Compound cellular imaging of laser scanning confocal microscopy by using gold nanoparticles and dyes

Combining the scattered light of gold nanoparticles ( GNPs) and the fluorescence of dye molecules, a compound cellular imaging of laser scanning confocal microscopy ( LSCM) is obtained. The human breast cancer cell line ( MDA-MB-435S, BCRC 60429) is used for experiment. These cells are incubated with a glucose medium containing GNPs for 26 hours, and then are stained by Prodium Iodide ( PI) for their nuclei. By using a single laser to illuminate these cells and adjusting the ranges of two bandpass filters for the detection, the scattered light from the GNPs and the fluorescence of PI can be induced simultaneously, but be detected separately without crosstalk. Furthermore, a compound cellular image can be obtained by merging the two images of the expressions of GNP and PI together. From the TEM images of these cells, it is observed that GNPs are aggregated in the vesicles of the cytoplasm due to the cell's endocytosis. The aggregation of GNPs makes the surface plasmon resonance band of GNPs broadened, so that strong scattered light from GNPs can be generated by the illumination of different-wavelength lasers ( 458, 488, 514, 561, and 633 nm).