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Volume 12, Number 2-4, December 2004


Small Molecule‐based FRET Sensors Which Enable Ratiometric Imaging of Living Cells

Kazuya Kikuchi

(Summary)
Fluorescence resonance energy transfer (FRET) has been used extensively as the designing principle for fluorescent sensor molecules, in both GFP based sensors and synthetic organic sensors. One of the most significant advantages of designing a sensor molecule with FRET modulation is that it can enable ratiometric measurement in living cells. The design strategy for the development of small molecular FRET sensor is described; it is based on changing the two factors in the F･rster equation: donor and acceptor distance and overlap integral of donor emission and acceptor absorbance spectra. A careful design strategy is necessary in designing small molecule‐based sensor molecules in order to avoid close contact of donor fluorophore and acceptor fluorophore in aqueous solution. Furthermore, a strategy to design FRET sensor molecules to monitor cellular activity of protein tyrosine phosphatases with modulating overlap integral is introduced.