Researchers at the Fred Hutchinson Cancer Research Center have proposed gold nanoparticles as a new way to deliver CRISPR Cas-12a to cells. These nanoparticles can be filled with the necessary CRISPR components to edit genes cleanly, with between 10% and 20% of targeted cells successfully edited during lab studies. No toxic side effects were found from the process.

Historically, scientists have found it difficult to deliver CRISPR into cells. Attempts using electric shocks to open cell membranes can lead to cell death, while using viruses as couriers may have unintentional side effects.

The scientists found cells swallow the new carrier in under six hours, with gene editing taking place within 48. Gene editing in mice peaked eight weeks after the injection, with edited cells still in circulation 22 weeks later.

The study, published in Nature Materials, engineered the gold nanoparticles to avoid cell organelles looking to destroy them and enter the cell nucleus.

Gold was chosen due to attributes including microscopic spheres on the surface which easily attaches to different types of molecule. A laboratory-grade liquid gold was mixed into a substance that prompts gold ions to form particles. Those that were 19 nanometres wide were selected – the width is enough to hold the CRISPR components but small enough to still pass through cell walls.

While other groups are also using gold to deliver CRISPR, including scientists at GenEdit using it to treat Duchenne muscular dystrophy, the Fred Hutchinson team said they could be the first to target blood stem cells with gold nanoparticles carrying CRISPR components.

From here, the team said they are looking to boost the effectiveness of the delivery system so 50% or more targeted cells are edited. They are also looking for a commercial partner to hopefully start clinical trials in the next few years.