结合了氮杂蒽酮敏化剂的四个不同手性配体的一系列Eu和Tb配合物已被评估为碳酸氢根阴离子的探针。在环境pH下,用碳酸氢盐,乳酸盐,柠檬酸盐,磷酸盐和血清白蛋白评估它们的结合亲和力。通过调节圆偏振发光来发出结合信号,并且通过检查发射强度比的变化来测量表观亲和常数。竞争实验表明,在这些物种和ATP处于正常生理值的情况下,可以在10至35 m M的浓度范围内选择性测定碳酸氢根。通过使用常见配体的Eu和Tb配合物的混合物检查红色/绿色发射光的比率,还可以报告碳酸氢盐的水平。这些方法已适用于测定人血清中的碳酸氢根,并用于通过共聚焦显微镜评估几种不同细胞类型中线粒体中碳酸氢根的水平。
Effect of Lanthanide Complex Structure on Cell Viability and Association
摘要:
A systematic study of the effect of hydrophobicity and charge on the cell viability and cell association of lanthanide metal complexes is presented. The terbium luminescent probes feature a macrocyclic polyaminocarboxylate ligand (DOTA) in which the hydrophobicity of the antenna and that of the carboxyamide pendant arms are independently varied. Three sensitizing antennas were investigated in terms of their function in vitro: 2-methoxy-isophthalamide (IAM(OMe)), 2-hydroxyisophthalamide (IAM), and 6-methylphenanthridine (Phen). Of these complexes, Tb-DOTA-IAM exhibited the highest quantum yield, although the higher cell viability and more facile synthesis of the structurally related Tb-DOTA-IAM(OMe) platform renders it more attractive. Further modification of this latter core structure with carboxyamide arms featuring hydrophobic benzyl, hexyl, and trifluoro groups as well as hydrophilic amino acid based moieties generated a family of complexes that exhibit high cell viability (ED50 > 300 mu M) regardless of the lipophilicity or the overall complex charge. Only the hexyl-substituted complex reduced cell viability to 60% in the presence of 100 mu M complex. Additionally, cellular association was investigated by ICP-MS and fluorescence microscopy. Surprisingly, the hydrophobic moieties did not increase cell association in comparison to the hydrophilic amino acid derivatives. It is thus postulated that the hydrophilic nature of the 2-methoxyisophthalamide antenna (IAM(OMe)) disfavors the cellular association of these complexes. As such, responsive luminescent probes based on this scaffold would be appropriate for the detection of extracellular species.