Effect of size and pegylation of liposomes and peptide-based synthetic lipoproteins on tumor targeting

The tumor tissue penetration of liposomes (LIP), pegylated liposomes (PEG-LIP), synthetic high density lipoproteins (sHDL) and pegylated sHDL (PEG-sHDL) were found to be very different when compared in vivo. The sHDL nanoparticles exhibit long in vivo residence time, extravasate through blood vessels, pass through inter-fibrillar openings (<40 nm) of interstitial collagens to penetrate deep into tumor tissues due to its ultra-small size (9.6 nm) and effective cellular uptake mediated by scavenger receptors B-I overexpressed on tumor cells. Tumor tissue penetration and cellular uptake appears to be most effective for sHDL followed by PEG-sHDL, PEG-LIP and LIP.236