Lab of Low-Dimensional Materials Chemistry, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
Biomaterials. 2013 Dec;34(38):10182-90. doi: 10.1016/j.biomaterials.2013.09.044. Epub 2013 Oct 1.
Hydrophilic, fluorescent hybrid nanoprobes (NDI@HNPs) encapsulated with the hydrophobic pH-responsive fluorophore (N,N'-di-n-dodecyl-2,6-di(4-methyl-piperazin-1-yl)naphthalene-1,4,5,8-tetracarboxylic acid diimide, NDI) for recognizing and mapping the route of cell phagocytosis have been fabricated based on the self-assembly of amphiphilic diblock copolymer PS-b-PAA and the subsequent shell cross-linking with 3-mercaptopropyltrimethoxy silane (MPTMS). The as-synthesized NDI@HNPs has a typical spherical morphology of 46 nm in diameter with excellent monodispersity in aqueous solution. The NDI@HNPs probe exhibits extremely low cytotoxicity, fast real time pH response and enhanced fluorescence intensity under acidic environment with respect to the corresponding free dye in highly polar aqueous system because of the encapsulation of NDI molecules inside nanoparticle cores with weak polarity environment. The fluorescence intensity of NDI@HNPs is enhanced by 55-fold upon changing from neutral (pH = 7.4) or basic (pH = 8.4) to acid (pH = 3.4) in aqueous system, in contrast to the serious fluorescence quenching of free NDI in the same medium, which can exactly meet the physiological pH range in cells. The favorably long emission wavelength is beneficial to the low scattering and minimal interfering requirements to fluorescent bioimaging. Moreover, functionalization with rapid cell-penetrating peptides (HIV-1 TAT) allows them to overcome the physiological and biological barriers during the phagocytosis process. Its characteristic fluorescent response to pH benefits the intracellular labeling and organelle targeting, realizing the real time tracking of the probe entry into cancer cells, the accumulation into the endolysosome and the further escape.
基于两亲性嵌段共聚物 PS-b-PAA 的自组装以及随后与 3-巯丙基三甲氧基硅烷 (MPTMS) 的壳交联，制备了封装疏水电荷反转荧光染料 (N,N'-二正十二烷基-2,6-双(4- 甲基-哌嗪-1-基)萘-1,4,5,8-四羧酸二酰亚胺，NDI）的亲水、荧光杂化纳米探针 (NDI@HNPs)，用于识别和绘制细胞吞噬途径。所合成的 NDI@HNPs 具有典型的 46nm 直径球形形态，在水溶液中具有优异的单分散性。与高极性水相体系中相应的游离染料相比，由于 NDI 分子被包裹在具有弱极性环境的纳米颗粒核内，NDI@HNPs 探针在酸性环境下表现出极低的细胞毒性、快速的实时 pH 响应和增强的荧光强度。在水相体系中，从中性 (pH = 7.4) 或碱性 (pH = 8.4) 变为酸性 (pH = 3.4) 时，NDI@HNPs 的荧光强度增强了 55 倍，而在相同介质中游离 NDI 的荧光猝灭严重，这正好满足细胞内的生理 pH 范围。有利的长发射波长有利于荧光生物成像的低散射和最小干扰要求。此外，通过快速穿透细胞的肽（HIV-1 TAT）的功能化使其能够克服吞噬过程中的生理和生物学障碍。其对 pH 的特征荧光响应有利于细胞内标记和细胞器靶向，实现了探针进入癌细胞、在内涵体中积累以及进一步逃逸的实时跟踪。
