微渦漩應用於箝制細胞之研究

Abstract

對於細胞研究，箝制懸浮的細胞是相當重要地。此研究介紹ㄧ個震盪的微尺度懸浮平板，其啟動機制依據羅倫茲力理論，在微流體下產生一相對應的微渦漩來抓取生物微粒子。相對於其他的研究，此微流體元件的特點是能使微粒子隨著流場流經此無阻礙的區域，進而可控制去抓取及釋放微粒子。元件製程利用微機電系統傳統的微影技術，並且藉由元件結構參數的分析來幫助設計一個好的箝制微流體元件。在箝制力學方面的研究係使用注射針筒注射十微米大小的聚合微粒子於流道中的微箝制器上方。此時增加背景流場流速直至被箝制住的抗體被沖刷走，藉由背景流速即可推算出此微振動平板所造成微渦漩之箝制力。 結果顯示可箝制微粒子之最小電壓約為2伏特(peak to peak)。且在電壓7伏特(peak to peak)下，此微渦漩可箝制微粒子於背景流速達到140微米/秒。此箝制力大小在十的負12次方牛頓力範圍內，並且和微渦漩轉速成線性關係。當微粒子被替換成十奈米大小的抗體時，在電壓7伏特(peak to peak)下，可箝制抗體之背景流速則達到1680微米/秒。此力學量測方式有效的控制箝制或釋放微粒子和巨分子。研究團隊相信這些特性是前所未見的。

Trapping of suspended cells is fundamentally important for cellular studies. This work presents a suspended oscillating micro-plate, actuated by Lorentz force law, and generated a pair of counter-rotating micro-vortices to trap bioparticles. In contrast to other approaches, this microfluidic device allows bio-particles to flow freely through unobstructed region, trapped, and controlled released. Fabrication methods utilized conventional lithography, and the parametric analysis of the structure is helpful to design the appropriate microfluidic device for trapping. Trapping study used polystyrene particles (10μm) injected into the PDMS channel by a syringe pump. By increasing the background flow velocity, controlled release of the trapped particle is demonstrated. Results show that the minimum voltage can be applied to trap particles around 2 Volts (peak to peak), and at 7Vpp input voltage the micro-vortices can trap the particles under 140μm/s background flow. The trapping force is in pico-Newton range, and varies linearly with the flow. When bioparticles are replaced with antibodies, at 7Vpp input voltage the antibodies can be trapped under 1680μm/s background flow. This hydrodynamic approach should be useful for controllable trap/release of bioparticles and macromolecules. The authors believe this to be the first account of having these features.