Dasari Srikanth, Singh Swati, Sivakumar Sri, Patra Ashis K
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
Department of Chemical Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
Chemistry. 2016 Nov 21;22(48):17387-17396. doi: 10.1002/chem.201603453. Epub 2016 Oct 24.
Dual-photosensitized stable Eu and Tb complexes, namely [Eu(dpq)(tfnb) ] (1) and [Tb(dpq)(tfnb) ] (2), in which dpq=dipyrido[3,2-d:2',3'-f]quinoxaline and Htfnb=4,4,4-trifluoro-1-(2-napthyl)-1,3-butanedione, were designed as bioimaging and light-responsive therapeutic agents. Their X-ray structures, photophysical properties, biological interactions, photoinduced DNA damage, photocytotoxicity, and cellular uptake properties were studied. Discrete mononuclear complexes adopt an eight-coordinated {LnN O } distorted square antiprism geometry with bidentate N,N-donor dpq and O,O-donor tfnb ligands. The designed probes have the advantage of dual-sensitizing antennae (dpq, Htfnb) to modulate their desirable optical properties for cellular imaging and light-responsive intracellular damage. The remarkable photostability, absence of inner-sphere water (q<1), and longer excited-state lifetimes of the complexes make them suitable as cellular-imaging probes. The dpq T state is well located energetically to allow efficient energy transfer (ET) to the emissive D and D states of Eu and Tb . This leads to higher quantum yields (φ=0.15-0.20) in aqueous media and makes these compounds suitable cellular-imaging probes. The complexes display significant binding ability toward DNA and bovine serum albumin (K≈10 m ). They effectively cleave supercoiled DNA to its nicked circular form at λ=365 nm through photoredox pathways. The cellular internalization studies showed cytosolic and nuclear localization. The remarkable photocytotoxicity of these probes offers a strategy towards developing photoresponsive Ln probes as cellular-imaging and phototherapeutic agents.
设计了双光敏稳定的铕（Eu）和铽（Tb）配合物，即[Eu(dpq)(tfnb) ]（1）和[Tb(dpq)(tfnb) ]（2），其中dpq = 二吡啶并[3,2 - d:2',3'- f]喹喔啉，Htfnb = 4,4,4 - 三氟 - 1 - (2 - 萘基)-1,3 - 丁二酮，作为生物成像和光响应治疗剂。研究了它们的X射线结构、光物理性质、生物相互作用、光诱导的DNA损伤、光细胞毒性和细胞摄取性质。离散单核配合物采用八配位的{LnN O }扭曲方形反棱柱几何结构，带有双齿N,N - 供体dpq和O,O - 供体tfnb配体。所设计的探针具有双敏化天线（dpq，Htfnb）的优势，可调节其理想的光学性质以用于细胞成像和光响应细胞内损伤。配合物显著的光稳定性、内球无水（q < 1）以及较长的激发态寿命使其适合作为细胞成像探针。dpq的T态在能量上位置合适，能够有效地将能量转移（ET）到Eu和Tb的发射性D和D态。这导致在水性介质中具有更高的量子产率（φ = 0.15 - 0.20），并使这些化合物适合作为细胞成像探针。这些配合物对DNA和牛血清白蛋白显示出显著的结合能力（K≈10 m）。它们通过光氧化还原途径在λ = 365 nm处有效地将超螺旋DNA切割成带切口的环状形式。细胞内化研究表明其定位于细胞质和细胞核。这些探针显著的光细胞毒性为开发光响应性Ln探针作为细胞成像和光治疗剂提供了一种策略。
