For most infectious diseases, diagnosis requires specialized expertise, sophisticated equipment and ample electricity ― all of which are in short supply in many places where illnesses such as Lassa fever occur. The CRISPR tests offer the tantalizing possibility of diagnosing infections as accurately as conventional methods, and almost as simply as an at-home pregnancy test. And because CRISPR is engineered to target specific genetic sequences, researchers hope to develop a tool based on the technology that can be fine-tuned to identify, within a week, whatever viral strain is circulating.
“This is a very exciting direction for the CRISPR field to go in,” says Jennifer Doudna, a biochemist at the University of California, Berkeley, who is developing some of these tools.
Uwanibe and her team are running trials of a CRISPR diagnostic developed by researchers at the Broad Institute of MIT and Harvard in Cambridge, who had paired CRISPR with the Cas13 protein1. Unlike Cas9 — the enzyme originally used in CRISPR gene editing — Cas13 cuts the genetic sequence that it’s been told to target, and then starts slicing up RNA indiscriminately. This behaviour presents a problem when trying to edit genes, but it’s a boon for diagnostics because all that cutting can serve as a signal.