應用交疊流道的高通量液滴濃度調配晶片

High-Throughput Droplet-Concentration Generation Chip with Overlapping Microchannels

賴皓煒(Hao-Wei Lai)

指導教授 ： 楊鏡堂

國立臺灣大學/工學院/機械工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10238

摘要

本研究致力於發展出一高通量液滴濃度調配晶片，以控制流率作為液滴濃度及生成頻率的調控方式，使單一晶片能產生多種濃度的液滴陣列。此晶片能調控生成多種濃度液滴，且液滴通量能達到每秒1000顆。在應用上有助於提高細胞對藥物反應的檢測效率。
本研究將流體液滴操縱分為三個步驟，分別由不同的流道結構達到目的，第一步為液滴生成，第二步為液滴分割，第三步為液滴融合。第一步採用T型流道生成液滴，控制液滴的生成頻率及原始尺寸。第二步用十字交疊流道進行液滴分割，來自兩入口的液滴在進入交疊流道前會匯入更多連續相液體受到不同程度加速，兩方向的流速差會改變液滴的轉向傾向，用流速差能操縱液滴分割尺寸。第三步用漸擴漸縮型流道使分割後的液滴兩兩融合，此流道末端藥滴與緩衝液滴融合為目標濃度藥滴。實驗操作範圍內每秒生成50顆目標濃度液滴，而理論生成頻率可達每秒1000顆，高通量下運用可使藥物檢測單位時間樣本數增加，檢測效率高。本研究的操控範圍內最終藥滴的濃度能在原始濃度的35~44%及56~65%進行操縱。
研究結果顯示在交疊區域兩入口流速的差值會造成液滴分割，高流速入口的液滴會被分割，來自低流速入口滴液滴不分割維持直行，而兩方向入口流速的差異愈大會造成被分割的液滴分往側向的比例愈高。在瞭解液滴的分割行為部分，先著手十字交疊流道的流場情形，將一方向連續相流體染色，並觀測交疊區域的濃度分布，並用數值模擬軟體進行連續相的流場模擬，綜合兩者資料推斷此區液體的流向，進一步推測液滴的轉向行為與流場的關係，解釋兩流向的流速差所造成的分割尺寸差異。

關鍵字

濃度調配 ； 微流體系統 ； 交疊流道 ； 高通量

並列摘要

The purpose of this paper is to develop a high-throughput droplet-concentration generation chip. The droplet concentration and generation frequency of the chip can be controlled by the import flow rate, which enables a single chip to produce a variety of concentrations of droplets array. In my study, the chip can generate a variety of concentration drops, and drops flux can reach 1000 per second, which helps improve efficiency of detection of cellular response to drugs in practice.
The process of fluid droplet operation utilizing different flow channel structures can be divided into the following three steps: droplet generation, droplet spilt, and droplet fusion. At first, we use the T-junction to generate droplets. Droplet generation frequency and its original size are determined in this step. Then, the second step is carried out by using an overlapping channel. Drops from two directions will import more continuous phase liquid subject to different velocity before entering the overlapping channels. The droplets are split in the overlapping channels. The differences of velocity between droplets will change their steering tendency, and so we can manipulate droplet segmentation size through the difference of the flow rate. In the third step, we use the symmetrical coalescence chamber to merge the droplets. Droplets of drug and buffer combine into the target concentration droplets in this step. In the operation range of the experiment, we can generate 50 target droplets per second, while the theoretical generation frequency can be up to 1000 drops per second. The use of high-throughput drug testing can increase the number of samples per unit of time, and improve detection efficiency. In our paper, the final concentration of droplets can be manipulated under 35% to 44% and 56% to 65% of the original concentration.
The result shows that the differences of velocity of two inlets can spilt the droplets. The droplets from high flow-rate inlet are split, while the droplets from low flow-rate inlet remains straight. The higher the velocity difference between the two directions inlet flow rate is, the higher the ratio of steering volume of the splitting droplets is.
This study combines experimental observations and simulation of flow field, and explain the behavior of the droplets by the results of them. It further explains the relationship between droplets split ratios and inlets velocity difference.

並列關鍵字

Concentration generation ； Microfluidic ； Overlapping microchannel ； High-throughput

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