I just purified some recombinant Cas9 protein and want to know if it has activity or not in cells. Do you have a reference paper or protocol I can follow?
I would recommend using Lipofectamine CRISPRMax with a known high activity gRNA; this is what our lab does for routine gRNA testing. The protocol is relatively quick and easy and is highly effective on most common cells lines. There are several well validated Rosa26 (for mouse) or AAVS gRNAs (for human) that should work well. Here's a link to one of the common Rosa26 ones: