Surface carboxyl groups on polystyrene nanoparticles are able to trigger clathrin-mediated endocytosis and strongly facilitate internalization of negatively charged nanoparticles by mesenchymal stem cells (MSCs).
Specific effects of surface carboxyl groups on anionic polystyrene particles in their interactions with mesenchymal stem cells
Xiue Jiang, Anna Musyanovych, Carlheinz Röcker, Katharina Landfester, Volker Mailänder and G. Ulrich Nienhaus
Nanoscale, 2011, DOI: 10.1039/C0NR00944J
The electron beam of a scanning electron microscope was used to write a polarisation grating onto vertical surface emitting lasers in a maskless, dry, single step process.
Polarisation stabilisation of vertical cavity surface emitting lasers by minimally invasive focused electron beam triggered chemistry
Ivo Utke, Martin G. Jenke, Christian Röling, Peter H. Thiesen, Vladimir Iakovlev, Alexei Sirbu, Alexandru Mereuta, Andrei Caliman and Eli Kapon
Nanoscale, 2011, DOI: 10.1039/C1NR10047E
Nanoscale Editorial Board member Molly Stevens (Imperial College London) gave a talk at the Annual Biophysical Society meeting yesterday.
This was the first time Professor Stevens had been invited to talk at the Biophysical Society Meeting, and her lecture on her research into tissue engineering was very well received. Her research focusses on the regeneration of tissue, with a focus on engineering new bone tissue.
She also discussed her collaborative research on sub-nanoscale patterning which she did with Francesco Stellacci’s group (Nanoscale Editor-in-Chief) – find out more about Nanoscale and our Editorial Board at www.rsc.org/nanoscale
Encapsulated enhanced green fluorescence protein in silica nanoparticle for cellular imaging
Zhengwei Cai, Zhangmei Ye, Xiaowei Yang, Yanli Chang, Haifang Wang, Yuanfang Liu and Aoneng Cao
Nanoscale DOI:10.1039/C0NR00956C
Scientists in China have developed a simple method of capping green fluorescent protein (GFP) in silica, which is a vital step in improving the versatility of fluorescent proteins for use as imaging probes.
Cai et al. at Shanghai University developed a covalent attachment route, which means the capping precursors are chemically bonded to the protein, rather than just providing passive encapsulation. The silica shell is then grown from the precursor layer to provide a solid and stable shell. A simple reverse emulsion method was used, and the group achieved a very high encapsulation efficiency and high protein loading. Their characterisation results suggest that encapsulating GFP in silica significantly increases its fluorescence and stability as the capping provides an effective barrier from external interference, such as protease attack, denaturants, and excessive heating.
Fluorescent probes are widely used to image biological structures and processes, both in vivo and in vitro. The main concerns in the design of these probes are their optical properties and the way they interact with their environment. For example, you may have a probe which exhibits excellent optical properties, but is toxic and therefore adversely affects the things you are trying to image. Conversely, you could have a probe which is non-toxic, but is unstable and loses its fluorescence too quickly under excitation. Traditional organic dyes suffered from various problems, including a lack of stability, broad emission profiles and toxicity issues. These have gradually been replaced with modern ‘nanoprobes’ which consist of either fluorescent nanoparticles or nanoparticulate coatings for fluorescent molecules. Of all the nanoprobes developed, fluorescent quantum dots exhibit the best optical properties, however, as they generally contain heavy metals such as cadmium, there are toxicity concerns in many applications.
The silica encapsulated fluorescent protein nanoparticles developed in this work may prove to be an exciting new probe which exhibits excellent optical and stability properties whilst avoiding problems such as toxicity and instability,
To read this article, click here.
Nanoscale DOI:10.1039/C0NR00956C
The Chinese State Council announced yesterday that they have appointed Chunli Bai as the next president of the Chinese Academy of Sciences (CAS).
Professor Bai has been the executive vice president of CAS since 2004, and will take over from former CAS President Lu Yongxiang.
The Nanoscale team would like to congratulate Professor Bai and we wish him all the best in his new role!
A simple, scalable, graphene patterning method has been developed and applied to fabricate CdSe nanobelt/graphene Schottky junction solar cells. A typical as-fabricated solar cell shows an energy conversion efficiency of ~1.25%.
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, DOI: 10.1039/C0NR00999G
Carbon nanotubes can enhance plant growth without damaging plant cells, say scientists from India
Sabyasachi Sarkar and colleagues from the Indian Institute of Technology in Kanpur treated chickpea plants with up to 6ug/ml of water soluble carbon nanotubes. They found that the nanotubes increased the growth rate in every part of the plant – in the roots, shoots and branches.
Sarkar thought that the channels could be replicated by carbon nanotubes. ‘We followed Thomas Edison’s recipe to make carbonised filament from bamboo or wood wool in his electric bulb to get the carbon nanotubes,‘ he adds. ‘Of course, we had to derivatise them to make them water soluble.’ The team achieved this by attaching carboxylic acid groups to the surface of the tubes.
‘The work seems to support the positive effect of carbon nanotubes,’ says Xiaohong Fang, an expert in the use of carbon nanotubes as molecular transporters in plants at the Chinese Academy of Sciences in China. However, she points out that the biological effects on plants may differ depending on the materials’ chemical and physical properties, plant type and cultivation conditions.
Read the rest of the Chemistry World story by Elinor Richards
View the Nanoscale article in full:
Growth stimulation of gram (Cicer arietinum) plant by water soluble carbon nanotubes
Shweta Tripathi, Sumit Kumar Sonkar and Sabyasachi Sarkar
Nanoscale, 2011, DOI: 10.1039/c0nr00722f
This month’s issue includes a collection of articles on the theme surface nanotechnology for biological applications
This themed issue is Guest Edited by Professor Marcus Textor, Professor Darrell Irvine and Professor Xingyu Jiang. It includes a Review by Antonio Nanci et al. on Nanoscale surface modifications of medically relevant metals: state-of-the art and perspectives and a Communication by Molly Stevens, Kinetic investigation of bioresponsive nanoparticle assembly as a function of ligand design, as well as much, much more!
Cover image
The cover image highlights the paper by Nicholas Melosh and colleagues and shows that the stability of nanoscale hydrophobic bands inside the hydrophobic core of lipid membranes depends on their relative size.
Nanoscale patterning controls inorganic–membrane interface structure
Benjamin D. Almquist, Piyush Verma, Wei Cai and Nicholas A. Melosh
Nanoscale, 2011, 3, 391-400
Want to read more about our themed issues? Please visit the ‘ Themed Issues’ page on our website.
Effect of surface charge of polyethyleneimine-modified multiwalled carbon nanotubes on the improvement of polymerase chain reaction
Xueyan Cao, Jingjing Chen, Shihui Wen, Chen Peng, Mingwu Shen and Xiangyang Shi
Nanoscale DOI:10.1039/C0NR00833H
There are a vast number of potential applications for carbon nanotubes in many areas of science today, but current uses are mostly associated with their structural properties in bulk quantities. However, there is a vast amount of research being conducted on how the nanoscale properties of carbon nanotubes can be used to perform precise actions at a molecular level. This concept is of particular interest in biomedical science, where fine control of interactions with biomolecules and biological structures is of great importance in developing new diagnostic and therapeutic techniques.
Considering applications of carbon nanotubes in biology, scientists in China have conducted a systematic study of how the surface charge of multi-walled carbon nanotubes affects their performance as additives in polymerase chain reactions (PCR), which are of high importance in molecular biology. Cao et al. at Donghua University, Shanghai, used polyethyleneimine (PEI)-modified multiwalled carbon nanotubes with different surface charge polarities, and showed that positively charged nanotubes could significantly enhance the specificity and efficiency of PCR, even when used at a low concentration.
Polymerase chain reactions are of fundamental importance in molecular biology as a gene amplification technique, where the copying yield of a targeted gene can be increased drastically. However, the technique suffers from low specificity and efficiency, and therefore optimisation procedures are essential. Unfortunately, as the mechanism is complex, this optimisation is not easily achieved. Nanoparticles have been studied as potential solutions to these problems due to their unique physicochemical properties, and indeed carbon nanotubes have been shown to be good additives for PCR optimization. However, this study in China is the first report relating to the optimization of PCR using CNTs with different surface charge polarities, and it represents an exciting development in the field.
To read the whole article, click here.
Biomineral nanoparticles are space-filling
Li Yang, Christopher E. Killian, Martin Kunz, Nobumichi Tamura and P. U. P. A. Gilbert
Nanoscale, 2011, 3, 603-609
Sea urchin biominerals are known to form from aggregating nanoparticles of amorphous calcium carbonate, which then crystallize into macroscopic single crystals of calcite. The group measured the surface areas of these biominerals, finding them to be comparable to those of space-filling macroscopic geologic calcite crystals. These biominerals are therefore different from synthetic mesocrystals, which are always porous. Based on this results, the group proposes that space-filling amorphous calcium carbonate is the structural precursor for echinoderm biominerals.
Mollusk shells, corals, and echinoderm biominerals have remarkable mechanical properties, making them the object of many studies to shed some light on their formation mechanisms.
Read the whole article now
Article submitted as part of the Themed Issue on Crystallization and Formation Mechanisms of Nanostructures, read the issue here
