Analytical Sciences

Epidermal Growth Factor-gold Nanoparticle Conjugates-induced Cellular Responses: Effect of Interfacial Parameters between Cell and Nanoparticle

Shota YAMAMOTO* and Jun NAKANISHI*,**,***

*Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
**Department of Nanoscience and Nanoengineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
***Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan

The original activity of epidermal growth factor (EGF) is to promote cell growth or block their apoptosis. However, its activity changes to proapoptotic, completely opposite to the original one, upon conjugation to nanoparticles. We have recently identified that this unique activity conversion was mediated by the confinement of EGF receptor (EGFR) within membrane rafts and signal condensation therein. In this study, we investigated the effect of interfacial parameters between the EGF molecule immobilized at the nanoparticle surface and the cell-surface membrane receptors and analyzed how their interactions were transduced to downstream signaling leading to apoptotic responses. We also studied the cell-type selective apoptotic responses and compared them with EGFR expression level to demonstrate the potential of the nanoparticle conjugate as a new type of anti-cancer drug activating EGFR rather than conventional blocking approaches.

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