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 this website μg/ml). Exposure to AuNP Au[(Gly-Tyr-TrCys)2B] also resulted in a reduction in viability over time but not below LY2874455 clinical trial 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 Selleckchem YH25448 < 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 covered almost the entire well (Figure 10f). While this phenomenon made it difficult to view Non-specific serine/threonine protein kinase 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.