流動磁性粒子虛擬通道之實現

Abstract

隨著科技的進步，各領域的研究都朝向微小化發展，許多研究已經將研究主題進展至微米甚至奈米大小的尺度。目前透過微機電系統製程技術，已經可以將許多大型儀器設備的功能整合在一個釐米大小的晶片上。在生物醫學領域，這類的晶片被稱為微流道晶片，可以用來做混合、操作、傳輸及分離等功能。 近年來的相關研究都將微流道以隧道形式的微管道來設計，以方便磁性粒子的運輸及操作。這類屬於「實體」通道的微流道晶片通常需要藉由幫浦來推動液體流動及粒子/細胞運輸。在液體流動的過程中，包含粒子的溶液必須不斷地注入與排出，造成溶液與粒子的浪費。此外，阻塞及污染會導致晶片在使用壽命結束後必須拋棄。 使用「虛擬」通道來控制粒子可以避免上述的問題，本研究藉由使用金屬鎳建構虛擬通道微流道晶片來試圖解決上述問題。利用鎳的鐵磁性材料特性，可以用外加磁場將其進行磁化，使用磁化的鎳所產生之磁場建構出虛擬的「磁場牆」來引導磁性粒子。此外，在本研究中，使用玻片夾在含有磁性粒子的液體及有著鎳結構的晶片中間來預防液體與有晶片直接接觸。 藉由使用金屬鎳，本研究發展了一個新穎的微流道系統建構基礎，其中包含了蒐集型流道、運輸型流道以及功能型流道。本研究亦試圖藉由模擬來了解磁鐵的擺放排列對於磁性粒子的受力之影響。此外，磁性粒子的流速與不同尺寸或形狀流道的磁場強度之關係亦有探討。

With the trend towards miniaturization in many fields of research, many studies have advanced to research topics of the micrometer or even nanometer scale. The fabrication technology for micro-electro-mechanical systems (MEMS) allows us to integrate the functions of a large instrument into a centimeter-sized chip. In biomedical science, such a chip which is called microfluidic chip can be used for mixing, manipulation, transport and separation, etc. Recent studies have devised microfluidic channels in the form of a tunnel, making it relatively easy to transport and manipulate beads. Chips with ‘‘substantial’’ channels normally require pumps for fluidic flow and particle/cell transportation. During operation the fluid flows; therefore, constant inputs and outputs of the solution containing beads are required, leading to waste of the solution and beads. Also, resulting from the clogging and contamination, the chip has a certain operational lifetime. Utilizing ‘‘virtual’’ channels to control beads can avoid the above-mentioned problems. our work attempts to solve the above problems by using nickel to construct the virtual channels in microfluidic chips. With its own ferromagnetism, nickel can be magnetized using an external magnetic field. Additionally, the magnetic fields produced by nickel allow us to form virtual ‘‘walls’’ in order to guide the magnetic beads. In this work, a glass substrate is sandwiched between the liquid containing magnetic beads and the chip with nickel structures, preventing the liquid from directly contacting the nickel. By using nickel, this work develops the building blocks for a novel microfluidic system, including the collecting channels, transporting channels, and function channels. This work also attempts to understand how the placement of the magnet affects the force exerted on magnetic beads by simulation. Furthermore, the correlation between the flow rate of the magnetic beads and the magnetic flux density for channels of different dimensions or geometrical configurations is obtained.