Here, we present an optical technique that can induce waves of calcium ion
concentration in live biological cells. Ca2+ waves were induced by femtosec
ond pulsed-laser illumination. Living HeLa cells were exposed to focused 14
0 fs pulses of 780 nm wavelength at 30 mW average power. Ca2+ waves were im
aged by fluorescence and were observed to propagate from the laser focal po
int inside the cell. Photoinduced generation of Ca2+ waves can be performed
at any point inside the cell, an improvement over previous mechanical or b
iochemical stimulation techniques. (C) 2001 American Institute of Physics.