Gotcha! These little pyramids are actually microscopic traps designed to gently enclose single cells without killing them. The idea is that in the future, such traps could be a part of a system for capturing and analyzing individual cells, perhaps as a part of cancer monitoring.
The traps, which are made out of silicon oxides, start out as flat, star-like shapes. When they're dipped into a saline solution, the arms automatically begin to fold inward along their hinges, capturing any cells that might be nearby at the time. In a new study, the traps' creators have shown the little nano-stars are able to grip two different kinds of mouse cells without killing them: red blood cells and fibroblasts, which are a type of connective tissue cell.
