經皮藥物輸送為新興起且具有潛力的給藥方式，不需經肝臟初步代謝且能達到無痛給藥，而微針貼片便可用於經皮藥物的輸送。然而由於人體皮膚並非一個平整平面且有大小不一的曲率變化，因此微針須具備一定的機械強度且高度方能刺穿表皮層。目前有關微針陣列之相關文獻用蝕刻矽晶圓的方法製備out of plane的微針(微針垂直於晶圓表面)，其高度最高為接近300μm。另外，雖然可利用光阻劑製作高於300 micron的微針，但製作程序相對的繁瑣。
本研究希望藉由乾濕蝕刻的兩階段方式，製備出高度達600微米的矽基材微針晶片作為母模，以二甲基矽氧烷(polydimethylsiloxane,PDMS)鑄造負向模，應用於鑄模法製備高分子微針。由實驗結果發現，雖然可以成功地製備出第一階段微針，但在第二階段濕蝕刻時，因金屬遮罩覆蓋均勻度不佳，造成蝕刻液滲入遮罩內破壞微針結構。若以CNC雕刻機製備微柱結構或濕蝕刻製備出的燭台結構，則可以PDMS鑄造負向模後，與第一階段微針之負向模貼合，灌入高分子溶液待其乾燥取出，得到高度達600微米的高分子微針陣列。

Transdermal drug delivery is a new emerging and potential mode of administration. Since the transdermal route bypasses the first-pass effect of the liver and is painless. The microneedles patch is one of the transdermal drug delivery method. Because human skin is not a flat plane with changing curvature, a certain degree of mechanical strength and height for the microneedles to pierce through the epidermis is required. In the literature, it’s rare to find the height of microneedle arrays(out of plane) larger than 300micron. In some cases, they were fabricated by silicon etching or using photoresist which is a relatively cumbersome process.
In this study, we intended to fabricate silicon microneedle master mold with height larger than 600 micron by using wet etching and dry etching, followed by obtain the PDMS negative mold to produce polymeric microneedles. The results showed that, although the sharp microneedles were produced, they were destroyed during formation of candleholder-like structure by wet etching. This is becomes of the poor coverage of the masking material. The candleholder-like structure was then obtained separately by wet etching process and CNC micromaching. The negative molds of microneedles and candleholder-like structure were produced and bonded together and the 600 micron high polymeric microneedles were then obtained by casting PVP and drying.

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