有機光電平台在液體控制與細胞操作的應用

Abstract

傳統實驗室裡的生化反應流程被重新設計與實現在微小化的晶片上，目的在於增加生化反應速度、減少檢體的使用量以及操作過程能源的耗費。生物微粒的操作與流體的控制在微觀世界中扮演重要的腳色，多種技術如光學捕捉、電動與機械式的致動廣泛地被研究。光電整合技術的開發使用低光強度光源，同時消除複雜的製程、可動式元件以及電訊號控制。光電鑷夾與光電濕潤為此領域中兩項強大的工具，提供了操作細胞(或介電微粒)以及致動液態的水珠的功能。 在本篇論文中，我們提出了使用有機光導電材料TiOPc開發的光電鑷夾與光電濕潤來實現生化反應的流程。有機光導電材料的優點包含了無毒、低價、容易塗佈製造、有彈性、泛色度與高光敏感度。相較非晶矽( a-Si) 光電裝置的製造需要使用廠房中昂貴的電漿式增強化學氣相沉積(PECVD)，有機光電裝置可以使用實驗室中的旋轉塗佈與UV曝光製程來簡單製作。我們首先實現了TiOPc式的光電鑷夾，利用動態的光感應虛擬電極產生介電泳力來操作微粒與細胞。TiOPc式的光電濕潤被開發使用光感應虛擬電極改變固液介面的表面張力來控制在空氣或油中的液珠。最後，我們將TiOPc式的光電鑷夾與光電濕潤整合成單一晶片的有機光電平台，藉由應用特定的光電極圖案與不同頻率的電訊號調控，在高頻時(> 100 kHz)使用光電鑷夾操作微粒(或細胞)，而在低頻時(< 5 kHz) 利用光電濕潤搬運液珠。為了提升有機光電平台的效能，我們藉由減低TiOPc與介電層的厚度來增加光電鑷夾與光電濕潤操作微粒與液珠的能力。在目前的有機光電平台上，光電鑷夾可以產生2.7 pN的力使15 μm的微粒以速度18.9 μm/s移動，而光電濕潤可以在空氣或油中以4 mm/s的速度來操控液珠。我們開發的有機光電平台提供了整合微觀的生物微粒操作與宏觀的液體控制來實現生化反應流程的可能性。

Traditional biological reaction processes in the laboratory are redesigned and implemented in the miniaturized chips for increasing the reaction speed, reducing the amount of samples and lowering energy consumption. Bioparticle manipulation and liquid control play important roles in the microscale applications and are extensively researched with diverse technologies such as the optical trap, electrokinetic and mechanical actuations. Optoelectronic technologies are developed to use the low light power and eliminate complicated fabrications, moving parts and the complicated electrical connections. Optoelectronic tweezers (OET) and optoelectrowetting (OEW) are two powerful tools to provide functions of manipulating cells (or dielectric particles) and actuating liquid droplets.

In this dissertation, organic optoelectronic devices are developed by using titanium oxide phthalocyanine (TiOPc) as the photoconductive material for the implementation of OET and OEW devices. The advantages of organic photoconductive material include non-toxicity, low cost, easy coating fabrication, flexibility, panchromaticity and high photosensitivity. Comparing to amorphous silicon (a-Si) based optoelectronic devices fabricated by plasma enhanced chemical vapor deposition (PECVD) in the factory, organic optoelectronic devices can be easily manufactured with spin-coating and UV exposure process in the laboratory. We firstly achieve TiOPc-based OET which provides dynamic light-induced virtual electrodes to generate dielectrophoresis (DEP) force for manipulating microparticles and cells. The TiOPc-based OEW device is developed to use light-induced virtual electrodes to change the surface energy of the solid-liquid interface in the light illuminating location to actuate droplets in air and oil. Eventually, TiOPc-based OET and OEW are integrated to the organic optoelectronic platform which manipulates microparticles/cells and droplets on a single chip. By applying the specific optical patterns and the electrical signals with different frequencies, microparticles/cells are manipulated by OET in the high frequency region (> 100 kHz) and droplets are actuated by OEW in the low frequency region (< 5 kHz). The performance of the organic optoelectronic platform is improved by reducing thicknesses of TiOPc and dielectric layers to enhance OET and OEW forces. In the present organic optoelectronic platform, the OET force of 2.7 pN is generated to manipulate 15 μm microparticles with the speed of 18.9 μm/s and OEW can actuate droplets with the speed of about 4 mm/s in air and oil. Our organic optoelectronic platform provides the possibility of integrating bioparticle manipulation in microscale and liquid operation in larger scale to accomplish the biological reaction processes.