Gong An, Ma Xuehua, Xiang Lingchao, Ren Wenzhi, Shen Zheyu, Wu Aiguo
Key Laboratory of Magnetic Materials and Devices, Chinese Academy of Sciences, & Division of Functional Materials and Nano Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China.
Key Laboratory of Magnetic Materials and Devices, Chinese Academy of Sciences, & Division of Functional Materials and Nano Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China.
Colloids Surf B Biointerfaces. 2014 Apr 1;116:561-7. doi: 10.1016/j.colsurfb.2014.01.038. Epub 2014 Feb 1.
The aim of this study is to explore an improved double emulsion technology with in situ reaction of lysine (Lys) and glutaraldehyde (GA) for fabricating autofluorescent Lys-poly(lactic-co-glycolic acid)-GA (Lys-PLGA-GA) microcapsules as novel ultrasonic/fluorescent dual-modality contrast agents. Scanning electron microscope (SEM) and static light scattering (SLS) results show that 80% of the Lys-PLGA-GA microcapsules are larger than 1.0 μm and 90% of them are smaller than 8.9 μm. SEM and laser confocal scanning microscope (LCSM) data demonstrate that the structure of our Lys-PLGA-GA microcapsules is hollow. Compared with the FT-IR spectrum of PLGA microcapsules, a new peak at 1,644 cm(-1) in that of Lys-PLGA-GA microcapsules confirms the formed Schiff base in Lys-PLGA-GA microcapsules. LCSM images and fluorescence spectra show that our Lys-PLGA-GA microcapsules exhibit bright and stable autofluorescence without conjugation to any fluorescent agent, which can be ascribed to the n-π transitions of the CN bonds in the formed Schiff base. Our autofluorescent Lys-PLGA-GA microcapsules might have more wide applications than traditional fluorescent dyes because their excitation and emission spectra are both broad. The fluorescence intensity can also be tuned by the feeding amount of Lys and GA. The MTT assays reveal that the autofluorescent microcapsules are biocompatible. The results of fluorescent imaging in cells and in vitro ultrasonic imaging demonstrate the feasibility of our autofluorescent Lys-PLGA-GA microcapsules as ultrasonic/fluorescent dual-modality contrast agents. This novel ultrasonic/fluorescent dual-modality contrast agent might have potential for a variety of biological and medical applications.
本研究的目的是探索一种改进的双乳液技术，该技术利用赖氨酸（Lys）和戊二醛（GA）的原位反应来制备自发荧光的赖氨酸-聚乳酸-乙醇酸共聚物-GA（Lys-PLGA-GA）微胶囊，作为新型超声/荧光双模态造影剂。扫描电子显微镜（SEM）和静态光散射（SLS）结果表明，80%的Lys-PLGA-GA微胶囊直径大于1.0μm，90%的微胶囊直径小于8.9μm。SEM和激光共聚焦扫描显微镜（LCSM）数据表明，我们制备的Lys-PLGA-GA微胶囊结构为中空。与PLGA微胶囊的傅里叶变换红外光谱（FT-IR）相比，Lys-PLGA-GA微胶囊的FT-IR光谱在1644 cm-1处出现一个新峰，证实了Lys-PLGA-GA微胶囊中形成了席夫碱。LCSM图像和荧光光谱表明，我们制备的Lys-PLGA-GA微胶囊在未与任何荧光剂偶联的情况下表现出明亮且稳定的自发荧光，这可归因于形成的席夫碱中-CN键的n-π跃迁。我们的自发荧光Lys-PLGA-GA微胶囊可能比传统荧光染料具有更广泛的应用，因为它们的激发光谱和发射光谱都很宽。荧光强度也可以通过Lys和GA的进料量进行调节。MTT分析表明，自发荧光微胶囊具有生物相容性。细胞内荧光成像和体外超声成像结果证明了我们制备的自发荧光Lys-PLGA-GA微胶囊作为超声/荧光双模态造影剂的可行性。这种新型超声/荧光双模态造影剂可能在各种生物和医学应用中具有潜力。
