目前面臨的挑戰包括進行較深層組織治療時，用來治療所使用的激發光源穿透深度是一大考驗，若使用紫外/可見光波長範圍的光源，可能會在組織體內產生散射導致光穿透深度較淺。因此我們想要開發第三生物視窗作為激發光源，在此波長能夠有較好的組織穿透深度並且能減少組織體內的光散射，是深層組織治療的理想選擇，因此利用摻雜鉺離子的上轉換奈米粒子作為吸收第三生物視窗的光。
首先我們合成核－殼－殼上轉換奈米粒子(NaYF4:Er@NaYF4@NaYF4)，可以看到覆蓋惰性殼層後，能夠有效避免活化劑 (Er3+) 擴散至外界環境導致螢光焠滅。接著我們使用逆微胞法將富勒烯和上轉換奈米粒子同時包覆在二氧化矽殼層中，當上轉換奈米粒子照射1550nm雷射後，會放出540nm綠光放光，然而富勒烯在波長532nm單態氧轉換效率很高，因此我們希望上轉換奈米粒子放出的綠光能夠藉由頻率共振能量轉移的方式來活化富勒烯，使其能夠有效產生單態氧以進行光動力治療。

The present challenges included penetration depth of activating light as external trigger for smart nanodrugs for deeper tissue treatment. Ideally, NIR-III biological window (1550-1870 nm) had advantage of deeper tissue theragnostic considering the extended penetration depth and reducing light scattering. We provided NIR-III responsive Er3+ doped upconversion nanoparticles.
First, we synthesized upconversion nanoparticles (NaYF4:Er@NaYF4@NaYF4). After coating the inert shell, it could protect the activator (Er3+) diffusing to outer surroundings. Thus, it could obviously enhance the intensity of fluorescence. We used reverse micelle sol-gel method to combined with upconversion nanoparticles and fullerene inside the silica shell simultaneously. We chose 1550 nm laser as the light source. Once irradiating the upconversion nanoparticles, it would generate emission at 540 nm. Fullerene had great singlet oxygen conversion efficiency at 532 nm. Thus, it could be activated by frequency resonance energy transfer (FRET) and generate efficient singlet oxygen for photodynamic therapy.

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