Two-photon absorbing water-soluble fluorescent probe as a near-neutral pH indicator

The dynamics of intracellular pH is believed to be crucial for understanding the regulation mechanism of many physiological functions. Of the several methods avaible to detmermine pH, optical methods have several advantages including rapid response time, high signal-to-noise ratio, noninvasive, and excellent pH sensitivity. Since the first use of trapped intracellular pH probe, 6-carboxyfluorecein, was described by Thomas et al., a large number of pH indicators have been reported. SEE DISCLOSUR