Fig. 1

Schematic representation and characterization of GNRs@PEG-Iso4 and GNRs@PEG-Cys. Representation of the structures of: A head-to-tail cyclized peptide Iso4, B lipoic acid-PEG-maleimide heterobifunctional cross-linker (LA-PEG-MAL) containing a PEG chain of 5KDa, C and gold nanorods (GNRs) functionalized with peptide Iso4 (GNRs@PEG-Iso4) or Cys (GNRs@PEG-Cys) via LA-PEG-MAL. D UV-IR absorption spectra of the GNRs@PEG-Iso4 and GNRs@PEG-Cys. The dotted line corresponds to the uncoated gold nanorods (GNRs). E Representative microphotographs of GNRs@PEG-Iso4 and GNRs@PEG-Cys, as determined by transmission electron microscopy (TEM). F Binding of GNRs@PEG-Iso4 and GNRs@PEG-Cys to plates coated with or without α5β1-integrin. The binding of nanoparticles was detected with an anti-PEG rat antibody followed by HRP-labelled goat anti-rat antiserum. Mean ± SE of technical duplicates. G Binding of GNRs@PEG-Iso4 and GNRs@PEG-Cys to bladder cancer MB49-Luc cells as determined by FACS. MB49-Luc cells in suspension were incubated with the indicated amounts of nanoparticles for 1 h on ice. After washing, the cells were incubated with an anti-PEG antibody (0.5 h on ice) followed by a FITC-labelled secondary antibody (0.5 h in ice). The bound fluorescence was quantified by flow cytometry analysis. Representative FACS plots (left) and dose-dependent binding curves (right) (dots, mean ± SE of technical triplicates) are shown