Title: Synthesis of high aspect ratio gold nanorods and their effects on human antigen presenting dendritic cells

Authors: Fei Ye, Helen Vallhov, Jian Qin, Evangelia Daskalaki, Abhilash Sugunan, Muhammet S. Toprak, Andrea Fornara, Susanne Gabrielsson, Annika Scheynius, Mamoun Muhammed

Addresses: Functional Materials Division, Royal Institute of Technology (KTH), Kista, 164 40, Sweden. ' Clinical Allergy Research Unit, Department of Medicine Solna, L2:04, Karolinska Institutet and University Hospital Solna, Stockholm, 171 76, Sweden. ' Functional Materials Division, Royal Institute of Technology (KTH), Kista, 164 40, Sweden. ' Clinical Allergy Research Unit, Department of Medicine Solna, L2:04, Karolinska Institutet and University Hospital Solna, Stockholm, 171 76, Sweden. ' Functional Materials Division, Royal Institute of Technology (KTH), Kista, 164 40, Sweden. ' Functional Materials Division, Royal Institute of Technology (KTH), Kista, 164 40, Sweden. ' Functional Materials Division, Royal Institute of Technology (KTH), Kista, 164 40, Sweden. ' Clinical Allergy Research Unit, Department of Medicine Solna, L2:04, Karolinska Institutet and University Hospital Solna, Stockholm, 171 76, Sweden. ' Clinical Allergy Research Unit, Department of Medicine Solna, L2:04, Karolinska Institutet and University Hospital Solna, Stockholm, 171 76, Sweden. ' Functional Materials Division, Royal Institute of Technology (KTH), Kista, 164 40, Sweden

Abstract: High aspect ratio (AR) gold nanorods (NRs) attract great interest for biomedical applications due to their novel physicochemical properties. Here, we report a facile method for preparation of high AR gold NRs through a seedless surfactant-mediated protocol with the additive of nitric acid. High-resolution transmission electron microscopy studies showed that the concentration of nitric acid has great effects on the crystal structures of the initially formed nuclei and consequently the growth of gold NRs. A mechanism based on the effect of nitrate ions on surfactant micelle elongation and Ostwald ripening process is proposed for the growth of high AR gold NRs. The biocompatibility of high AR NRs was evaluated on primary human monocyte derived dendritic cells (MDDCs), and compared with that of spherical gold nanoparticles (NPs) and low AR NRs. Low AR (~4.5) gold NRs induced considerable cell death due to CTAB, while spherical gold NPs (7 nm) and high AR (~21) gold NRs showed no or minor effects on viability and immune regulatory markers, which supports the further development of high AR gold NRs for medical applications.

Keywords: gold nanorods; non-seeded; nitric acid; high aspect ratio; biocompatibility; dendritic cells; immunomodulatory effects; nanotechnology; human antigen; biomedical engineering; bioengineering; crystal structure; surfactant micelle elongation; Ostwald ripening; nanomedicine; medical applications.

DOI: 10.1504/IJNT.2011.041435

International Journal of Nanotechnology, 2011 Vol.8 No.8/9, pp.631 - 652

Published online: 22 Jul 2011 *

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