We first performed biodistribution studies in non-tumor-bearing mice using NPs that were functionalized with a 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG2K) linker conjugated with Cy5.5-Transferrin (Tf-NP) or DSPE-PEG2K-Cy5.5-Folate (Fol-NP) to assess their ability to cross the intact BBB. Here, TF is linked to neoplasm.