Green fluorescent proteins as optically controllable elements in bioelectronics

A single-biomolecule optical toggle switch is demonstrated based on a mutat ed green fluorescent protein (GFP). We have exploited molecular biology tec hniques to tailor the GFP molecular structure and photophysical properties and to give it optically controlled bistability between two distinct states . We present optical control of the fluorescence dynamics with two laser be ams at 476 and 350 nm down to the ultimate limit of single molecules. These results indicate that GFP-class fluorophores are promising candidates for the realization of biomolecular devices such as volumetric optical memories and optical switches. (C) 2001 American Institute of Physics.