奈米科技的蓬勃發展之下，皮膚受到美容或保養產品中奈米粒子暴露的風險也相對地提高，目前已有研究結果顯示，奈米微粒確實可直接穿透皮膚進入真皮層，隨著奈米科技進步，各式各樣不同型態奈米粒子被設計出來，進一步探討不同形狀奈米粒子於皮膚穿透度上的影響更顯其重要性。
本研究以奈米金球及金棒作為奈米粒子探討皮膚之穿透性，引入Poly(ethylene glycol) 2-mercaptoethyl ether acetic acid (SH-PEG-COOH)於奈米金與化學促進劑之間，PEG一端是硫基，硫基與金具有極佳的鍵結能力，除了可提高修飾後的奈米金粒子之穩定性，其具有改變角質層表面結構之作用；PEG另一端則可與皮膚穿透性之化學促進劑(Oleylamine, OAm)結合，探討PEG與OAm鍵結穿透能力上之差異，並以核磁共振光譜儀及傅利葉紅外光儀，確認高分子材料之結構，而金表面修飾以穿透式電子顯微鏡、紅外線光譜、傅利葉紅外光儀及表面電位上判別。此外，為了有效利用共軛焦顯微鏡分析奈米金粒子之穿透性，近一步將Fluorescein isothiocyanate (FITC) 修飾在奈米金表面。
由於奈米金粒子具有消光效應，僅使用螢光顯微鏡作為判斷依據是無法準確地知道奈米金粒子的穿透情形，因此結合共軛焦顯微鏡及穿透式電子顯微鏡觀察組織切片，綜合兩者之實驗結果而得奈米金粒子的形狀、改質前後於大鼠皮膚穿透之效率、途徑及累積情形。

Nanoparticles are being used in multiple applications, ranging from biomedical and skin care products (e.g., sunscreen) through to industrial manufacturing processes (e.g., water purification). The increase in exposure has led to multiple reports on nanoparticle penetration. However, the correlation between gold nanoparticle shape and its penetration with chemical enhancers through the skin is poorly understood.
Purpose of the present work is to study the effect of particle shape and surface modification on penetration of gold nanoparticles through rat skin. Besides flexible shape adjustment, the great popularity of gold nanoparticles originates also from their straightforward surface modification by formation of self-assembling monolayers (SAM) with thiol-containing functional group. Thus, we conjugated Poly(ethylene glycol) 2-mercaptoethyl ether acetic acid (SH-PEG-COOH) with the chemical enhancer (Oleylamine, OAm) and the PEG molecules attach to the gold nanoparticles surface through a sulfur-gold atom bond. The surface modification were characterized by UV-visible spectrophotometry, transmission electron microscopy, zeta potential analysis, and fourier transform infrared spectroscopy.
Skin penetration of gold particles was observed by using confocal microscopy and transmission electron microscopy, the images show that rat skin revealed accumulation of gold nanoparticles in dermis of skin and the penetration amount of modification gold nanoparticles were higher than bare particles. As a result, the penetration of gold nanoparticle through skin can be enhanced by chemical penetration enhancement.

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