Cfi plan fluor 40x

A sketch of the experimental setup is shown in Figure 4. A 660 nm laser beam (Laser Quantum, Opus 660) was expanded with a 5× beam expander (Thorlabs, GBE05-A) and directed to a Nikon inverted microscope (Nikon, Ti-E) with a 100× oil objective (Nikon, CFI Plan Fluor 100XS Oil) for the manipulation experiments inside a microfluidic chamber of ∼120 μm thickness. A Nikon upright microscope (Nikon, Eclipse Ni) with 40× air objective (Nikon, CFI Plan Fluor 40X) was used for automated manipulation experiments. For the dark-field optical imaging, an air condenser (Nikon, C-AA Achromat/Aplanat Condenser) was used to focus the incident white light onto the sample from the top. A complementary metal-oxide-semiconductor (CMOS) camera (Nikon, DS-Fi3) or a charge-coupled device (CCD) camera (Lumenera, 12 fps) was used to record the optical images. A Notch filter (658 nm) was placed between the objective and camera to block the incident laser beam. White light was directed from the top (bottom for the upright microscope) of the stage for bright-field imaging. A xenon lamp (Sutter Instrument Lambda, LB-LS/30) was applied through the objective with a GFP filter cube (457–487/502–538 nm for excitation/emission) for fluorescence imaging. The notch filter was removed in fluorescence imaging. The dichroic beam splitter was selected according to the excitation, emission, and laser wavelength.