本研究主要目標是發展一套簡易並具有彈性之微液滴產生與融合方式，使用壓力與微流道的幾何特性取代複雜的電氣式驅動，以利生醫晶片上的各種運用，避免電氣式因電磁場作用容易影響檢測結果，或破壞生物分子的各種問題；並且能夠有效改變產生微液滴的大小，快速產生定量與融合所需不同成分比例與體積的微液滴。
主要的觀念源自於水龍頭滴出水滴的觀念–表面張力與重力的相互關係；當水滴所受到的重力大於表面張力時，水滴會被重力向下拉扯直到斷面出現，因此產生水滴。在本研究的晶片中以氣壓來重現重力場，搭配疏水性漸縮與漸擴的微流道，以連續穩定的氣壓方式驅動，切割產生微液滴並消除衛星液滴。由於水龍頭滴出的液滴體積大小並非固定，勢必和液體的黏滯係數、重力場大小、表面張力大小以及液體流速等相關，因此只要改變某一參數就會得到不同大小的液滴，如此觀念也可以運用到本研究的晶片上，達到控制微液滴大小的效果。
目前已達成的功能為：純粹藉由控制注射幫浦推擠液體流速，以及空氣壓縮機所產生的氣壓，便可得到體積0.5 至50 nl的微液滴，並可初步將兩顆產生之液滴融合在一起。未來目標則是建構平行化陣列式液滴產生操控系統，相信將可滿足生醫自動化檢測系統在成本與功能上迫切的需求。

This paper presents a droplet generation scheme that employs constant pumping sources to periodically digitize a continuous liquid flow into nanoliter segments with desired volumes. In this scheme, a constant-pressure air flow assisted by channels with certain geometries is used to break a constant-rate liquid flow and dispense the separated segments. Simply by adjusting the air pressure and liquid flow rate, droplets with desired volumes can be generated. In the prototype demonstration, the droplet generators are made of PDMS microfluidic channels with preferred geometries and surface properties. 3-way junctions integrated with converging/diverging channels are utilized to guide the flows. Through the discretization sequence, liquid is temporally held by the channel to facilitate the cutting executed by air flow. Based on this scheme, it has been demonstrated that a continuous liquid flow can be split into segments with volumes ranging from 0.5 to 50 nanoliters. In addition to air pressure and liquid flow rate, the resulted droplet volumes are also found to be affected by channel geometries. As such, this adjustable droplet generation scheme opens up a new class of metering and manipulation prospects for microfluidic applications.

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