Biomed. Opt. Express 3, 447–454 (2012)

Credit: © 2012 OSA

The ability to switch and control electrical signals in the brain would help researchers tackle many of the outstanding questions in neuroscience. Katherine Lugo and co-workers from the University of Washington in the USA have now demonstrated an optical control scheme that uses quantum dots to control cellular activity and signalling. Optically exciting a quantum dot creates an electric dipole moment that can perturb the ion channel signalling capability of any cells nearby. The advantage of this approach is its flexibility: quantum dots can be activated and deactivated simply by turning on and off the excitation light, and can also be selectively bound to specific biological targets by modifying their surface chemistry. The researchers demonstrated the remote switching of cellular activity in cultured prostate cancer cells on CdTe quantum dot films, as well as cultured neurons on CdSe quantum-dot films and CdSe quantum-dot probes under excitation at wavelengths of 430 nm and 550 nm, respectively. They observed that these effects began to appear at an intensity rate of 107 photons per square micrometre per second.