EXTRACTION WITHOUT KILLING: Cells are cultured atop a polycarbonate membrane perforated in spots by vertical aluminum oxide nanostraws. At defined locations, where the membrane has been etched away lithographically, the nanostraws protrude from the membrane and contact the cells. A brief electric voltage is passed across the nanostraws, causing temporary perforations in the cell membrane. This allows small volumes of cytoplasm to diffuse into the nanostraws for collection in the reservoir of extraction buffer below the polycarbonate membrane.
See the full infographic: WEB © GEORGE RETSECK
Analyzing cells en masse provides a general idea of the happenings within a given cell type, but misses the subtle yet significant variations between individual cells—variations that may result in different responses to developmental signals, drugs, and other factors.
To better explore the inherent heterogeneity of cell populations, “many people are trying to do single-cell analyses,” says Orane Guillaume-Gentil of the Swiss Federal Institute of Technology (ETH). But, she adds, the approaches are limited. “You have to kill the cells, so you cannot see anything dynamic, and you also lose the [spatial] context of the cells.”
The problem, agrees Nicholas Melosh of Stanford University, is that “you want to know what a cell is, but [current single-cell approaches] tell you what it was.”
Researchers are ...
