Peptide-functionalized gold nanorods increase liver injury in hepatitis.

Targeted nanomedicine holds enormous potential for advanced diagnostics and therapy. Although it is known that nanoparticles accumulate in liver in vivo, the impact of cell-targeting particles on the liver, especially in disease conditions, is largely obscure. We had previously demonstrated that peptide-conjugated nanoparticles differentially impact macrophage activation in vitro.

Effects of nanoparticle surface-coupled peptides, functional endgroups, and charge on intracellular distribution and functionality of human primary reticuloendothelial cells.

Unlabelled: The medical use of nanoparticles (NPs) has to consider their interactions with the cells of the reticuloendothelial system. In this study the authors used gold nanorods coated by PEG chains bearing peptides or charged functional groups to study their influence on the uptake, subcellular distribution, and activation of human primary reticuloendothelial cells: monocytes, macrophages (MΦ), immature and mature dendritic cells (DC), and endothelial cells (EC). We found that beside MΦ and immature DC also EC internalize large quantities of NPs and observed an increased uptake of positively charged particles.

Anion effect on the shape evolution of gold nanoparticles during seed-induced growth in imidazolium-based ionic liquids.

The relevance of anion structure on the shape regulating effect of 3-ethyl-1-methylimidazolium-based ionic liquids during the seed-induced growth of gold nanocrystals is evaluated for the particular case of lactate, acetate, methylsulfate, ethylsulfate and tosylsulfonate anion systems. Carboxylate-based anions (lactate and acetate) are found to inhibit the reduction of the gold precursor salt presumably due to the deprotonation of the reducing agent ascorbic acid. The formation of non-uniform, 'head-tail'-type anisotropic particle structures is observed in both methyl- and ethylsulfate anion systems whereas rapid precipitation is observed in the case of tosylsulfonate anions.

Rapid uptake of gold nanorods by primary human blood phagocytes and immunomodulatory effects of surface chemistry.

Nanoparticle-based in vivo applications should consider the omnipresence of the phagocytes in the bloodstream and tissue. We have studied the nanoparticle uptake capacities of the most important human primary leukocyte populations using a nanoparticle library encompassing both rod-shaped and spherical gold nanoparticles with diameters between 15 and 50 nm and a variety of surface chemistries. Cetyltrimethylammoniumbromide (CTAB)-stabilized nanoparticles were internalized rapidly within 15 min and in large amounts by macrophages and to a lower extent also by monocytes.

Phagocytosis independent extracellular nanoparticle clearance by human immune cells.

It has recently been discovered that human immune cells, especially neutrophil granulocytes, form neutrophil extracellular traps (NETs) that abolish pathogens. Our study provides evidence that extracellular traps formed by neutrophils, monocytes and macrophages act as physical barriers for nanoparticles, thus presenting a new nanomaterial clearance mechanism of the human immune system. While particle shape is of minor importance, positive charges significantly enhance particle trapping.

Structural evolution of gold nanorods during controlled secondary growth.

Single-crystalline gold nanorods synthesized by the Ag(I)-mediated seeded-growth method (see: El-Sayed, M. A.; Nikoobakht, B.