Maarek J M, Holschneider D P, Harimoto J
Department of Biomedical Engineering, University of Southern California, OHE 500, University Park, Los Angeles, CA 90089-1451, USA.
J Photochem Photobiol B. 2001 Dec 31;65(2-3):157-64. doi: 10.1016/s1011-1344(01)00264-0.
Indocyanine green (ICG) has been widely used in cardiovascular, hepatic, and ophthalmologic studies. Application of this fluorescent dye has been handicapped by its poor stability in solution and by the complex dependence of its fluorescence intensity on concentration. Noncovalent interactions between ICG and sodium polyaspartate (PASP) stabilize ICG fluorescence in aqueous solution, but the effect of PASP on ICG fluorescence in blood has not been described. The current study had two main goals: first, to characterize in vitro in blood the relationship between fluorescence intensity and concentration of ICG-PASP (ICG) and the stability of this relationship over time; second, to test a new phenomenological model describing the dependence of ICG fluorescence on concentration. Freshly-prepared ICG and ICG-PASP solutions produced the same fluorescence intensity over a wide range of concentrations (0.0005-0.1271 mg/ml). The peak fluorescence of ICG was reduced by 11% after 10 h and by 72% at 7 days. In contrast, the peak fluorescence intensity of ICG-PASP solutions was nearly unchanged for up to 14 days. The dependence of the fluorescence intensity on concentration was accurately represented by our model that accounted for the generation of fluorescence following light absorption, and for the reabsorption of the emitted fluorescence by ICG.
吲哚菁绿（ICG）已广泛应用于心血管、肝脏和眼科研究。这种荧光染料的应用受到其在溶液中稳定性差以及荧光强度对浓度复杂依赖性的限制。ICG与聚天冬氨酸钠（PASP）之间的非共价相互作用可稳定ICG在水溶液中的荧光，但尚未描述PASP对血液中ICG荧光的影响。本研究有两个主要目标：第一，在体外血液中表征ICG-PASP（ICG）荧光强度与浓度之间的关系以及这种关系随时间的稳定性；第二，测试一种描述ICG荧光对浓度依赖性的新现象学模型。新鲜制备的ICG和ICG-PASP溶液在很宽的浓度范围（0.0005-0.1271 mg/ml）内产生相同的荧光强度。ICG的峰值荧光在10小时后降低了11%，在7天时降低了72%。相比之下，ICG-PASP溶液的峰值荧光强度在长达14天内几乎没有变化。我们的模型准确地描述了荧光强度对浓度的依赖性，该模型考虑了光吸收后荧光的产生以及ICG对发射荧光的重吸收。
