I'm using nigericin to stimulate NLRP3 inflammasome in THP1 cell recently. The nigericin is diluted to 100mM with ethonal and preserved in -20 degree. 

The experiment protocol is:

1. Treated THP-1 cell with LPS for 1h, 8h, 17h and 24h respectively in 12-well plate

2. Add 10 micromole nigericin to each well to activate NLRP3 inflammasome for 30 min, and then collect the supernatant to test IL-1beta.

Before adding nigericin to cell medium, I used opti-MEM to pre-dilute it. Only 1 microlitre of nigericin could cause obvious precipitation in opti-MEM. Will it affect the experiment result? Which kind of solution is normally used to dilute nigericin when you use it?

Thank you for the answer!