Nanoscale & Nanoscale Advances Blog

Issue 4, 2011 of Nanoscale is now online, here are just some of the highlights…

Review
Electrostatics at the nanoscale
David A. Walker, Bartlomiej Kowalczyk, Monica Olvera de la Cruz and Bartosz A. Grzybowski, Nanoscale, 2011, 3, 1316

Feature article
Supramolecular assembly/reassembly processes: molecular motors and dynamers operating at surfaces
Artur Ciesielski and Paolo Samorì, Nanoscale, 2011, 3, 1397

‘HOT’ Communication
A simple and scalable graphene patterning method and its application in CdSe nanobelt/graphene Schottky junction solar cells
Yu Ye, Lin Gan, Lun Dai, Yu Dai, Xuefeng Guo, Hu Meng, Bin Yu, Zujin Shi, Kuanping Shang and Guogang Qin, Nanoscale, 2011, 3, 1477

Issue 4’s front cover features the review by Luis M. Liz-Marzán on controlled assembly of plasmonic colloidal nanoparticle clusters (DOI: 10.1039/C0NR00804D).

Browse the whole issue today online.

Scientists in China have developed a simple method for time-lapse imaging of single molecule reactions in situ by using DNA origami as a reaction surface.

The team recorded the whole dynamic process of the streptavidin–biotin binding reaction. They found that at a streptavidin concentration of 7.6 nM, the binding ratio increased steadily up to nearly 100% within 30 minutes.

This novel single-molecule reaction detection method, at the nanometre scale, may prove useful to study other macromolecule behavior and reaction kinetics, say the researchers.

Reference:
N Wu, X Zhou, D M Czajkowsky, M Ye, D Zeng, Y Fu, C Fan, J Hu and B Li, Nanoscale, 2011, DOI: 10.1039/ c1nr10181a

A team from Canada and the US has demonstrated that InP/ZnS quantum dots show low levels of cytotoxicity in cell lines related to reactive oxygen species production.

Indium phosphide quantum dots have emerged as a less hazardous alternative to cadmium-based particles, but their cytotoxicity has not been well examined, says the team, until now. Although their constituent elements are of very low toxicity to cells in culture, they nonetheless exhibit phototoxicity related to generation of reactive oxygen species by excited electrons and/or holes interacting with water and molecular oxygen, they add.

Using spin-trap electron paramagnetic resonance spectroscopy and reporter assays, the researchers found a considerable amount of superoxide and a small amount of hydroxyl radical formed under visible illumination of biocompatible InP quantum dots with a single ZnS shell, comparable to what is seen with CdTe. A double thickness shell reduces the reactive oxygen species concentration approximately two-fold. Survival assays in five cell lines correspondingly indicate a distinct reduction in toxicity with the double shell InP quantum dots. Toxicity varies significantly across cell lines according to the efficiency of uptake, being overall significantly less than what is seen with CdTe or CdSe/ZnS.

This indicates that InP quantum dots are a useful alternative to cadmium-containing quantum dots, while remaining capable of electron-transfer processes that may be undesirable or which may be exploited for photosensitisation applications, concludes the team.

Read the Nanoscale article today:
H Chibli, L Carlini, S Park, N M Dimitrijevic and J L Nadeau, Nanoscale, 2011
DOI: 10.1039/c1nr10131e