Amperometric response for AuNP immunosensor incubated with IL-8 (concentration labeled on curves) or conditioned media containing IL-8 secreted by human squamous cells. Conditioned media samples from HNSCC cell lines (HEp2, HN13, OSCC3, Cal27), immortalized epidermal (HaCaT) and mucosal (NOKsi) squamous cells, and serum-free (SF) media were analyzed using biotinylated Ab2 (10 μL, 0.05 μgmL−1) in 0.1% BSA in pH 7.2 PBS buffer and streptavidin-modified HRP (10 μL). A) Current at −0.3 V and 2000 rpm using hydroquinone mediator in PBS buffer, after injecting H2O2 to 0.4 mM. B) AuNP sensor results for conditioned media shown with results from ELISA of the samples.