Department of Materials Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo, 125-8585, Japan.
Anal Sci. 2021 Mar 10;37(3):485-489. doi: 10.2116/analsci.20SCP09. Epub 2020 Dec 18.
Fluorescence imaging using the over-thousand-nanometer (OTN) near-infrared (NIR) light is an emerging method for an in vivo imaging analysis of deep tissues without physical sectioning. Polymer micelle nanoparticles (PNPs) composed of organic polymers encapsulating an OTN-NIR fluorescent dye, IR-1061, in their hydrophobic core are expected to be biocompatible probes. Because IR-1061 quickly quenches due to the vibration of polar hydroxyl bonding in its surroundings, the influence of hydroxyl ions should be minimized. Herein, we investigated the effect of the hydrogen ion concentration during the preparation process using IR-1061 and an organic polymer, poly(ethylene glycol)-block-polystyrene (PEG-b-PSt), on the emission properties of the obtained OTN-PNPs. The OTN-PNP has a hydrodynamic diameter of 20 - 30 nm and emits 1110-nm fluorescence that is applicable to angiography. The loading efficiency of IR-1061 in the OTN-PNPs increased when prepared in an aqueous solution with a low hydroxyl ion concentration. In this solution (pH 3.0), highly emissive OTN-PNPs was obtained with IR-1061 at lower nominal concentrations. Decreasing the hydroxyl ion concentration during the preparation process yields highly emissive OTN-PNPs, which may improve the in vivo imaging analysis of biological phenomena in deep tissues.
使用千纳米以上（OTN）近红外（NIR）光的荧光成像是一种新兴的方法，可用于对未经物理切片的深层组织进行体内成像分析。由有机聚合物包裹 OTN-NIR 荧光染料 IR-1061 的聚合物胶束纳米粒子（PNP）有望成为生物相容性探针。由于 IR-1061 周围的极性羟基键的振动会迅速猝灭，因此应尽量减少羟基离子的影响。在此，我们研究了在制备过程中使用 IR-1061 和有机聚合物聚（乙二醇）-嵌段-聚苯乙烯（PEG-b-PSt）时氢离子浓度对所得 OTN-PNP 发射特性的影响。OTN-PNP 的水动力学直径为 20-30nm，发射 1110nm 的荧光，适用于血管造影。当在低羟基离子浓度的水溶液中制备时，OTN-PNP 中 IR-1061 的负载效率增加。在该溶液（pH3.0）中，以较低的名义浓度获得了具有高发光性的 OTN-PNP。在制备过程中降低羟基离子浓度可得到高发光性的 OTN-PNP，这可能会改善深层组织中生物现象的体内成像分析。
