ACS Nano doi:10.1021/nn2012767 (2011)

Selective separation of cells in culture is useful for single-cell studies in stem-cell research, organ culturing and tissue engineering. Current methods such as aspirating cells with capillaries are tedious and are at risk of contamination. Now, Tsuyohiko Fujigaya, Naotoshi Nakashima and colleagues of Kyushu University and the Japan Science and Technology Agency have shown that cultured cells can be selectively removed and collected using near infrared laser.

The Japanese team coated a conventional cell culture dish with single-walled carbon nanotubes and allowed cells to grow as they would on a control glass substrate. Because carbon nanotubes are responsive towards a near infrared laser and biological tissues are transparent in this region, cells that were irradiated with short pulses of the laser detached from the culture dish immediately. By focusing the laser using different objective lenses, it is possible to detach either large numbers of cells or single cells, suggesting that this method can be used to 'catapult' and pattern cells on substrates. Cells that were detached in this way retained their morphology and genetic information. However, Raman mapping of the irradiated area revealed that carbon nanotubes were detached along with the cells.

Although it is thought that the irradiation induced a photoacoustic effect that detached the cells, the exact mechanism of cell removal and the implication of the detached nanotubes on subsequent studies need to be explored further.