An Integrated Microfluidic Device for the Continuous Sampling and Analysis of Biological Fluids Author ： Jeffrey D.Zahn, Ajay A Deshmukh,Alexandros P.Papavasiliou,Albert P.Pisano and Dorian Liepmann Wun-Hao Wu ( 吳文豪 ) Reporter: Wun-Hao Wu ( 吳文豪 ) 10/17, 2007

Abstract First: introduce the device Second: the device work principle Third: question

Packaged Microneedle device

Microneedle It is permeable to small molecular weight (MW) molecules, yet excludes large MW compounds such as proteins. Why they devise this some holes (they call microdialysis membrane)? Because, it can reduce large molecular weight proteins adsorbing on the surface of the glucose sensor.

Fabrication for Needles back ▲

▲ Gate valve First: Left Electrolysis bubbles are opened. Second: Right Electrolysis bubbles are opened and Left Electrolysis bubbles are closed. Then ： Right bubbles are more and more. Third ： Left Electrolysis bubbles are opened again. Then ： Left bubbles are more and more. One entire cycle, from fully open to fully closed an back to fully open, takes on average around 120 seconds.

▲ back ▲ Glucose sensor

Multichannel Pumping Pump 左邊十字微結構當 水從左邊來時，可 阻擋水通過；右邊 方塊形結構當水從 右邊來時可以推開 方塊而通過。 Pump 2 Valve opens work

2. work principle 1. 首先從人的血管取得血液進入微探針裡，經過微結構設計過濾掉一些大分子量的蛋白質。 2. 待感測的液體進入葡萄糖感測器，量出電流的變化後。 3. 啟動 pump(1) 且 gate valve 打開，將 PBS 注入葡萄糖感測器中清洗。 4. 關閉 pump(1) 打開 pump(2) 且 gate valve 打開將葡萄糖溶液注入到葡萄糖感測器中恢復到原來的 濃度。 5. 最後 pump(3) 將胰島素經過探針進入人體血液中。 PBS(pump1) Stock concentration of glucose(pump2) Insulin(pump3)

3. Question The blood is in the needle’s channel,the proteins can adsorb on the microdialysis membrane. That proteins maybe block the microfluidic channel. It doesn’t tell us how to remove these proteins. The Gate Valve creates the actuation bubbles. Maybe bubbles can move into the microfluidic channel. They also block it. They don’t tell us this chip how to work. I suspect that some device can’t work. If they have some picture to show that action are step by step. I will believe it.