Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, NY, 11790, USA.
Angew Chem Int Ed Engl. 2018 Nov 19;57(47):15496-15499. doi: 10.1002/anie.201809783. Epub 2018 Oct 26.
Lanthanide luminescence, while ideal for in vivo applications owing to sharp emission bands within the optical window, requires high-intensity, short-wavelength excitation of small organic "antenna" chromophores in the vicinity of the lanthanide complex to access excited f-orbital states through intersystem crossing. Herein, we explored Cherenkov radiation of the radioisotopes F and Zr as an in situ source of antenna excitation. The effective inter- and intramolecular excitation of the terbium(III) complexes of a macrocylic polyaminocarboxylate ligand (hydration number (q)=0, quantum yield (φ)=47 %) as well as its analogue functionalized to append an intramolecular Cherenkov excitation source (q=0.07, φ=63 %) was achieved. Using conventional small-animal fluorescence imaging equipment, we have determined a detection limit of 2.5 nmol of Tb(III) complex in presence of 10 μCi of F or Zr. Our system is the first demonstration of the optical imaging of discrete luminescent lanthanide complexes without external short-wave excitation.
镧系元素的发光虽然由于在光学窗口内具有尖锐的发射带而非常适合体内应用，但需要高强度、短波长的近邻镧系配合物的小有机“天线”发色团的激发，才能通过系间穿越进入激发的 f 轨道态。在此，我们探讨了放射性同位素 F 和 Zr 的切伦科夫辐射作为天线激发的原位源。螯合大环多胺羧酸配体的铽(III)配合物的有效分子间和分子内激发（水合数(q)=0，量子产率(φ)=47%）以及其类似物的功能化以附加分子内切伦科夫激发源（q=0.07，φ=63%）得以实现。使用常规的小动物荧光成像设备，我们在存在 10 μCi 的 F 或 Zr 的情况下确定了 Tb(III)配合物的检测限为 2.5 nmol。我们的系统是第一个无需外部短波激发即可对离散发光镧系元素配合物进行光学成像的演示。
