Paper
19 June 2003 Stimulation of living cells by femtosecond near-infrared laser pulses
Shigeki Iwanaga, Nicholas I. Smith, Katsumasa Fujita, Tomoyuki Kaneko, Masahito Oyamada, Tetsuro Takamatsu, Satoshi Kawata, Osamu Nakamura
Author Affiliations +
Abstract
We have demonstrated that intracellular Ca2+ waves in a living HeLa cell can be induced by femtosecond near-infrared laser pulses. In this paper, we present the results of investigation on the process of the Ca2+ wave generation using pharmacological methods to determine generation mechanisms. A mode-locked Ti:Sapphire laser (780 nm, 80 fs, 82 MHz) was used as a wave-triggering light source. The laser beam was focused into HeLa cells by using a water immersion objective lens (NA 0.9). Ca2+ waves were visualized by using a fluorescent Ca2+ indicator (Fluo-4) and monitored by a fluorescence microscope. Three mechanisms for the Ca2+ wave generation were considered; (1) Ca2+ flow into cells by destruction of the cell membrane, (2) mechanical stress by shock waves associated with the laser absorption, and (3) the leaking of Ca2+ through the destruction of intracellular Ca2+ stores. To investigate the mechanisms, we have performed experiments to determine the dependence of the probability of Ca2+ wave generation with two kinds of extracellular solutions; (a) a Ca2+ free extracellular solution (by use of EGTA), and (b) a solution containing U-73122 to inhibit the response to shockwave-based mechanical effects. From these experimental results, we can conclude the main mechanism of Ca2+ wave generation by laser irradiation is due to the leaking of Ca2+ through the destruction of intracellular Ca2+ stores.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shigeki Iwanaga, Nicholas I. Smith, Katsumasa Fujita, Tomoyuki Kaneko, Masahito Oyamada, Tetsuro Takamatsu, Satoshi Kawata, and Osamu Nakamura "Stimulation of living cells by femtosecond near-infrared laser pulses", Proc. SPIE 4978, Commercial and Biomedical Applications of Ultrafast Lasers III, (19 June 2003); https://doi.org/10.1117/12.478591
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Cited by 3 scholarly publications.
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KEYWORDS
Calcium

Femtosecond phenomena

Laser irradiation

Ions

Luminescence

Microscopes

Absorption

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