Center for Biosignatures Discovery Automation, Biodesign Institute, Arizona State University , Tempe, Arizona 85287, United States.
School for Biological and Health Systems Engineering, Arizona State University , Tempe, Arizona 85281, United States.
ACS Appl Mater Interfaces. 2018 Jan 17;10(2):1556-1565. doi: 10.1021/acsami.7b15796. Epub 2018 Jan 5.
In this paper, we report synthesis and characterization of a novel multimodality (MRI/fluorescence) probe for pH sensing and imaging. A multifunctional polymer was derived from poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) and integrated with a naphthalimide-based-ratiometric fluorescence probe and a gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex (Gd-DOTA complex). The polymer was characterized using UV-vis absorption spectrophotometry, fluorescence spectrofluorophotometry, magnetic resonance imaging (MRI), and confocal microscopy for optical and MRI-based pH sensing and cellular imaging. In vitro labeling of macrophage J774 and esophageal CP-A cell lines shows the polymer's ability to be internalized in the cells. The transverse relaxation time (T) of the polymer was observed to be pH-dependent, whereas the spin-lattice relaxation time (T) was not. The pH probe in the polymer shows a strong fluorescence-based ratiometric pH response with emission window changes, exhibiting blue emission under acidic conditions and green emission under basic conditions, respectively. This study provides new materials with multimodalities for pH sensing and imaging.
在本文中，我们报告了一种新型多模态（MRI/荧光）探针用于 pH 传感和成像的合成与表征。一种多功能聚合物是由聚（N-（2-羟丙基）甲基丙烯酰胺）（PHPMA）衍生而来，并与基于萘酰亚胺的比率荧光探针和钆-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸络合物（Gd-DOTA 络合物）集成在一起。使用紫外-可见吸收分光光度法、荧光分光光度法、磁共振成像（MRI）和共聚焦显微镜对聚合物进行了表征，用于光学和基于 MRI 的 pH 传感和细胞成像。体外标记巨噬细胞 J774 和食管 CP-A 细胞系表明聚合物具有在细胞内内化的能力。聚合物的横向弛豫时间（T）被观察到是 pH 依赖性的，而自旋-晶格弛豫时间（T）则不是。聚合物中的 pH 探针显示出基于荧光的强比率 pH 响应，具有发射窗口变化，分别在酸性条件下显示蓝色发射，在碱性条件下显示绿色发射。这项研究为 pH 传感和成像提供了具有多模态的新材料。
