近年來，空心微針已被製造，並且應用於即時(point-of-care)經皮生物感測器或藥物輸送。與實心微針相比，空心微針的優點有二：一為允許更大藥物量被輸送，另一個為透過連接編程的微型幫浦，可以持續地主動控制藥物輸送。雖然大部分關於空心微針的研究主要為經皮藥物輸送裝置，但它們也可以作為微全分析系統(micro total analysis system, μTAS)以評估生物樣品，例如用於葡萄糖檢測的微型葡萄糖感測器、用於萬古黴素的微針-光流體(optofluidic)的生物感測器，以及用於監測谷氨酸的雙成份微針生物感測器。
本研究以微過濾的方式製作高分子空心微針貼片，首先製作出具有上下通孔的金字塔狀微結構陣列之PDMS模具，將模具放在濾紙上，並滴上chitosan溶液，開始抽氣過濾，一小時後可製作出chitosan空心微針。接著探討影響微針成形的因素，包括過濾時間、濾紙孔徑大小、高分子濃度，以及測試微針機械強度、穿刺豬皮等微針性質，也觀察微針在組成豬皮成分的明膠固化物中，其溶解形貌隨時間之變化。實驗結果顯示，所製作的空心chitosan微針並沒有足夠的強度能穿刺豬皮，可透過在空心微針內填入PVP，使成PVP-chitosan複合微針解決強度不夠的問題。而在親水性濾膜表面旋塗一層疏水性PDMS薄膜，可以製備流體僅由微針內空腔流通，而不由微針陣列間濾紙流過的微針貼片。

In this study, we proposed and demonstrated a one-step process to fabricate the polymer hollow microneedles (MNs) by filtration. The polydimethylsiloxane (PDMS) mold with funnel-like cavities with through holes was first created, which was placed on top of a filter paper. A droplet of chitosan solution was dispensed on top of the mold and vacuum was turned on. Different processing parameters such as filtration time, solution concentration, vacuum power, etc. are discussed. It was found that the polymer hollow MNs were formed after 1-hr filtration, followed by 12-hr drying. After spin coating the PDMS film on the hollow MNs array, a MNs patch can be prepared by passing the fluid only through the MNs. However, the MNs as fabricated don’t have sufficient mechanical strength to penetrate the porcine skin. The PVP-chitosan composite MNs were made by filtration. The PVP-chitosan composite MNs are strong enough to penetrate the pigskin.

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