Antibody-labeled gold nanoparticles represent a promising novel tool regarding cancer imaging and therapy. Nevertheless, the characterization of biodistribution of such immunonanocarriers has been poorly documented. In this study, the biodistribution of (89)Zr-labeled cetuximab before and after the coupling reaction to gold nanoparticles (AuNPs) was compared and the quantitative imaging performance of (89)Zr immuno-PET was evaluated. Cetuximab was functionalized with the desferal moiety and labeled with (89)Zr ((89)Zr-Df-Bz-NCS-cetuximab). AuNPs with a mean diameter of 5 nm were synthesized according a new method developed in the laboratory, and conjugated to (89)Zr-Df-Bz-NCS-cetuximab using carbodiimide chemistry (AuNPs-PPAA-cetuximab-(89)Zr). The two tracers were injected in A431 xenograft-bearing mice. Tumor and liver uptakes were assessed at different times after injection using quantitative PET imaging. The in vivo specificity of the binding was investigated using a saturating dose of unlabeled cetuximab. Radiolabeled cetuximab was conjugated to AuNPs with a coupling reaction yield >75%. All conjugates were stable in vitro and to a lesser extent in plasma. In vivo distribution studies revealed no significant difference in tumor uptake for cetuximab conjugated to nanoparticles up to 72 h after injection, compared with unconjugated cetuximab. Immuno-PET studies showed that AuNPs-PPAA-cetuximab-(89)Zr provided high tumor-to-background ratio. The liver uptake of AuNPs-PPAA-cetuximab-(89)Zr was higher, compared with (89)Zr-Df-Bz-NCS-cetuximab. In vivo blocking experiments demonstrated selective tumor targeting after coupling reaction. This study showed that the conjugation of AuNPs to cetuximab did not affect its tumor accumulation and that the efficacy of EGFR-targeted nanoparticles was unaltered. The (89)Zr-labeled cetuximab-targeted gold nanoparticles could be a valuable tool for theranostic purposes.

Two borazine derivatives have been synthesised to investigate their self-assembly behaviour on Au(111) and Cu(111) surfaces by scanning tunnelling microscopy (STM) and theoretical simulations. Both borazines form extended 2D networks upon adsorption on both substrates at room temperature. Whereas the more compact triphenyl borazine 1 arranges into close-packed ordered molecular islands with an extremely low density of defects on both substrates, the tris(phenyl-4-phenylethynyl) derivative 2 assembles into porous molecular networks due to its longer lateral substituents. For both species, the steric hindrance between the phenyl and mesityl substituents results in an effective decoupling of the central borazine core from the surface. For borazine 1, this is enough to weaken the molecule–substrate interaction, so that the assemblies are only driven by attractive van der Waals intermolecular forces. For the longer and more flexible borazine 2, a stronger molecule–substrate interaction becomes possible through its peripheral substituents on the more reactive copper surface.

The photophysical properties of some recently synthesized donor-[60]fullerene hybrids, porphyrinyland ferrocenyl-[60]fullerene dyads, are studied by means of absorption, fluorescence and femtosecond transient absorption spectroscopy. The formation of charge transfer states is experimentally confirmed, while it is shown that an efficient photoinduced intra-molecular electron-transfer process takes place between the donors (i.e. porphyrin, ferrocene) and the acceptor (i.e. [60]fullerene). In addition, the transient nonlinear optical response of these [60]fullerene dyads is investigated under visible nanosecond laser excitation. Both dyads were found to exhibit significantly enhanced second hyperpolarizability (g) compared to that of unfunctionalized [60]fullerene, while the refractive part of their nonlinearity dominated their nonlinear optical response in contrast to what has been observed for pristine fullerene and other functionalized fullerenes. Moreover, their optical limiting action is investigated both experimentally and by means of a five-level model. The results are discussed and compared with other literature reports.