Hello,

I'm working on drug delivery in cancer cells. For that, I prepared slides of adherent cancer cells for confocal microscopy. I fixed the cells with 150 ul of 4% paraformaldehyde for 10 min and mounted the cover slip on a glass slide. Then I stored the slides at -20 degC. After one day I did imaging, I found that cells got flattened morphology and some granular structures were seen inside the cells that were totally different from their morphology. Imaging was also not good. I've some doubts regarding this:

1. Whether the incubation time with paraformaldehyde (10 min) was more than required or storage at -20 degC damaged the cells?

2. What should be the optimum time and volume of paraformaldehyde incubation?

3. At what temperature we can store the mounted slides and for how long?

Please guide me regarding this.

Thank you