Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena & Jena University Hospital, Jena, Germany.
Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena & Jena University Hospital, Jena, Germany; Abbe School of Photonics, Faculty of Physics and Astronomy, Friedrich Schiller University Jena, Germany.
Biochem Biophys Res Commun. 2019 Sep 17;517(2):297-302. doi: 10.1016/j.bbrc.2019.07.080. Epub 2019 Jul 25.
The electrical membrane potential (V) is a key dynamical variable of excitable membranes. Despite the tremendous success of optogenetic methods to modulate V with light, there are some shortcomings, such as the need of genetic manipulation and limited time resolution. Direct optical stimulation of gold nanoparticles targeted to cells is an attractive alternative because the absorbed energy heats the membrane and, thus, generates capacitive current sufficient to trigger action potentials [1, Carvalho-de-Souza et al., 2015]. However, focused laser light is required and precise location and binding of the nanoparticles cannot be assessed with a conventional microscope. We therefore examined a complementary method to manipulate V in a spatio-temporal fashion by non-focused visible flashlight stimulation (Xenon discharge lamp, 385-485 nm, ∼500 μs) of superparamagnetic microbeads. Flashlight stimulation of single beads targeted to cells resulted in transient inward currents under whole-cell patch-clamp control. The waveform of the current reflected the first time derivative of the local temperature induced by the absorbed light and subsequent heat dissipation. The maximal peak current as well as the temperature excursion scaled with the proximity to the plasma membrane. Transient illumination of light-absorbing beads, targeted to specific cellular sites via protein-protein interaction or direct micromanipulation, may provide means of rapid and spatially confined heating and electrical cell stimulation.
细胞膜电位（V）是可兴奋细胞膜的关键动力学变量。尽管光遗传学方法在通过光来调节 V 方面取得了巨大的成功，但仍存在一些缺点，例如需要遗传操作和有限的时间分辨率。将靶向细胞的金纳米粒子直接用光刺激是一种有吸引力的替代方法，因为吸收的能量会加热细胞膜，从而产生足以引发动作电位的电容电流[1, Carvalho-de-Souza 等人，2015 年]。然而，需要聚焦激光，并且无法使用常规显微镜评估纳米粒子的精确位置和结合。因此，我们研究了一种通过非聚焦可见光闪光刺激（氙气放电灯，385-485nm，∼500μs）来以时空方式操纵 V 的互补方法超顺磁微珠。用全细胞膜片钳控制对靶向细胞的单个珠子进行闪光刺激会导致瞬时内向电流。电流的波形反映了由吸收的光引起的局部温度的一阶导数以及随后的热耗散。最大峰值电流以及温度偏移与靠近质膜的程度成正比。通过蛋白-蛋白相互作用或直接微操作将光吸收珠靶向特定细胞部位的短暂光照可能提供快速且空间受限的加热和电细胞刺激的手段。
