†School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
‡Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Graz 8010, Austria.
ACS Nano. 2015 May 26;9(5):5275-88. doi: 10.1021/acsnano.5b00771. Epub 2015 Apr 15.
High brightness, chemical and photostability, tunable characteristics, and spectral and surface properties are important attributes for nanoparticle probes designed for live cell imaging. We describe a class of nanoparticles for high-resolution imaging of O2 that consists of a substituted conjugated polymer (polyfluorene or poly(fluorene-alt-benzothiadiazole)) acting as a FRET antenna and a fluorescent reference with covalently bound phosphorescent metalloporphyrin (PtTFPP, PtTPTBPF). The nanoparticles prepared from such copolymers by precipitation method display stability, enhanced (>5-10 times) brightness under one- and two-photon excitation, compatibility with ratiometric and lifetime-based imaging modes, and low toxicity for cells. Their cell-staining properties can be modulated with positively and negatively charged groups grafted to the backbone. The "zwitter-ionic" nanoparticles show high cell-staining efficiency, while their cell entry mechanisms differ for the different 3D models. When injected in the bloodstream, the cationic and anionic nanoparticles show similar distribution in vivo. These features and tunable properties make the conjugated polymer based phosphorescent nanoparticles a versatile tool for quantitative O2 imaging with a broad range of cell and 3D tissue models.
高亮度、化学和光稳定性、可调谐特性、光谱和表面性质是设计用于活细胞成像的纳米粒子探针的重要属性。我们描述了一类用于高分辨率 O2 成像的纳米粒子，它们由取代的共轭聚合物（聚芴或聚（芴-alt-苯并噻二唑））作为 FRET 天线和荧光参比物组成，与共价键合的磷光金属卟啉（PtTFPP、PtTPTBPF）。通过沉淀法从这些共聚物制备的纳米粒子显示出稳定性、在单光子和双光子激发下增强（>5-10 倍）的亮度、与比率和寿命成像模式的兼容性以及对细胞的低毒性。通过接枝到主链上的正电荷和负电荷基团可以调节其细胞染色性质。“两性离子”纳米粒子显示出高的细胞染色效率，而它们的细胞进入机制因不同的 3D 模型而不同。当注入血液时，阳离子和阴离子纳米粒子在体内具有相似的分布。这些特性和可调谐特性使基于共轭聚合物的磷光纳米粒子成为用于定量 O2 成像的多功能工具，适用于广泛的细胞和 3D 组织模型。
