Conclusions Here, we prepared AuNPs
using several PBHs as capping agents and studied the influence of the structure of these agents on the physico-chemical state and biocompatibility of the resulting NPs. All the AuNPs tested showed excellent dispersibility in water and form stable agglomerates under culture conditions when serum was present. One PBH-capped AuNP preparation, namely (Au[(Gly-Tyr-TrCys)2B]), showed unique physico-chemical properties presenting agglomerates (approximately 200 nm) that remained in the same size distribution under cell culture conditions as when suspended in water, even in the absence of serum. MLN8237 Interestingly, these AuNPs elicited the highest oxidative stress response, with evidence of a unique biological interaction that did not lead to a reduction in Hep G2 cell viability after 48 h of exposure. Our findings suggest that these particular PBH-capped AuNPs exerts a distinct effect on the Hep G2 cell line that is governed by their particular conformation, which is controlled by the chemical structure of their capping agent (Gly-Tyr-TrCys)2B. Given the distinct cellular morphology after exposure to these AuNPs and previous reports of AuNP mechanisms of interactions with biological systems, we propose that the Hep G2 cells undergo a cell survival mechanism of autophagy upon exposure to these AuNPs, thus supporting the notion of a cellular interaction/internalisation
of these AuNPs. Given the relevance of interaction/internalisation, further research efforts should address the applicability of these AuNPs in drug delivery
systems. OICR-9429 clinical trial Acknowledgements This research was performed under the Environmental ChemOinformatics (ECO) Marie Curie Initial Training Network (ITN) programme, SIS3 mouse funded by the Seventh Research Framework Programme (FP7) of the European Union (238701). We also thank Mapfre research grants 2010, the Spanish Ministry of Economy and Competitiveness (MINECO project CTQ 2010–19295) and the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (Project AT 2011–001) for financial support. Electronic supplementary material Additional file 1: Synthesis of PBHs. (PDF 250 KB) Additional file 2: Figure S1: 1H NMR spectrum of free PBH (Met)2B (top) in DMSO-d6 and 1H NMR spectrum of AuNP Au[(Met)2B] (bottom) in D2O. (PDF 92 KB) Montelukast Sodium Additional file 3: Figure S2: UV–vis absorption spectra of AuNPs (a) Au[(Gly-Tyr-Met)2B], (b) Au[(Gly-Tyr-TrCys)2B], (c) Au[(Gly-Trp-Met)2B], (d) Au[(Met)2B] and (e) Au[(TrCys)2B], in water and EMEM/+, each at a concentration of 100 μg/ml and a different time 0, 2, 4 and 24 h after incubation at 37°C. (PDF 201 KB) References 1. Ghosh P, Han G, De M, Kim CK, Rotello VM: Gold nanoparticles in delivery applications. Adv Drug Deliv Rev 2008, 60:1307–1315.CrossRef 2. Dreaden EC, Mackey MA, Huang X, Kang B, El-Sayed MA: Beating cancer in multiple ways using nanogold. Chem Soc Rev 2011, 40:3391–3404.CrossRef 3.