Fluorescence-quenching of a liposomal-encapsulated near-infrared fluorophore as a tool for in vivo optical imaging.
Fluorescence-quenching of a liposomal-encapsulated near-infrared fluorophore as a tool for in vivo optical imaging.
复制标题
DOI：
10.3791/52136
复制
发表时间：
2015-01
期刊：
影响因子：
--
通讯作者：
F. Tansi;R. Rüger;Markus Rabenhold;F. Steiniger;A. Fahr;I. Hilger
中科院分区：
文献类型：
--
作者：
F. Tansi;R. Rüger;Markus Rabenhold;F. Steiniger;A. Fahr;I. Hilger
光学成像提供了广泛的诊断模式，并作为生物医学成像的工具吸引了很多兴趣。尽管目前有大量的成像技术和仪器的进步，仍然需要高灵敏度的探针，适用于体内成像。可用的临床前荧光探针的一个典型问题是它们在体内的快速清除，这降低了它们的成像灵敏度。为了避免快速清除，增加靶位点的染料分子数量，从而减少背景自发荧光，将近红外荧光染料DY-676-COOH包封在脂质体中，并验证其用于炎症体内成像的潜力。DY-676以其在高浓度下自淬灭的能力而闻名。我们首先确定了适合于自猝灭的浓度，然后将该猝灭浓度包封到PEG化脂质体的水性内部。为了证实脂质体的淬灭和活化潜力，我们使用了导致脂质体膜损坏而不影响包封染料的苛刻冷冻方法。以高水平荧光猝灭为特征的脂质体被称为Lip-Q。我们通过不同细胞系的实验表明，Lip-Q的摄取主要是通过吞噬作用，这反过来又能够表征其作为小鼠模型中炎症体内成像工具的潜力。此外，我们使用酵母多糖诱导的小鼠水肿模型来证实Lip-Q在体内炎症光学成像中的潜力。考虑到由于炎症诱导的增强的渗透性和保留（EPR）效应而可能的摄取，在动物试验中将具有低的非淬灭浓度的DY-676-COOH（称为Lip-dQ）和游离DY-676-COOH的始终在用脂质体制剂与Lip-Q进行比较。
Optical imaging offers a wide range of diagnostic modalities and has attracted a lot of interest as a tool for biomedical imaging. Despite the enormous number of imaging techniques currently available and the progress in instrumentation, there is still a need for highly sensitive probes that are suitable for in vivo imaging. One typical problem of available preclinical fluorescent probes is their rapid clearance in vivo, which reduces their imaging sensitivity. To circumvent rapid clearance, increase number of dye molecules at the target site, and thereby reduce background autofluorescence, encapsulation of the near-infrared fluorescent dye, DY-676-COOH in liposomes and verification of its potential for in vivo imaging of inflammation was done. DY-676 is known for its ability to self-quench at high concentrations. We first determined the concentration suitable for self-quenching, and then encapsulated this quenching concentration into the aqueous interior of PEGylated liposomes. To substantiate the quenching and activation potential of the liposomes we use a harsh freezing method which leads to damage of liposomal membranes without affecting the encapsulated dye. The liposomes characterized by a high level of fluorescence quenching were termed Lip-Q. We show by experiments with different cell lines that uptake of Lip-Q is predominantly by phagocytosis which in turn enabled the characterization of its potential as a tool for in vivo imaging of inflammation in mice models. Furthermore, we use a zymosan-induced edema model in mice to substantiate the potential of Lip-Q in optical imaging of inflammation in vivo. Considering possible uptake due to inflammation-induced enhanced permeability and retention (EPR) effect, an always-on liposome formulation with low, non-quenched concentration of DY-676-COOH (termed Lip-dQ) and the free DY-676-COOH were compared with Lip-Q in animal trials.