Keeping edited cells healthy
Yuhong Cao with a tiny nanoEP filter. (Photo by Adam Lau)
Editing T-cells with CRISPR-Cas9 can improve immunotherapy outcomes and shows promise for treating diseases such as cancer. To avoid the numerous problems with virus-based delivery systems, researchers often use an electric charge to open holes in cells to deliver the Cas9 molecule. But T-cells are sensitive, and about half break apart from the procedure. Now, postdoctoral fellow Yuhong Cao has developed a new technique that doubles the effectiveness of the process. In a recent study co-authored by chemistry and materials science and engineering professor Peidong Yang, Doudna and others, Cao demonstrated the effectiveness of using inexpensive lab equipment to deliver macromolecules into cells.
“Cells are precious — if you kill too many, you won’t have enough cells for therapy,” Cao says. So, using a common laboratory filter, she created a gentler method to open holes, with a nearly 100% cell survival rate. When cells are loaded onto the filter, its pores serve as a physical template, effectively stenciling tiny, controlled openings into the cell membrane when an electric field is turned on. The voltage also pulls macromolecules placed on the filter through the pores and into the cell. Turn off the electricity and the pores close up. “That’s how we keep the cell heathy,” she says.
The technique, called nanopore-electroporation, or nanoEP, is already being adopted in other labs. Medical applications will require scaling up from about 10,000 cells to millions. Sizing up by that magnitude creates challenges like keeping the electric field uniform across a much larger membrane. “This is an engineering problem,” Cao says.