gene delivery." Eur. J. Pharm Biopharm 71, 484-489.
Will SeV remain active after differentiation?
No. The SeV used in our kits is a temperature-sensitive mutant that is active at 33℃ but becomes inactive at 37℃, which is the temperature instructed in the user guides post-differentiation.
Is Sendai virus (SeV) dangerous?
SeV is not pathogenic to humans (i.e., humans are not the natural host of the virus) and the infection does not persist in immunocompetent animals. Furthermore, SeV used in our kits does not produce infectious viral particles upon transduction to host hPSCs and is a temperature-sensitive mutant, such that it is active at 33℃ but becomes inactive at 37℃. However, because SeV can be transmitted by aerosol and contact with respiratory secretions and is highly contagious, appropriate care must be taken to prevent potential mucosal exposure to the virus. Our SeV-based kits must be used under Biosafety Level 2 (BL-2) containment with a biological safety cabinet or a laminar flow hood and with appropriate personal protective equipment. In the event that the virus comes into contact with skin or eyes, decontaminate the affected area by flushing with plenty of water and follow the safety manual prepared by your laboratory and approved by your Institutional Biosafety Committee.
Do I need a license agreement for any of Elixirgen Scientific’s products?
No. You don't need any licence or material transfer agreement (MTA) to use our differentiation kits or iPSC-derived cells. However, please be advised that these products are for research use only.
User Guide Information/Troubleshooting
Why do I see many floating cells and/or cellular debris on day 1?
hPSCs were likely damaged while they were harvested. hPSCs may have been mechanically harvested by scraping or were pipetted too much or too vigorously. Lift Solution D1-treated hPSCs only by pipetting them up and down up to 15 times.
I plated cells as instructed, so why does my culture look less confluent than the one shown in the user guide on day 1?
hPSCs were likely damaged while they were harvested. Ideally, hPSCs should be lifted only by pipetting several times using Solution D1 as instructed in the user guide. Even if pipetting 15 times does not lift all of the cells in the culture, do not attempt to do more pipetting but collect only cells that come off. Instead rinse the culture with PBS and start Solution D1 treatment again but with longer incubation (up to 20 minutes). Next time please reduce the concentration of the substrate used to coat the dish/well for the maintenance of the source hPSCs to 50-70%.
What should I do if I find on day 1 that my culture was seeded only in the center but not in the periphery of the well?
Unless cells are accumulated in the center of the well, the instructions can be followed since this is an issue of coating. We have observed that 4-well plates available from Nunc sometimes do not allow cells to settle down in the periphery of the well when our coating conditions are applied. Next time, please use a 24-well plate and try the following: 1) incubate the plate with Coating Material A at 4°C overnight instead of 37°C for 2 hours, 2) do not aspirate the supernatant completely or leave the supernatant just enough to cover the well bottom surface after coating with Coating Material A is completed and 3) do not touch the bottom of wells with fingers when handling the plate.
What should I do if I find on day 1 that cells were accumulated in the center of the well?
It is not recommended to start mRNA-based differentiation induction because the differentiation efficiency is expected to be quite low. For successful differentiation using our mRNA-based methods including Mesendoderm Booster, hPSCs should be evenly distributed in the well. It is likely that the plate was shaken too much, and cells were accumulated in the center of the well while they were floating. Next time, please handle the plate more gently or it can be left on a flat bench top without vibration for 15 min before it is put inside a CO₂ incubator.
