上轉換BaGdF5:Yb3+, Er3+螢光粉之合成特性鑑定與其在生化檢測與染料敏化太陽能電池之應用

Abstract

上轉換螢光體相較於量子點，具較低生物毒性、光穩定性良好，且可利用近紅外光源加以激發，並能穿透組織深層等優勢，故其在生醫應用之發展備受矚目。本研究利用水熱法製備上轉換奈米級BaGdF5:Yb3+, Er3+螢光體，利用親水性聚乙二醇(PEG)作為分散劑，藉由pH值及EDTA等參數作調控，得到分散性良好、晶粒尺寸約為28 nm之PEG-capped BaGdF5:Yb3+, Er3+上轉換奈米粒子，其表面經SiO2之包覆與胺基之修飾，有利於其在生物上之應用。 本研究藉由胺基修飾之上轉換BaGdF5:Yb3+, Er3+＠PEG@SiO2螢光體放光特性與奈米粒子表面特性之研究來篩選可有效抑制玻尿酸水解酶之抑制劑，研究結果顯示，以抗壞血酸作為抑制劑在濃度＜50 mM具有最佳之抑制效果，然其羥基在抗壞血酸濃度＞50 mM將造成奈米粒子聚集，抑制效果較有限。另一方面，本研究亦利用上轉換BaGdF5:18% Yb3+, 1% Er3+@PEG與BaGdF5:18% Yb3+, 1% Er3+ @PEG＠SiO2螢光粉塗佈於染敏太陽能電池鉑電極背層，該電池之轉換效率因而分別提高了9.94 %與7.01 %；當以980 nm波長光源激發，可使Jsc分別提升了17%、5.8%，證實上轉換螢光粉在染敏太陽能電池上具應用的潛力。

Compared with conventional fluorophores that show many limitations, lanthanide-doped upconversion nanoparticles (UCNPs) exhibit superiority such as low cytotoxicity, deep tissue penetration upon NIR excitation, photostability and good biocompatibility. Accordingly, the development of UCNPs in biomedical field has become the center of attention. We have synthesized upconversion BaGdF5:Yb3+, Er3+ nanophosphors by hydrothermal method. By the addition of dispersing agent polyethylene glycol (PEG) and the controlling of experiment parameters (pH, EDTA amount), PEG-capped BaGdF5:Yb3+, Er3+ upconversion nanoparticles with average size of 28 nm and good dispersibility were obtained. Then the surface of UCNPs was coated with inorganic silica layer and modified with amine functional group, which is beneficial for its bio-application. The practical effect of hyaluronidases (HAases) in cancer therapy has been proven in many studies. Hence, discussing further about the interaction between hyaluronidases and physiology, developing specific inhibitors or inhibitors that suppress the activity of HAases are of great significance for cancer therapy. In this study, we choose inhibitors restraining HAases effectively by the optical and surface properties of amine-functionalized BaGdF5:Yb3+,Er3＠PEG@SiO2 UCNPs. The results show the good performance as we use ascorbic acid as an inhibitor at the concentration of 50 mM. On the other hand, we coated BaGdF5:18% Yb3+, 1% Er3+@PEG and BaGdF5:18% Yb3+, 1% Er3+@PEG@SiO2 on the backside of DSSCs (AM1.5G), which resulted in the raising efficiency of about 9.94% and 7.01%, respectively. Upon excitation of DSSCs by using 980 nm fiber laser, the Jsc of DSSCs increase 17% and 5.8% , respectively. In this work, we have demonstrated the potential applications of UCNPs in the development of enzyme system and DSSCs.