Making light work of cell sorting

Researchers at MIT have developed a new method for cell sorting that they say will make the process faster and cheaper and allow for new types of experiments.

MIT has developed a system for sorting cells that involves special "traps" in a silicone layer bonded to a microscope slide. Cells with specific properties are then levitated out of their traps using the pressure of a beam of targeted light from a low-cost laser. A flowing fluid then sweeps the selected cells off to a reservoir. courtesy / Joseph Kovac, MIT

Current sorting methods rely on labelling cells with fluorescent markers, which respond to particular proteins or compounds by emitting light. The group at MIT have improved the precision of this technique by separating the cells based on the response of particular components, like the nucleus, rather than the cell as a whole.

This new method opens up the possibility of looking at how elements of a cell change over time. Unlike expensive separation techniques, such as optical tweezers, the group at MIT expect that once their system is refined, it will only cost a few thousand dollars.

Their system can sort up to 10,000 cells on a single conventional glass microscope slide which is bonded to a silicone layer. The silicone layer is made with thousands of tiny cavities, which act like traps for the cells. Each cell’s fluorescence can be either manually or computationally checked against specific criteria. At the end of the selection process, groups of cells can be levitated out of their traps to a separate reservoir using the light pressure from a low cost laser, which is gentle enough not to disturb the cells. Joel Voldman, an associate professor in MIT’s Department of Electrical Engineering and Computer Science described this process like “a fire hose pushing up a beach ball.”

He also noted that their new system would make it possible to research why some cells respond to the labelling process faster than others. Their methodologies could also be applied to fields which require the selection of cells with particular characteristics, such as clinical testing, genetic screening and cloning research.

Leila Sattary