中文摘要：

使用阳离子胶体金标记中国仓鼠卵巢细胞（CHO-K1）的阴离子位点,并采用双光子荧光显微成像和荧光寿命成像技术记录活细胞的阴离子场分布.阳离子胶体金是纳米量级金微粒与多聚L-赖氨酸的结合物,金纳米微粒在超短激光脉冲的照射下可以产生高度局域化的光热效应.当飞秒激光脉冲聚焦在细胞膜上标记的金纳米微粒时会产生这种纳米尺度的微光热效应,并在不影响细胞活性的前提下暂时提高细胞膜的通透性.基于这种效应,使用聚焦的飞秒激光脉冲三维扫描照射CHO-K1细胞,将分子质量为10ku的荧光探针大分子异硫氰酸荧光素葡聚糖（fluorescein isothiocyanate-dextran,FITC-D）递送到CHO-K1细胞的内部,并用双光子荧光图像记录其递送的过程.使用流式细胞仪分析不同实验条件下FITC-D的转导率和细胞死亡率的关系.

英文摘要：

Cationic colloidal gold （CCG） nanoparticles were used for labeling on the anioinic sites of living cells under two-photon fluorescence （TPF） microscope, and for delivering macromolecules into the target cells when irradiated by focused femtosecond laser pulses. 15 nm CCG nanoparticles which were made by conjugation with poly-L-Lysine, were attached on the anionic sites, especially on the membrane, of CHO-K1 cells because of their strong positive charge at physiological pH. Target cells labeled with cationic gold nanoparticles were imaged under TPF microscope, and lifetime images of the same targets were taken by time correlated single photon counting （TCSPC） technique in order to verify the fluorescence of the marker and the luminescence of the gold particles. The results shown that CCG nanoparticles first accumulated on the negatively charged sites of the membrane, then entered via endocytic pathway and attached anionic sites in plasma. A macromolecular 10 ku fluorescein isothiocyanate dextran （FITC-D） was added into the sample and the focused femtosecond laser of TPL microscope was employed to scan the target cells layer by layer. Typical laser power level used in biological imaging is about 3 -5 mW. Here the laser power of scanning was below 5 mW in order to prevent photochemical damage of the fs-pulses alone and to localize effects to the nanoparticles on a nano-scale. After scanning the target cells under stack mode, macromolecular fluoresceins surrounding the cells was observed to cross the membrane and to diffuse in the cytoplasma. Comparing with the images before scanning, the two-photon fluorescence and fluorescence lifetime images revealed the delivery of FITC-D into target cells. Photothermal effects, which may be responsible for the permeabilisation, are highly localized in nanoscale and are not expected to cause damage exceeding the cell membrane. After extensive of laser scanning also cell death occurred. The ratio of the uptake of FITC-D and cellular death under different conditions