Recognition and transmembrane delivery of bioconjugated Fe2O3@Au nanoparticles with living cells

Abstract

Here, we describe the synthesis of peptide- and/or protein-functionalized Fe₂O₃ core–Au shell (Fe₂O₃@Au) nanoparticles for imaging and targeting of living cells. When functionalized with the transmembrane peptide RRRRRRRR (R₈), the Fe₂O₃@Au nanoparticles (R₈-Fe₂O₃@Au) are able to serve as cellular trafficking agents with excellent biocompatibility. The internalization mechanism and delivery efficiency of the R₈-Fe₂O₃@Au nanoparticles have been characterized with dark-field microscopy and fluorescence confocal scanning laser microcopy. Experimental result suggests that the R₈-Fe₂O₃@Au nanoparticles are internalized initially by binding with the membrane-associated proteoglycans on cell surfaces, especially heparan sulfate proteoglycans (HSPGs), following an energy-dependent endocytosis process to enter into living cells. After conjugation with the epidermal growth factor receptorantibody (anti-EGFR), these nanoparticles can also be used for the recognition of cell membrane antigens to specifically label tumor cells.