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

为了提高光镊的捕获力，采用了可调谐的Ti：Sapphire和Cr。LiSAF激光器被开发，并且发现用两个相同的激光器的组合获得的环形图案光束轮廓是有效的。进行以下光镊的应用。为了直接研究核内动力学，用激光陷阱操纵基端离心的原丝体细胞的极度变形的核。结果表明，NT的染色质中存在缩短力，染色质和核膜之间可能不存在物理联系。为了研究伪足突起的机制，我们测量了细胞内的刚度和粘度的领先地区，主体，和尾随地区的位移振荡的细胞内颗粒驱动的光阱。结果表明：（1）在体部和尾部，颗粒分为“固定”和“自由”两类; 2)在机身和尾部区域，刚度或粘度没有差异，但在前部区域两者都急剧降低。为了研究其稳定机制，我们用激光微束照射横切暴露的微管，观察其长度的变化。神经炎中的微管通过以下方式稳定：1）在包括正端在内的局部部位停止解体，以及2）沿长度方向沿着减慢解体。

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.