By imaging Cy5-labeled BSA@pSiNP and Tf@pSiNP in exposed cells using confocal microscopy, higher fluorescence intensity of Cy5-Tf@pSiNP (3 fold) was identified in the cytoplasm of GBM cells as compared to those exposed to Cy5-BSA@pSiNP (Fig. 1D). The gene discussed is TF; the disease is glioblastoma.