Department of Chemistry & Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN, 46545, USA.
Chemistry. 2021 Oct 19;27(58):14535-14542. doi: 10.1002/chem.202102816. Epub 2021 Sep 24.
Indocyanine Green (ICG) is a clinically approved near-infrared fluorescent dye that is used extensively for various imaging and diagnostic procedures. One drawback with ICG is its instability in water, which means that reconstituted clinical doses have to be used very shortly after preparation. Two deuterated versions of ICG were prepared with deuterium atoms on the heptamethine chain, and the spectral, physiochemical, and photostability properties were quantified. A notable mechanistic finding is that self-aggregation of ICG in water strongly favors dye degradation by a photochemical oxidative dimerization reaction that gives a nonfluorescent product. Storage stability studies showed that replacement of C-H with C-D decreased the dimerization rate constant by a factor of 3.1, and it is likely that many medical and preclinical procedures will benefit from the longer shelf-lives of these two deuterated ICG dyes. The discovery that ICG self-aggregation promotes photoinduced electron transfer can be exploited as a new paradigm for next-generation photodynamic therapies.
吲哚菁绿（ICG）是一种临床批准的近红外荧光染料，广泛用于各种成像和诊断程序。ICG 的一个缺点是其在水中的不稳定性，这意味着配制后的临床剂量必须在很短的时间内使用。用氘原子取代吲哚菁绿的七甲川链上的两个氘代版本，并对其光谱、物理化学和光稳定性特性进行了定量分析。一个值得注意的机制发现是，ICG 在水中的自聚集强烈有利于通过光化学氧化二聚化反应使染料降解，该反应产生非荧光产物。储存稳定性研究表明，用 C-D 取代 C-H 将二聚化速率常数降低了 3.1 倍，这两种氘代 ICG 染料的保质期更长，许多医学和临床前的程序将从中受益。ICG 自聚集促进光诱导电子转移的发现，可以作为下一代光动力疗法的新范例加以利用。
