Binding of EGF and EGF-conjugated HAOA-coated gold nanoparticles to EGFR, present on the cell membrane of A549 human lung carcinoma cells, was monitored using confocal fluorescence microscopy and cytotoxicity assays (MTT) were carried out in non-cancerous human immortalized keratinocytes, HaCaT cell line. The gene discussed is EGF; the disease is lung carcinoma.