Stephenson Mat, Reichardt Christian, Pinto Mitch, Wächtler Maria, Sainuddin Tariq, Shi Ge, Yin Huimin, Monro Susan, Sampson Eric, Dietzek Benjamin, McFarland Sherri A
Department of Chemistry, Acadia University , Wolfville, NS B4P 2R6, Canada.
J Phys Chem A. 2014 Nov 13;118(45):10507-21. doi: 10.1021/jp504330s. Epub 2014 Jul 1.
Combining the best attributes of organic photosensitizers with those of coordination complexes is an elegant way to achieve prolonged excited state lifetimes in Ru(II) dyads. Not only do their reduced radiative and nonradiative rates provide ample time for photosensitization of reactive oxygen species at low oxygen tension but they also harness the unique properties of (3)IL states that can act as discrete units or in concert with (3)MLCT states. The imidazo[4,5-f][1,10]phenanthroline framework provides a convenient tether for linking π-expansive ligands such as pyrene to a Ru(II) scaffold, and the stabilizing coligands can fine-tune the chemical and biological properties of these bichromophoric systems. The resulting dyads described in this study exhibited nanomolar light cytotoxicities against cancer cells with photocytotoxicity indices exceeding 400 for some coligands employed. This potency extended to bacteria, where concentrations as low as 10 nM destroyed 75% of a bacterial population. Notably, these dyads remained extremely active against biofilm with light photocytotoxicities against these more resistant bacterial populations in the 10-100 nM regime. The results from this study demonstrate the versatility of these highly potent photosensitizers in destroying both cancer and bacterial cells and expand the scope of compounds that utilize low-lying (3)IL states for photobiological applications.
将有机光敏剂的最佳特性与配位络合物的特性相结合，是在钌（II）二元体系中实现延长激发态寿命的一种巧妙方法。它们降低的辐射和非辐射速率不仅为在低氧张力下光敏化活性氧提供了充足的时间，而且还利用了三重态激发态（3）IL的独特性质，这些性质可以作为离散单元或与三重态金属-配体电荷转移态（3）MLCT协同作用。咪唑并[4,5-f][1,10]菲咯啉骨架为将芘等π-扩展配体连接到钌（II）支架上提供了便利的连接基团，而稳定的共配体可以微调这些双发色体系的化学和生物学性质。本研究中描述的所得二元体系对癌细胞表现出纳摩尔级的光细胞毒性，对于所使用的一些共配体，光细胞毒性指数超过400。这种效力扩展到细菌，低至10 nM的浓度就能破坏75%的细菌群体。值得注意的是，这些二元体系对生物膜仍然极具活性，在10 - 100 nM范围内对这些更具抗性的细菌群体具有光细胞毒性。这项研究的结果证明了这些高效光敏剂在破坏癌细胞和细菌细胞方面的多功能性，并扩大了利用低能三重态激发态（3）IL进行光生物学应用的化合物范围。
