双光子敏化Eu3+高效发光活细胞成像纳米生物探针

将Eu(tta)₃dpbt (dpbt: 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine; tta:thenoyltrifluoroacetonato)包埋在甲基丙烯酸甲酯-苯乙烯共聚物、正辛基三甲氧基硅及其水解缩合产物组成的杂化基质中, 制备了Eu(tta)₃dpbt 质量分数为40%的荧光纳米粒子, 其平均粒径为45 nm. 所制备的发光纳米粒子在水中分散稳定性高、光稳定性好、细胞毒性低、长波敏化Eu³⁺发光性能优良, 适宜作为生物分析的发光标记物. 所制备的发光纳米粒子的可见区激发峰位于415 nm, 激发峰尾部延展至475 nm, 其发光量子产率为0.31(λ_ex=415 nm, T=23 ℃), 最大双光子激发作用截面为5.0×10⁵ GM (λ_ex=830 nm, 1 GM=10^-50 cm⁴·s·photo^-1×particle^-1). 以转铁蛋白修饰上述发光纳米粒子表面制备的纳米生物探针被成功应用于活的HeLa肿瘤细胞的特异性标记和双光子激发Eu³⁺发光成像.

Nanoprobes with Enhanced Two-Photon-Sensitized Eu3+ Luminescence Properties for Live Cell Imaging

Luminescent nanospheres (EuPHS, d_av=45 nm) containing 40% (w) of Eu(tta)₃dpbt (tta= thenoyltrifluoroacetonato;dpbt=2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) were prepared by encapsulating Eu(tta)₃dpbt in a hybrid matrix formed in situ from poly(styrene-co-methyl methacrylate), octyltrimethoxysilane, and poly(octylsiloxane). The EuPHS are promising luminescent markers for bioanalysis because of their good dispersibility in aqueous solutions, high photostability, low cytotoxicity, and bright Eu³⁺ luminescence under excitation at long wavelengths. EuPHS exhibited excellent visible light-sensitized and near-infrared two-photon-sensitized Eu³⁺ luminescence properties, with a visible-light excitation peak at 415 nm and an excitation window extending up to 475 nm. The quantum yield for Eu³⁺ luminescence was 0.31 (λ_ex=415 nm, T=23 ℃), and the two-photon excitation (TPE) action cross section was 5.0×10⁵ GM (1 GM=10^-50 cm⁴·s·photo^-1×particle^-1) at 830 nm. Bionanoprobes prepared by adsorbing transferrin on the surfaces of EuPHS were successfully applied in target-specific labeling and two-photon-excitation imaging of live HeLa cells.