懸浮磁性粒子非實體通道系統之設計、製作與特性量測

Abstract

透過微機電製程製作的微流道系統結合磁性粒子在生物醫學和化學領域被廣泛應用，如蛋白質篩選、細胞分離、分子操控等等，大大地縮減過去傳統實驗室做生化分析所需的成本和時間。現今的微流體晶片仍以「實體」微流道為主，也就是在製程最後步驟會將流道上蓋和密封，使用流道來侷限住流體。本篇論文主旨就是設計並製作出一個無側壁和上蓋的磁性粒子專用之「非實體」通道，可以在靜態溶液中操控磁性粒子，相較於傳統實體微流道有製程簡易、不須使用微幫浦和閥門以及可以彈性地自由改變通道的幾何形狀等優點。 我們使用面型微加工技術在以矽基板為主體的晶片上製作出厚度20 μm鎳金屬條，並以二氧化矽蝕刻液蝕刻過之不同厚度蓋玻片覆蓋在晶片之上，簡易的非實體通道結構於是形成。將稀釋過的磁性粒子溶液滴在我們的元件之上，並透過外加釹鐵硼強力磁鐵操控之。 我們觀察、記錄和分析磁性粒子通過鎳金屬條的情形，並發現當蓋玻片厚度小於60 μm以下時，元件屏障和導引磁性粒子的效果最好。我們還將兩片晶片擺在一起排列形成不同角度的夾角與不同寬度的開口做測試。實驗結果發現鎳金屬條夾角30° ~ 90°導引磁性粒子的效果最好，而開口寬度大於300 μm磁性粒子通過開口時較為順暢。

Compared to the conventional laboratory, it saves a lot of costs and time to do biochemistry analysis through Microfluidic channel systems. Microfluidic channel systems, which are made from MEMS fabrication, combining with the magnetic beads are widely applied in the biomedical and chemistry fields such as protein screening, cell separation and molecular manipulation. Today’s microfluidic chip is mostly the “real entity” of the microfluidic channel systems, which seals up the upper cover of the channel to confine the fluidic body at the last step of the fabrication process. The main purpose of this thesis is to design and fabricate a magnetic-bead-specified “virtual” channel that lacks the side wall and the upper cover, which can be used to manipulate magnetic beads in static fluid. This design also brings the advantages; for examples, the fabrication process is much easier through the “virtual” channels and the channels do not need to use pumps and valves to operate the system in comparison to the conventional microfluidic channels. To make a simple virtual channel structure, we electroplated nickel straps with thickness of 20 μm on the chip of the silicon substrate by using Surface Micromachining technique and put different thickness of the cover glasses etched by BHF (buffered hydrofluoric acid) on the top of the chips. Then, the diluted solution of the magnetic beads is dripped on the devices and is controlled by the strong magnet which applied beside. After our observation of results of the magnetic beads passing through the nickel straps, we found out that the devices which trapped and diverted the magnetic beads having the best effect when the beads pass through the cover glasses under 60 μm thick. Furthermore, we tested by putting two chips in order to make different angles and different widths of the opened side. The results showed that the magnetic beads have the best effect when the angle of the nickel strap is 30°~90° and the magnetic beads can pass easier when the width of the opened side is larger than 300 μm.