Using "living" PEGylation the team, led by Duxin Sun, conjugated the modal targeting peptide RGD (HS-PEG-RGD) at different densities to AuNPs that were 20 nm in size. The researchers compared AuNP uptake in target U87-MG glioblastoma cells and non-target (MCF-7) cells using inductively coupled plasma optical emission spectrometry.

The experiments reveal that the targeting ligand/AuNP ratio (50/1) is critical to balancing AuNP specific uptake by cancer cells, and non-specific uptake by non-target cells, while minimizing uptake by macrophage cells.

The researchers also sequentially conjugated HS-PEG-COOH and HS-PEG-NH2 to the gold nanoparticles at different densities to develop double-charged AuNPs. Macrophage cells take up fewer of these nanoparticles compared to single-charged or non-charged AuNPs, an affect that is perpetuated as the overall charge of double-charged AuNPs becomes more neutral.

Applying "living" PEGylation to precisely control gold nanoparticle functionalization for cancer therapy can enhance nanoparticle targeting to cancer cells, reduce side effects from uptake by non-target cells, and minimize recognition by immune cells. We believe that such findings merit further in vivo studies of AuNPs containing an optimal density of a charged targeting ligand and a releasable, oppositely charged drug.

More information can be found in the journal Nanotechnology 24 355101.

Further reading

Cyto-friendly system for targeted cancer imaging (Feb 2010)
Highly stable magnetic nanoparticles for targeting cancer cells (Oct 2007)
Nanostars target cancer cell nuclei (Apr 2012)
Nanoparticles boost radiotherapy efficacy (Feb 2011)