Importantly, the presence of the EGFR and PDGFRβ targeting aptamers on the surface of the nanoparticles, either single-targeted (Iren-AuSiO2_CL4 and Iren-AuSiO2_Gint4.T) or dual-targeted (Iren-AuSiO2_CL4_Gint4.T), allowed them to penetrate the mixed tumor/stromal spheroids as qualitatively displayed by the nanoplatform-associated fluorescent signal (visualized in red) that was visible throughout the spheroids. Here, PDGFRB is linked to neoplasm.