Colloidal gold nanoparticle conjugates of gefitinib

Gefitinib (GF) is a US Food and Drug Administration-approved epidermal growth factor receptor (EGFR)tyrosine kinase inhibitor for treating the lung cancers. We fabricated colloidal gold nanoparticle (AuNP) conjugates of the GF anticancer drug by self-assembly to test their potency against A549, NCI-H460, and NCI-H1975 lung cancer cells. GF adsorption on AuNP surfaces was examined by UV vis absorption spectra and surface-enhanced Raman scattering. Density functional theory calculations were performed to estimate the energetic stabilities of the drug-AuNP composites. The N1 nitrogen atom of the quinazoline ring of GF was calculated to be more stable than the N3 in binding Au cluster atoms. The internalizations of GF-coated AuNPs were examined by transmission electron and dark-field microscopy. A cell viability test of AuNP GF conjugates with the EGFR antibody exhibited much higher reductions than free GF for A549, NCI-H460, and NCI-H1975 lung cancer cells after treatment for 48 h. (C) 2014 Elsevier B.V. All rights reserved.We would like to thank Semi Kim for her help on TEM measurements. SWJ, Prof. So Yeong Lee, and KL thank Dr. Kyong-Ah Yoon for their helpful comments on the EGFR mutations. Prof. K. Cho acknowledges the support by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry & Energy (No. 20124030200070). Prof. D. Kim acknowledges support from the Korea government (MEST) No. 2011-0031496. Prof. J. Choo acknowledges that the Nano Material Technology Development Program supported this work through the National Research Foundation of Korea, funded by the Ministry of Education, Science, and Technology (grant number 2012035286)