Engineering bioconjugated gold nanospheres and gold nanorods as label-free plasmon scattering probes for ultrasensitive multiplex dark-field imaging of cancer cells.

In this paper, we proposed the use of gold nanoparticles as plasmon scattering probes for dark-field multiplex imaging of live cancer cells. By carefully engineering the surfaces, aqueous dispersions of anti-EGFR antibody-conjugated gold nanospheres and gold nanorods are prepared. We demonstrated the receptor-mediated delivery of antibody conjugated gold nanospheres and gold nanorods into EGFR receptor-positive oral squamous cell carcinoma cell line by using dark-field microscopy technique. Our result suggests that gold nanospheres and gold nanorods formulations could provide up to 7 types of plasmon scattering probes based on their tunability range with a 100 nm spectral separation in absorption bands.