Development of Intense Optical Tweezers for Application to Internal Structural Analysis of Living Cells

为了增加光钳的捕获力，可调谐掺钛蓝宝石和铬。研制了LiSAF激光器，发现用两个相同的激光器组合得到的环状花纹光束轮廓是有效的。开展了光镊子的以下应用研究。为了直接研究核内动力学，我们用激光诱捕技术对极变形的碱基离心质子线细胞的核进行了操作。结果表明，NT的染色质中存在缩短力，染色质与核膜之间可能不存在物理联系。为了研究中性粒细胞运动中伪足突起的机制，我们测量了由光学陷阱驱动的振荡细胞内颗粒的位移在前导区、主体和拖尾区的细胞内硬度和粘度。我们发现：1)在虫体和拖尾区，颗粒分为固定种群和自由种群。2)在体区和后区，硬度和粘度没有差异，但在前导区，两者都显著降低。为了探讨它们的稳定机制，我们用激光微束照射暴露的微管，并观察它们的长度变化。神经炎的微管通过以下方式稳定下来：1)停止局部的分解，包括正端；2)减缓沿长度的分解。

In order to increase the trapping forces of optical tweezers, tunable Ti : Sapphire and Cr. LiSAF lasers were developed and it was found that Donut patter beam profile obtained with a combination of two identical lasers was effective. The following application of optical tweezers was carried out. For the direct investigation of intranuclear dynamics, extremely deformed nuclei of basipetally centrifuged protonemal cells were manipulated by the laser trap. It was concluded that a shortening force was existing in the chromatin of the NT and that probably no physical link existed between the chromatin and the nuclear envelop. To investigate the mechanisms underlying pseudopod protrusion in locomoting neutrophils, we measured the intracellular stiffness and viscosity in the leading region, main body, and trailing region from displacements of oscillating intracellular granules driven with an optical trap. We found 1) in the body and trailing region, the granules divided into a "fixed" population and a "free" population. 2) In the body and trailing region, there was no difference in stiffness or viscosity, but both were sharply lower in the leading region. To investigate their stabilization mechanism, we transected the exposed microtubules by laser microbeam irradiation and observed their length changes. Microtubules in neuritis were stabilized by 1) stopping disassembly at local sites including the plus ends, and 2) slowing disassembly along the length.