The Effect of Internalized Paramagnetic Nanoparticles on Caenorhabditis elegans Locomotion in the Presence of Magnetic Field

Figure 3

Confirmation of nanoparticles uptake in young adult C. elegans. (a) Internalization of 1 μm paramagnetic particles is verified by bright field microscopy. Left: worm fed with plain E. coli OP50 (control, Group C). Right: worm fed with E. coli OP50 mixed with 1 μm particles. Particles appear to be aggregated in the dark-colored pharynx (PHX) and intestine (INT) of Group 1 worms, in contrast to the light-colored PHX and INT of Group C worms. Scale bar: 0.1 mm. (b) Internalization of 100 nm magnetic, fluorescent nanoparticles is verified by epifluorescent microscopy. Top panels: worm fed with plain E. coli OP50 (control, Group C), bottom panels: worm fed with E. coli OP50 mixed with 100 nm particles. Bright light: worms illuminated by bright light source; rhodamine: worms visualized with optical filter for rhodamine, Excitation 545 nm/Emission 565 nm; GFP: worms visualized with optical filter for green fluorescent protein (GFP), Excitation 395 nm/Emission 510 nm; DAPI: worms visualized with optical filter for DAPI, Excitation 358 nm/Emission 460 nm. In GFP and DAPI images, autofluorescence is the only fluorescence detected. Scale bar: 0.1 mm. (c) Internalization of 40 nm paramagnetic particles is verified by scanning electron microscopy (SEM). Left: a whole C. elegans as captured by SEM, using Everhart–Thornley SE detector. Center: 40 nm particles, shown as white dots, detected close to C. elegans PHX, using circular backscatter (CBS) detector, magnification 1,500×. Right: 40 nm particles, shown as white dots, detected close to C. elegans PHX, using CBS detector, magnification 3,000×. Location of particles is approximate due to distortion generated during sample processing.

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