Fluorine End-Capped Optical Fibers for Photosensitizer Release and Singlet Oxygen Production
Fluorine End-Capped Optical Fibers for Photosensitizer Release and Singlet Oxygen Production
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DOI：
10.1021/jo3006107
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发表时间：
2012-05-18
影响因子：
3.6
通讯作者：
Greer, Alexander
中科院分区：
文献类型：
--
作者：
Bartusik, Dorota;Aebisher, David;Greer, Alexander
纤维光学技术用于产生单线态氧和释放脱镁叶绿酸光敏剂的有用性已经通过多孔Vycor玻璃尖端的抛光而增加。单线态氧通过光纤尖端与669 nm光和氧一起出现，在单线态氧与乙烯间隔基[2 + 2]加成和二氧杂环丁烷中间体断裂后释放敏化剂分子。从非氟化玻璃头切换到氟化玻璃头导致离开敏化剂的吸附亲和力明显降低，并改善了向均匀甲苯溶液和牛组织中的释放，但在水中没有发现差异，因为敏化剂是不溶性的。高的表面覆盖度的nonperoxorohexylsilane提高裂解效率的15%，在乙烯网站。氟硅烷基团还引起拥挤，并且似乎减少了O-1（2）进入乙烯位点，这减弱了总猝灭速率常数k（T），尽管在氟硅烷涂覆的二氧化硅处比天然SiOH二氧化硅处浪费的O-1（2）（来自表面物理猝灭）更少。观察结果支持了一种猝灭机制，即SiOH基团取代氟硅烷C-H和C-F基团提高了纤维尖端界面处的O-1（2）寿命，这是由于电子-振动能量转移效率较低。
The usefulness of a fiber optic technique for generating singlet oxygen and releasing the pheophorbide photosensitizer has been increased by the fluorination of the porous Vycor glass tip. Singlet oxygen emerges through the fiber tip with 669-nm light and oxygen, releasing the sensitizer molecules upon a [2 + 2] addition of singlet oxygen with the ethene spacer and scission of a dioxetane intermediate. Switching from a nonfluorinated to a fluorinated glass tip led to a clear reduction of the adsorbtive affinity of the departing sensitizer with improved release into homogeneous toluene solution and bovine tissue, but no difference was found in water since the sensitizer was insoluble. High surface coverage of the nonafluorohexylsilane enhanced the cleavage efficiency by 15% at the ethene site. The fluorosilane groups also caused crowding and seemed to reduce access of O-1(2) to the ethene site, which attenuated the total quenching rate constant k(T), although there was less wasted O-1(2) (from surface physical quenching) at the fluorosilane-coated than the native SiOH silica. The observations support a quenching mechanism that the replacement of the SiOH groups for the fluorosilane C-H and C-F groups enhanced the O-1(2) lifetime at the fiber tip interface due to less efficient electronic-to-vibronic energy transfer.