Optically patterned cell growth applied to the directed evolution of a GFP-based glucose sensor

There is a great deal of interest in the development of biosensors based on green fluorescent protein. Several such sensors have been developed for targets ranging from calcium ions to small peptides . Such sensors have several advantages for certain types of applications. First, the sensor itself is a single molecular unit that can be grown and produced in relatively large quantities. Second, it is nontoxic and, since it uses fluorescence can be sensitive to the single molecule level. Finally, it can be expressed in almost any type of cell, allowing either for a living biosensor that regenerates itself or internal monitoring of cellular functions.