jo7019898_si_001.pdf (2.5 MB)
Optically Switchable Chelates: Optical Control and Sensing of Metal Ions
journal contribution
posted on 2008-01-04, 00:00 authored by Tomoyo Sakata, David K. Jackson, Shu Mao, Gerard MarriottThis study introduces new concepts in the design, synthesis, and in vitro and in vivo characterization,
manipulation, and imaging of organic chelates whose association with metal ions is rapidly and reversibly
controlled by using light. Di- and tricarboxylic group bearing photochromes, nitrobenzospiropyran
(nitroBIPS), undergo rapid and reversible, optically driven transitions between their spiro (SP) and
fluorescent merocyanine (MC) states. The MC state of nitroBIPS-8-DA binds tightly to various metal
ions resulting in specific shifts in absorption and fluorescence, and the dissociation constant for its
Gadolinium complex in water is measured at ∼5 μM. The metal-bound MC state is converted to the
weaker-binding SP state with use of 543 nm light, while the SP to MC transition is complete with use
of 365 or 720 nm (2-photon) light within several microseconds. Fluorescence imaging of the MC state
of nitroBIPS-8-TriA was used to quantify the rate and efficiency of optical switching and to provide a
real-time readout of the state of the optically switchable chelate within living cells.