以液體介電泳和介電濕潤建造異質且仿生之細胞培養微結構

Abstract

本研究利用電控微流體技術得以在微小尺度下利用電訊號同時控制多種液體移動的特性，配合使用含有不同種類細胞的水膠預聚物溶液，以及事先設計好的仿生電極圖案，將水膠預聚物溶液排列成相對應之圖形後使之交聯，產生具有固定邊界的細胞培養微結構，並進行培養，探討細胞培養微結構圖案化以及多種細胞共培養對細胞表型之影響，以證實此技術具有實現人體器官晶片並取代活體做為藥物測試樣本之潛力。現今已有許多人體器官晶片或是仿生微結構的建造技術被提出，而這些研究不約而同地著重於重現體內實際組織形態之重要性，如何製造複雜的細胞組成並進行仿生圖案化，便成為一大課題。而本研究使用電控微流體技術來建造異質且仿生之三維細胞培養微結構，便是希望提出一個可以同時排列多種含有細胞的生物材料之生物製造方法。 本研究使用之水膠材料包含poly(ethylene glycol) diacrylate (PEGDA)以及gelatin methacrylate (GelMA)，皆具光交聯性質，在照射紫外光後會由液態轉為固態，此特性使得電控微流體技術得以在其為液態時運用電訊號操控之，並在曝光後產生具有固定形狀之水膠微結構。本研究將針對不同種類的水膠預聚物溶液、尺寸及操控環境探討電控微流體驅動不同液體的工作原理，並以特殊電極形狀排列含有螢光粒子及細胞之水膠預聚物溶液來展示此技術同時圖案化多種液體之能力。本研究除了以不同寬度的細胞培養微結構來驅使細胞產生方向性的生長、研究細胞生長環境之物理限制對其之影響外，也設計仿人類肝臟小葉的電極形狀，同時排列含有不同種類細胞---包含人類臍帶內皮細胞(HUVEC)、人類肺臟纖維母細胞(HFL1)、人類肝癌細胞(HepG2)---成仿生圖形之後，以建構模擬人體中真實組織形態且具有多種細胞排列的培養微環境並在培養後進行染色與表型分析。

Electromicrofluidics (EMF), simultaneously and flexibly controlling multiple fluids with appropreiate electrical signals, is investigated to pattern various cell-laden hydrogel pre-polymers into in-vivo-like microenvironment concurrently in a single fluid manipulation step. By using photo-crosslinkable hydrogels and pre-designed electrodes with biomimetic patterns, in-vivo-like cell-laden microstructures with defined boundaries can thus be constructed after hydrogel polymerization, which can be harnessed to analyze the influence of the patterned microenvironment and cell multi-culture towards cell phenotype. Among recent biofabrication techniques reported to develop so-called “organs-on-chips”, the trends of in vitro tissue reconstruction emphasize on its consistency towards the in-vivo anatomical microenvironment. Therefore, to establish microstructures with various cells patterned into biomimetic arrangement becomes an issue to be addressed. In this view, EMF was adopted as a powerful tool to reconstruct 3D heterogeneous and biomimetic cell culture scaffold in a relatively straightforward manner. In this thesis, two kinds of photo-crosslinkable hydrogels, poly(ethylene glycol) diacrylate (PEGDA) and gelatin methacryloyl (GelMA), were adopted as the manipulated fluids and patterned into pre-designed configurations on our EMF platform. After UV exposure, hydrogel pre-polymers were polymerized and thus formed hydrogel-based microstructures with concrete boundaries and in desired shapes. Different hydrogel pre-polymers were manipulated in altered dimensions and ambience in order to examine the working principle of hydrogel pre-polymer manipulations on the EMF platform. Fluorescent-particle-laden and cell-laden hydrogel pre-polymers were patterned on the platform into pre-designed arrangement by applying electric signals, demonstrating the ability of multiple fluids manipulation with EMF techniques. Human hepatic lobule was selected as the in-vivo model of this research, as human umbilical vein endothelial cell (HUVEC), human lung fibroblast (HFL1), and human hepatocellular carcinoma (HepG2) were added into hydrogels to perform cell multi-culture and to conduct further investigations.