本研究利用微機電系統製程（Micro-Electro-Mechanical-System, MEMS），成功設計製作3D立體微型磁箝，可以操縱奈米尺度的單一DNA分子，達到拉伸單一DNA分子之操縱，以觀察測量DNA分子之物理機械性質。

　　設計製作之3D立體微型磁箝包含：微型電磁鐵、磁性捕捉器、微流管道等元件。利用田口品質設計方法使磁性合金之電鍍最佳化，降低鍍面之粗糙度，並透過生化修飾，將單一DNA分子兩端分別鍵結直徑為2.8 μm與直徑為1.0 μm的超順磁性磁珠，其中一端之磁珠已經硫醇基修飾，另一端則無。兩端分別鍵結磁珠的單一DNA分子樣品經由蠕動式幫浦輸送到微流管道，當DNA分子到達操作區上方，經由電源供應器施予磁性捕捉器直流電流，產生磁場吸引鍵結磁珠之DNA分子至金表面，已經硫醇基修飾之磁珠與金表面產生共價鍵結，關閉磁性捕捉器之電流後，未經修飾硫醇基之磁珠懸浮在工作溶液中，依序分別施加直流電流給微型電磁鐵，產生磁場吸引懸浮之磁珠，達到拉伸DNA分子之多樣性操縱。微型電磁鐵可產生20pN以上的磁力，將單一DNA分子拉伸至它整個全長以上而不會伴隨有明顯的焦耳熱。DNA分子操縱實驗中，也拉伸了鍵結有兩條DNA分子的磁珠，而DNA也呈現出高度的非線性行為。

　　此3-D微型立體磁箝除了單一DNA分子之操縱外，仍有其他生物應用之潛能，可以將此操縱平台應用在不同之有機線材的研究，例如蛋白質或細胞之研究，透過磁珠鍵結細胞與施加磁場，來觀察細胞。應用此3-D微型立體磁箝操縱平台於生命科學與奈米科技領域。

　　This study designed and fabricated 3-D micromachined magnetic tweezers using MEMS（Micro-Electro-Mechanical-System）technology capable of manipulating a single DNA molecule. The key components, include 6 micro-electromagnets, a ring trapper, a fluidic channel and a gold-patterned surface that can be integrated to form a micromachined-based DNA manipulation platform. The micro-electromagnets can exert a magnetic force over 20 pN with little heating to extend a DNA molecule over the whole contour length.

　　One end of the DNA molecule was bound to a thiol-modified magnetic bead with a diameter of 1.0 μm. The other extremity of the DNA molecule was bound to an unmodified magnetic bead with a diameter of 2.8 μm. A syringe pump was used to transport the DNA sample into the micromachined DNA manipulation platform. Then, the magnetic beads tethered to the DNA molecule were attracted to the gold-patterned surface by the ring trapper. The thiol-modified magnetic bead was immobilized on the gold surface due to the Au-S covalent bonds. When the current of the ring trapper was turned off, the bead with non-specific binding was then suspended in the buffer solution. The suspended magnetic bead could be manipulated within the magnetic field generated by micro-electromagnets.

　　In conclusion, this novel DNA manipulation platform was used to observe the physiological behavior of DNA and investigate its physical properties. The proposed approach will offer a new tool for the field of nano-technology, which will make substantial impacts on development a new nano-scale materials and improve our understanding of intriguing structures.

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