DNA ‘Yarn Balls’ Deliver Biomolecules

Biotechnology companies are becoming increasingly fixated with the genome-editing technique known as CRISPR/Cas9 (see page 14). For this potentially therapeutic technology to safely and selectively alter genes of living cells, scientists need to develop reliable methods to shuttle biomolecules into cell nuclei to edit genetic material. Researchers from the University of North Carolina, Chapel Hill, and North Carolina State University have now developed DNA nanoparticles that effectively deliver DNA-cleaving Cas9 proteins to their target (Angew. Chem. Int. Ed. 2015, DOI: 10.1002/anie.201506030). Led by Zhen Gu and Chase L. Beisel, the team synthesized DNA strands that self-assemble into particles resembling nanoscopic balls of yarn, or clews. Then they loaded the particles with Cas9 and guide RNA molecules that tell the protein where to snip genomic DNA. An outer coating of polyethylenimine helps the particles release their gene-editing biomolecules after they are engulfed by cells. The team now aims to establish that their nanoparticles remain stable in the body’s extracellular environment and can be adorned with a variety of attachments other than Cas9.