A significant decrease (p < 0.01) in cell viability was observed for the AuNP Au[(Gly-Trp-Met)2B] only at the highest dose (100 Linsitinib μg/ml). Exposure to AuNP Au[(Gly-Tyr-TrCys)2B] also resulted in a reduction in viability over time but not below interference levels. This observation thus suggests that this AuNP presents increased biocompatibility. Table 3 Cytotoxicity of PBH-capped AuNPs following 24- and 48-h exposure (EMEM/S-), using resazurin assay     Exposure concentration (μg/ml) Exposure

duration AuNP 12.5 25 50 100 Au[(Gly-Trp-Met)2B] 24 h 97 ± 1 97 ± 1* 96 ± 1* 94 ± 0.3** a   Viability (%) 48 h 98 ± 1 98 ± 2 91 ± 1 69 ± 4** a   Measured interference (%) 96 ± 2 95 ± 2 94 ± 4 88 ± 4 Au[(Gly-Tyr-TrCys) 2 B] 24 h 98 ± 1 96 ± 1* 93 ± 1** 90 ± 1**   Viability (%) 48 h 95 ± 2 100 ± 2 95 ± 3 87 ± 2*   Measured interference (%) 96 ± 3 90 ± 6 85 ± 7 76 ± 6 Au[(Gly-Tyr-Met)2B] 24 h 96 ± 1 96 ± 1* 96 ± 1* 91 ± 2** a   Viability (%) 48 h 94 ± 1 91 ± 6* 81 ± 6** 71 ± 5** a   Measured interference (%) 95 ± 2 92 ± 2 90 ± 4 88 ± 4 Au[(Met)2B] 24 h 97 ± 1 96 ± 0.4* 93 ± 0.4** 94 ± 2** a   Viability (%) 48 h 97 ± 1 91* ± 3 88 ± 4** 68 ± 4 ** a   Measured

interference (%) 93 ± 1 91± 91 ± 2 89 ± 5 Au[(TrCys)2B] 24 h 98 ± 1 97 ± 1 92 ±2* 88 ± 1**   Viability (%) 48 h 94 ± 4 93 ± 1 88 ± 2 ** 77 ± 1**   Measured interference (%) 95 ± 1 93± 91 ± 3 87 ± 4 Also shown are the measured interferences in percent (%) of the control. Average values of three independent measurements are presented (mean ± SEM). Bold emphasis is used to signal the most stable AuNP; *P < 0.05 and **P Pevonedistat datasheet < 0.01, significant differences from control values. aSignificant differences between response to 24- and 48-h exposure. Images of cell condition An optical microscope was used to view the cells and NPs in EMEM/S- at various time points throughout the exposure. The study was performed only for exposures using EMEM/S- because of evidence of higher instability and toxicity of AuNPs under these conditions. Figure 10 shows Hep G2 cells after 24 h of incubation with NP concentrations of 100 μg/ml. The AuNPs Au[(Met)2B] formed large agglomerates

that PD0332991 covered almost the entire well (Figure 10f). While this phenomenon made it difficult to view Methocarbamol the cells, evidence of cell rounding was observed when compared to the untreated cells (Figure 10a). However, the cells most dramatically affected were those exposed to Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B] (Figure 10d,g, respectively). Unique and distinct dark assemblages in the cells exposed to Au[(Gly-Tyr-TrCys)2B] (Figure 10d) were evident. The size of Au[(Gly-Tyr-TrCys)2B] agglomerates did not permit NP visualisation in a cell-free Au[(Gly-Tyr-TrCys)2B] suspension (Figure 8). This observation led us to believe that the assemblies, visible when Au[(Gly-Tyr-TrCys)2B] was in contact with cells (Figure 10d), are a result of cell damage or are formed from cellular interaction with these AuNPs.