Iwanaga S, Smith N I, Fujita K, Kawata S
Opt Express. 2006 Jan 23;14(2):717-25. doi: 10.1364/opex.14.000717.
We demonstrated stimulation of Ca(2+) in living cells by near-infrared laser pulses operated at sub-MHz repetition rates. HeLa cells were exposed to focused 780 nm femtosecond pulses, generated by a titanium-sapphire laser and adjusted by an electro-optical modulator. We found that the laser-induced Ca(2+) waves could be generated over three orders of magnitude in repetition rates, with required laser pulse energy varying by less than one order of magnitude. Ca(2+) wave speed and gradients were reduced with repetition rate, which allows the technique to be used to modulate the strength and speed of laser-induced effects. By lowering the repetition rate, we found that the laser-induced Ca(2+) release is partially mediated by reactive oxygen species (ROS). Inhibition of ROS was successful only at low repetition rates, with the implication that ROS scavengers may in general be depleted in experiments using high repetition rate laser irradiation.
我们展示了通过以亚兆赫兹重复率运行的近红外激光脉冲对活细胞中的Ca(2+)进行刺激。将HeLa细胞暴露于由钛宝石激光器产生并由电光调制器调节的聚焦780 nm飞秒脉冲下。我们发现，激光诱导的Ca(2+)波可以在重复率的三个数量级范围内产生，所需的激光脉冲能量变化小于一个数量级。Ca(2+)波的速度和梯度随重复率降低，这使得该技术可用于调节激光诱导效应的强度和速度。通过降低重复率，我们发现激光诱导的Ca(2+)释放部分由活性氧(ROS)介导。仅在低重复率下ROS抑制才成功，这意味着在使用高重复率激光照射的实验中，ROS清除剂通常可能会耗尽。
