The gold nanorods, conjugated to anti-EGFR and suggested by Huang et al, are particularly promising due to their potential application in both cancer diagnosis and treatment – all nanostructure applications discussed so far have been in cancer therapy only. To test the potential application in cancer diagnosis, three types of cell were incubated with anti-EGFR/gold nanorods and anti-EGFR/gold nanospheres – healthy HaCaT cells (keratinocyte cells found in the epidermis), cancerous HSC cells (hematopoietic stem cells) and cancerous HOC cells (human ovarian carcinoma cells). These cells, incubated with the anti-EGFR/gold nanostructures, were subjected to dark field microscopy in order to scatter light and produce the following images.

Figure 16: Dark field microscopy images of HaCaT, HSC and HOC cells after incubation with anti-EGFR/gold nanospheres (A) and anti-EGFR/gold nanorods. The gold nanospheres strongly scatter green and yellow light, and the gold nanorods strongly scatter red and orange light.
The images above show clearly that both the nanospheres and nanorods bind more strongly to the cancerous cells than the healthy HaCaT cells, and that gold nanorods are more effective at this than gold nanospheres. The clear visual difference in binding means that this is a promising application in the diagnosis of cancer.
In the figure above, it can be seen that at a laser power of 80mW, both HSC and HOC cells incubated with anti-EGFR/gold nanorods begin to suffer damage, and the HaCat cells incubated with anti-EGFR/gold nanorods do not suffer any damage until treatment with a laser of power 120mW. These results are promising as it shows the selectivity of anti-EGFR/gold nanorods in only harming cancerous cells and not normal, healthy tissue. As with several studies previously discussed, however, these results come from an in vitro experiment and should not be taken as confirmation that the same selectivity would be shown inside the human body, or that the nanorods would be as effective in destroying cancerous cells. However, the potential application in cancer diagnosis may not require further in vivo t