金奈米粒子在雷射去除白色毛髮上的應用
Abstract
雷射除毛是利用「選擇性光熱療法」的特性，因深入皮膚的雷射光能量被毛幹、毛囊中的黑色素細胞吸收，以逹到破壞毛囊萎縮毛根的目的來除毛。但白色毛髮因為缺少有效的吸光物質，不像黑色毛髮般具有足夠的黑色素來吸收雷射能量，因此難以利用雷射逹到永久除毛的效果。本篇文章利用金奈米粒子當作白色毛髮的吸光團，透過滲透的方式，利用硫金鍵將金奈米粒子附著在毛髮上並滲透入毛囊。由於金奈米粒子的吸收位於520 nm，所以我們使用放射波長為532 nm 的釹雅各雷射，將能量傳逹至金奈米粒子上，進而破壞毛囊。
由我們的實驗結果發現金奈米粒子可以牢固地附著在毛髮上，並且附著的時間約6小時即可，且藉由除毛膏的預處理可以使金奈米粒子滲透入毛囊超過80 μm 的深度，如此一來將可以使雷射光的能量由金奈米粒子傳至更深的毛囊處，逹到破壞毛囊的效果。應用於活體實驗部份，滲透入金奈米粒子的皮膚在雷射過後，在一個月的觀察之下，發現毛髮生長的速度比對照組較慢。而且我們也發現使用
3 J/cm2的雷射能量具有最少的副作用，使用5 J/cm2的雷射能量除毛效果則最好。但由於金奈米粒子只利於利用低波長的能量，因些對於除毛效果並不顯著，未來將研究使用能吸收長波長能量的奈米粒子來達到永久除毛的效果。
The technology employed for hair removal by lasers/light-based systems is based on the principle of selective photothermolysis. In order to damage hair follicles, laser light must be absorbed by the chromophore melamin within the hair shaft and follicle. Unlike dark hair, white hair is lack of the chromophore melamin and hard to be destroyed by absorbing laser light. Our study was using gold nanoparticles as a chromophore to absorb the laser light and transfer the heat to the hair follicle. Because of the absorption wavelength at 520 nm of gold nanoparticles, we chose the 532 nm Nd:YAG laser to process the laser epilation of white hair mouse on this experiment. In our study, gold nanoparticles could be firmly adsorbed on the hair surface and only needed 6 hours. If pretreated with hair removal cream on the mouse skin, the gold nanoparticles can penetrated into hair follicle in the depth of 80 μm. After the experiment on the white mouse, we found that the regrowth rate of the mouse hair was slower if we use gold nanoparticles as the chromophore penetrated into hair follicle, and the use of laser fluence of 3 J/cm2 has the minimum side effects, 5 J/cm2 has the greatest epilation result. In future we will try other nanoparticles those can absorb the energy of long wavelength lasers to attain to white hair epilation.
The technology employed for hair removal by lasers/light-based systems is based on the principle of selective photothermolysis. In order to damage hair follicles, laser light must be absorbed by the chromophore melamin within the hair shaft and follicle. Unlike dark hair, white hair is lack of the chromophore melamin and hard to be destroyed by absorbing laser light. Our study was using gold nanoparticles as a chromophore to absorb the laser light and transfer the heat to the hair follicle. Because of the absorption wavelength at 520 nm of gold nanoparticles, we chose the 532 nm Nd:YAG laser to process the laser epilation of white hair mouse on this experiment. In our study, gold nanoparticles could be firmly adsorbed on the hair surface and only needed 6 hours. If pretreated with hair removal cream on the mouse skin, the gold nanoparticles can penetrated into hair follicle in the depth of 80 μm. After the experiment on the white mouse, we found that the regrowth rate of the mouse hair was slower if we use gold nanoparticles as the chromophore penetrated into hair follicle, and the use of laser fluence of 3 J/cm2 has the minimum side effects, 5 J/cm2 has the greatest epilation result. In future we will try other nanoparticles those can absorb the energy of long wavelength lasers to attain to white hair epilation.
Description
Keywords
金奈米粒子, 雷射除毛, 毛髮, 雙光子