Fig. 9

a ¹¹¹In-trastuzumab-AuNPs are an example of an Auger electron (AE)-emitting radiation nanomedicine composed of gold nanoparticles (AuNPs; 30 nm) modified with 2 kDa polyethylene glycol (PEG) chains to stabilise the AuNPs and longer 5 kDa PEG chains conjugated to trastuzumab to bind HER2 or to DTPA to complex ¹¹¹In. b Dark-field and fluorescence microscopy demonstrating peri-nuclear localisation (nucleus is stained blue with DAPI) of ¹¹¹In-trastuzumab-AuNPs (yellow) in HER2-positive SK-BR-3 human breast cancer cells likely mediated by an endogenous nuclear localisation sequence (NLS) peptide in HER2. c DNA double-strand breaks (DSBs; bright foci) detected by immunofluorescence for γH2AX in the nucleus of SK-BR-3 cells exposed to ¹¹¹In-trastuzumab-AuNPs mediated by emission of AEs by ¹¹¹In. d Local intratumoural (i.t.) injection of ¹¹¹In-trastuzumab-AuNPs (10 MBq) in athymic mice with subcutaneous HER2-positive MDA-MB-361 human breast cancer xenografts arrested tumour growth compared to untreated mice (left panel) with no change in body weight (right panel) indicating no generalised normal tissue toxicity (Cai et al. 2016)