Figure 1.

Preparation of CriPs. Purified bacterial Cas9 protein that is carefully processed to remove endotoxin and other contaminants is used for loading of sgRNA. The sgRNA sequence is designed to target a selected gene at a site adjacent to a PAM sequence in the DNA of that target gene. The loaded Cas9–sgRNA nanocomplexes are then coated with an amphipathic peptide, denoted as EP, which is required to mediate uptake of the Cas9–sgRNA complexes into live cells without toxicity or detectable damage.