The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, China.
Analyst. 2011 Jun 21;136(12):2464-70. doi: 10.1039/c0an00914h. Epub 2011 May 10.
We developed a novel spin-labeled terbium complex Tb(3+)/cs124-DTPA-TEMPO (1) by covalently labeling a nitroxide radical on the terbium complex for monitoring free radicals of various areas. This lanthanide complex probe shows a high EPR signal which resulted from the nitroxide radical moiety, and is weakly luminescent which resulted from the intramolecular quenching effect of the nitroxide radical on sensitised terbium luminescence. The intensity of both the EPR and luminescence can be modulated by eliminating the paramagnetism of the nitroxide radical through recognition of a carbon-centered radical analyte and thus gives a quantification of the analyte. We have preliminarily applied this probe in the luminescent detection of model carbon-centered radicals and hydroxyl radicals (·OH). This probe is water-soluble and contains lanthanide-luminescence properties, favorable for the time-resolved luminescence technique. The investigation of the intramolecular quenching process has showed that the labeled nitroxide radical quenches multiple excited states of the terbium complex, resulting in highly efficient quenching of terbium luminescence. This probe is the first example of intramolecular modulation of lanthanide luminescence by a nitroxide radical.
我们通过将氮氧自由基共价标记在铽配合物上来开发一种新型的自旋标记铽配合物 Tb(3+)/cs124-DTPA-TEMPO（1），用于监测各个领域的自由基。这种镧系元素配合物探针具有来自氮氧自由基部分的高 EPR 信号，并且由于氮氧自由基对敏化铽发光的分子内猝灭效应而具有弱发光性。EPR 和发光的强度都可以通过通过识别碳中心自由基分析物来消除氮氧自由基的顺磁性来调节，从而对分析物进行定量。我们已经初步将这种探针应用于模型碳中心自由基和羟基自由基（·OH）的发光检测。这种探针水溶性好，含有镧系元素发光性质，有利于时间分辨发光技术。对分子内猝灭过程的研究表明，标记的氮氧自由基猝灭了铽配合物的多个激发态，导致铽发光的高效猝灭。该探针是首例通过氮氧自由基对镧系元素发光进行分子内调制的实例。
