Multi-color cell imaging under identical excitation conditions with salicylideneaniline analogue-based fluorescent nanoparticles
Multi-color cell imaging under identical excitation conditions with salicylideneaniline analogue-based fluorescent nanoparticles
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DOI：
10.1039/c4ra10021b
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发表时间：
2014-01-01
期刊：
影响因子：
3.9
通讯作者：
Zhu, Xinyuan
中科院分区：
文献类型：
--
作者：
Deng, Hongping;Liu, Bing;Zhu, Xinyuan
通过缩合反应合成了六种水杨醛缩苯胺衍生物。得益于它们的共面分子构象和分子内氢键，发现其中三种化合物在自组装成直径约为50 nm的纳米颗粒后表现出聚集诱导发射（AIE）或聚集诱导发射增强（AIEE）行为。基于激发态分子内质子转移（ESIPT）性质，这些荧光纳米颗粒（FNP）由于形成H-或J-聚集体而显示绿色、黄色或橙子颜色。有趣的是，源自BMSpP的FNP显示绿色至绿黄色荧光，因为H-聚集体部分转化为J-聚集体。在中性条件（pH = 7.4）下，这些FNP是稳定的，与在pH 5.5下的快速还原相比，120分钟后荧光强度降低小于20%。重要的是，首次报道了源自水杨醛苯胺或其衍生物的FNP的双光子荧光性质。发现绿色、黄色和橙子FNP的双光子吸收截面分别为7、38和27 GM。与磷脂结合后，这些FNP显示出良好的水溶性和低细胞毒性，这使它们成为细胞成像应用的潜在候选者。最后，在相同的激发条件下实现了具有单发射和多发射FNP的多色单元成像。这些结果对于控制此类衍生物的单光子或双光子荧光性质具有重要意义，并为多色细胞成像应用提供了一个有前途的平台。
Six salicylideneaniline (SA) derivatives are synthesized through a condensation reaction. Benefiting from their coplanar molecular conformation and intramolecular hydrogen bonds, three of the compounds are found to exhibit aggregation-induced emission (AIE) or aggregation-induced emission enhancement (AIEE) behavior after self-assembling into nanoparticles that have a diameter of about 50 nm. Based on the excited-state intramolecular proton transfer (ESIPT) properties, these fluorescent nanoparticles (FNPs) display green, yellow or orange colors due to the formation of H- or J-aggregates. Interestingly, FNPs derived from BMSpP show green to green-yellow fluorescence because of the partial transformation of H-aggregates to J-aggregates. Under neutral conditions (pH = 7.4), these FNPs are stable, with the fluorescence intensity decreasing by less than 20% after 120 min, compared to a rapid reduction at pH 5.5. Importantly, a two-photon fluorescence property of FNPs originating from salicylideneaniline or its derivatives is reported for the first time. The two-photon absorption cross-sections of the green, yellow and orange FNPs are found to be 7, 38 and 27 GM, respectively. After conjugation with phospholipids, these FNPs show good water solubility and low cytotoxicity, which make them potential candidates for cell imaging applications. Finally, multi-color cell imaging under identical excitation conditions with single-emissive and multi-emissive FNPs has been achieved. These results are significant for the control of the one- or two-photon fluorescent properties of such derivatives, and provide a promising platform for multi-color cell imaging applications.