Nanoscale & Nanoscale Advances Blog

Copper has been identified as a critical factor in Alzheimer’s disease due to its involvement in amyloid-β (Aβ) related toxicity, although the mechanism for this has not been understood.

Now Yan-Mei Li and co-workers have shown that while copper does not affect Aβ40, it significantly affects the aggregation Aβ42, enhancing the cytotoxicity of this protein. Aβ42 forms strong interactions with the copper causing it to change conformation to form highly toxic Aβ42 oligomers.

Stopping these Aβ42–copper interactions could therefore provide a promising therapy for Alzheimer’s disease.

Read this HOT Nanoscale article in full:

Copper inducing Aβ42 rather than Aβ40 nanoscale oligomer formation is the key process for Aβ neurotoxicity
Lu Jin, Wei-Hui Wu, Qiu-Ye Li, Yu-Fen Zhao and Yan-Mei Li
Nanoscale, 2011
DOI: 10.1039/C1NR11029B

Single walled carbon nanotubes (SWNTs) hold much promise for biomedical applications due to their unique optical response upon absorption of near-IR light.

In order to make these SWNTs biocompatible, scientists in Japan have designed a SWNT/DNA hybrid which can be coated with cationic poly(L-lysine) grafted with polyethylene glycol. The overall system shows good uptake in cells compared to the same system in the absence of polyethylene glycol.

The authors are now extending their experiments to a mouse cancer model.

Read this HOT Nanoscale article in full:

Enhanced cell uptake via non-covalent decollation of a single-walled carbon nanotube-DNA hybrid with polyethylene glycol-grafted poly(L-lysine) labeled with an Alexa-dye and its efficient uptake in a cancer cell
Tsuyohiko Fujigaya, Yuki Yamamoto, Arihiro Kano, Atsushi Maruyama and Naotoshi Nakashima
Nanoscale, 2011
DOI: 10.1039/C1NR10635J

Spherical silica micro/nanomaterials have great potential to be used as carriers in biological medical and catalytic applications.

In their Nanoscale review article Xin Du and Junhui He describe recent developments in the synthesis of these materials, discuss their applications and look forward to the challenges of the future in this exciting research field.

Read this HOT Nanoscale review:

Spherical silica micro/nanomaterials with hierarchical structures: Synthesis and applications
Xin Du and Junhui He
Nanoscale, 2011
DOI: 10.1039/C1NR10660K

The modification of gold nanoparticles using a specific number of strands of DNA allows them to be manipulated in a more controlled manner. In their interesting Feature article Liu et al. discuss developments in this approach and offer some perspectives on future challenges and opportunities in the field.

Read the full Feature article:

DNA discrete modified gold nanoparticles
Tao Zhang, Zhongqiang Yang and Dongsheng Liu
Nanoscale, 2011
DOI: 10.1039/C1NR10882D

Graphene-modified TiO₂ nanosheet composites with 0.2–2.0 wt% graphene, prepared by a microwave-hydrothermal method, exhibit an enhanced photocatalytic H₂-production activity.

This work shows the possibility that low cost graphene sheets as a substitute for noble metals (e.g. Pt) could be used in the photocatalytic production of hydrogen. The results also demonstrate significant enhancement in the H₂-production activity by using metal-free carbon material as an effective co-catalyst.

Read the Nanoscale article:

Enhanced photocatalytic H2-production activity of graphene-modified titania nanosheets
Quanjun Xiang, Jiaguo Yu and Mietek Jaroniec
Nanoscale, 2011, DOI: 10.1039/C1NR10610D

Scientists in China have developed a quick and easy procedure for preparing 3D graphene in water, enhancing graphene’s properties so that it can be used in supercapacitors, to store hydrogen and as a catalyst support.

Graphene, a single sheet of carbon atoms patterned in a honeycomb lattice can, via self-assembly, form 1D and 2D structures that have many potential applications. However, the graphene obtained is usually small, which limits its use as a functional material. 3D microporous and mesoporous carbon materials (hydrogels and aerogels) are lightweight; have high porosities and storage capacities; large surface areas; high electrical conductivity and thermal stability. Preparing such structures is challenging under mild conditions and current methods are not scalable or cost efficient.

Lifeng Yan and colleagues at the University of Science and Technology of China, Heifei, have prepared 3D graphene structures by self-assembly from graphene oxide using mild chemical reduction in water at 95 degrees Celsius at atmospheric pressure without stirring. The graphene shapes were controlled by using reactor vessels of differing shapes. The team were able to produce cylinder-, pear- and sphere-like shapes. ‘The process is quite simple – any macroscopic 3D graphene shapes can be prepared at room temperature and pressure,’ explains Yan.

In tests, the team found that the materials had high electrical conductivity, and high mechanical and thermal stability. The values for specific capacitance were similar to graphene hydrogels prepared by a hydrothermal method. The materials’ mechanical stability, measured by a compression test, was comparable to chemically cross-linked polymer hydrogels.  

Yan’s team plans to investigate the applications of their materials in super-capacitance, biosensors and catalysis, as well as preparing different types of novel 3D graphene composites.  

‘These macroscopic multi-pore materials will be very interesting if they can be used for reducing greenhouse gases by developing new catalysts,’ says Xiaobo He, an expert in graphene materials at Louisiana State University, US.

Carl Saxton

Read the Nanoscale paper in full:

In situ self-assembly of mild chemical reduction graphene for three-dimensional architectures
Wufeng Chen and Lifeng Yan, Nanoscale, 2011
DOI: 10.1039/c1nr10355e