Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China.
Analyst. 2012 Dec 7;137(23):5565-70. doi: 10.1039/c2an35952a. Epub 2012 Oct 10.
It is a challenge to detect molecules lacking a chromophore, such as polyamines, by optical methods since they are insensitive to light. In order to detect the optical signals, it is compulsory to derive these molecules with optical labels, which, however, is complicated, time-consuming and may be expensive. In this work, a highly specific strategy for spermine detection is developed on the basis of the iodide-induced conformational change of polythiophene. By using the triplex complex of negatively charged double-stranded calf thymus DNA (ctDNA)-stabilized cationic polythiophene as a fluorescent probe, the highly specific detection of spermine could be realized since polythiophene, which will be released from the triplex complex owing to the condensation and aggregation of ctDNA with spermine, undergoes a conformational change from the random-coiled non-planar state to the highly conjugated planar form in the presence of iodide, resulting in a yellow-to-red color conversion and fluorescence quenching. The quenched fluorescence was found to be proportional to the spermine concentrations in the range of 1.2-50 μM with the limit of detection (LOD) being 0.5 μM (3σ/k).
通过光学方法检测缺乏生色团的分子（如多胺）是一项挑战，因为它们对光不敏感。为了检测光学信号，必须将这些分子衍生为光学标记，但这很复杂、耗时且可能昂贵。在这项工作中，基于聚噻吩的碘化物诱导构象变化，开发了一种用于检测亚精胺的高特异性策略。通过使用带负电荷的双链小牛胸腺 DNA（ctDNA）稳定的阳离子聚噻吩的三聚体复合物作为荧光探针，由于聚噻吩与亚精胺的 ctDNA 发生凝聚和聚集，从三聚体复合物中释放出来，在碘化物的存在下从无规卷曲的非平面状态到高度共轭的平面形式发生构象变化，导致颜色从黄色到红色的转变和荧光猝灭。发现猝灭的荧光与亚精胺浓度在 1.2-50 μM 范围内呈正比，检测限（LOD）为 0.5 μM（3σ/k）。
