So far, several anti-CRISPR proteins have been identified, but they are not without significant limitations. These proteins are large molecules, often too big to enter cells. They also are not easily reversible, and can be flagged and attacked by the immune system.
The new research set out to find synthetic small-molecule CRISPR inhibitors that are safe, reversible and effectively disrupt the interaction between CRISPR-Cas9 and DNA. After developing a novel screening platform that can closely measure the activity of the CRISPR enzyme within a cell, the researchers screened around 15,000 different potential compounds to find the ones most effective at inhibiting that CRISPR activity.
Read more at New Atlas