Xiao Xudong, Haushalter Jeanne P, Kotz Kenneth T, Faris Gregory W
Biomed Opt Express. 2011 Aug 1;2(8):2255-64. doi: 10.1364/BOE.2.002255. Epub 2011 Jul 13.
We report application of two-photon excitation of europium chelates to immunolabeling of epidermal growth factor receptor (EGFR) cell surface proteins on A431 cancer cells. The europium chelates are excited with two photons of infrared light and emit in the visible. Europium chelates are conjugated to antibodies for EGFR. A431 (human epidermoid carcinoma) cells are labeled with this conjugate and imaged using a multiphoton microscope. To minimize signal loss due to the relatively long-lived Eu(3+) emission, the multiphoton microscope is used with scanning laser two-photon excitation and non-scanning detection with a CCD. The chelate labels show very little photobleaching (less than 1% during continuous illumination in the microscope for 20 minutes) and low levels of autofluorescence (less than 1% of the signal from labeled cells). The detection limit of the europium label in the cell assay is better than 100 zeptomoles.
我们报道了铕螯合物的双光子激发在A431癌细胞表皮生长因子受体（EGFR）细胞表面蛋白免疫标记中的应用。铕螯合物由红外光的两个光子激发并在可见光区发射。铕螯合物与针对EGFR的抗体偶联。用这种偶联物标记A431（人表皮样癌）细胞，并使用多光子显微镜成像。为了将由于Eu(3+)发射寿命相对较长而导致的信号损失降至最低，多光子显微镜与扫描激光双光子激发以及用电荷耦合器件（CCD）进行非扫描检测配合使用。螯合物标记显示出极少的光漂白（在显微镜下连续照射20分钟期间小于1%）和低水平的自发荧光（小于标记细胞信号的1%）。细胞测定中铕标记的检测限优于100zeptomoles。
