Fv500 ix81 confocal microscope

The samples were prepared as described below: A549 cells were seeded in confocal dishes (Corning Co.) and incubated for 24 h. After two washes with preheated D-PBS, the cells were incubated with 250 nM FITC-labeled aptamers in 1 mL of fresh cell medium and 10% FBS for 30 min at 37°C, after which Alexa Fluor 633 conjugated with transferrin from human serum (5 µg/mL, Invitrogen), or LysoTracker Red DND-99 (50 nM, Invitrogen) was added and co-incubated for another 30 min at 37°C. After washing three times with D-PBS, the fluorescence images of internalization were collected on a FV500-IX81 confocal microscope (Olympus America Inc., Melville, NY) with 20× and 100× objectives (Olympus, Melville, NY). Excitation wavelength and emission filters were as follows: FAM, 488 nm laser line excitation, emission BP520_12 nm filter; TAMRA, 543 nm laser line excitation, emission BP580_20 nm filter; Alexa 633, 633 nm laser line excitation, emission LP650 filter.

All cellular fluorescence images were collected on a FV500-IX81 confocal microscope (Olympus America Inc., Melville, NY) with a 40× oil immersion objective (NA = 1.40, Olympus, Melville, NY). A 488 nm argon laser was the excitation source for DOX or FITC dye, and a 543 nm argon laser was used for excitation of TAMRA dye.