Internalization of plasmonic au nanoparticle to investigate the oligomerization and subsequent signalling of intact cells

This photograph originally appeared in the 2014 Research student photography and image competition held to celebrate National Science Week (Aug 16-24). Blurb: Nano-particles are tiny in size 100 nm or downwards, whereas human hair is 10-50 micron diameter hence largest nano-particles are 100 times smaller than a 10 micron human hair. As a particle decreases in size a larger portion of atoms are found at the surface as compared to inside. Thus nano-particle have much larger surface area per unit mass compared to larger particles as a matter of this quantum effect can play a role and these can significantly change materials optical, magnetic and electrical properties. Due to this in recent times, plasmonic metallic nano-particle has gained considerable amount of interest and has been extensively used in cell biology for cancer therapy, drug delivery, disease targeting, biological imaging and probing membrane protein. Here, 80 nm Au nano-spheres were added to the plated HeLa cell media and allowed to sediment. Afterward, migration of nano-particle was observed over time (24 hr) and due to natural process NP was internalized inside HeLa cells forming different types of cluster (different colour such as green ,yellow, orange and red are due to cluster) which was investigated performing the dark field microscopy scattering. This work will pave the way for the cell biologist to consider plasmonic nano-particle as a superior labelling choice and understanding the activation of signalling pathway of intact cells. (Inset: circular shaped different colour tiny things are called nano-particles and random shaped bluish colour things are HeLa cells. Red color square box indicates 10 µm scale bar)