A pen that performs 3D printing on the nanoscale has been developed by scientists in South Korea.

The pen, created by Seongpil Hwang of Korea University and co-workers, amalgamates the precision of atomic force microscopy with a diffusion limited current from a microscopic electrode.

Contact between the pen's tip and a working electrode creates a localised electroactive area for precise electrodeposition

At its tip, the pen has a microscopic hydrogel pyramid, the sharp apex of which is soaked in an electrolyte for electrochemical reactions. A nanometre-scale area for reactant mass transport results from contact between this tip and an ultramicroelectrode. Controlling this contact with a nanopositioning system regulates a faradaic reaction that enables electroplating to give precise nanostructures; in this case 3D structures of platinum were deposited on a gold electrode – some with dimensions less than 100nm.

To read the full article visit the Chemistry World website.

The paper is free to read in Nanoscale until 13 January 2015:

Hydrogel Pen for Electrochemical Reaction and Its Applications for 3D Printing
Hosuk Kang, Seongpil Hwang and Juhyoun Kwak, Nanoscale, 2015, DOI: 10.1039/C4NR06041E

Researchers in China are hoping to expand the unconventional applications of graphene with their introduction of graphene springs that can function as actuators.

Springs are fundamental components in numerous electronic and mechanical systems. Most commercial springs are made of metal. Carbon-based springs, however, are less advanced, but have the potential to be a lightweight option if their poor elasticity can be tackled.

Now, graphene springs made by Liangti Qu and colleagues, at the Beijing Institute of Technology, succeed where traditional carbon-based springs have failed.

Interested to know more? Read the full news article by Jennifer Newton in Chemistry World here…

Read the article by Liangti Qu, Huhu Cheng, Yuan Liang, Fei Zhao, Yue Hu, Zelin Dong and Lan Jiang in Nanoscale:

Functional Graphene Springs for Responsive Actuation
Liangti Qu, Huhu Cheng, Yuan Liang, Fei Zhao, Yue Hu, Zelin Dong and Lan Jiang
DOI: 10.1039/C4NR03409K, Communication

Implantable medical devices of the future could be built from a new material that is made by layering bacterial cellulose hydrogels with conducting polymers.

Bacterial cellulose (BC) is a naturally occurring polymer hydrogel that is flexible and known to respond to environmental changes. Guang Yang and co-workers at Huazhong University of Science and Technology in Wuhan, China, added a layer of conductive polymer polyaniline (PAni) onto a BC hydrogel to give a material that responds to electrical signals.

The base cellulose hydrogel is made by Gluconacetobacter xylinum bacteria. After purification, the hydrogel is soaked for 48 hours in a solution of salts and aniline monomers. The gel is then sandwiched between two electrodes, and applying an electrical current causes the monomers to form a polymer film layer.

Interested to know more? Read the full news article by Cally Haynes in Chemistry World here…

Read the article by Zhijun Shi, Ying Li, Xiuli Chen, Hongwei Han and Guang Yang in Nanoscale:

Double networks bacterial cellulose hydrogel to build a biology–device interface
Zhijun Shi, Ying Li, Xiuli Chen, Hongwei Han and Guang Yang
DOI: 10.1039/C3NR05214A, Paper

Scientists have designed a grid of light responsive colloidal particles to function as pixels that could be used to create barcodes for cryptographic data storage.

Photochromic dyes are used in films to respond to light, for example in self-dimming sunglasses. These dyes have two isomers, one forms in visible light and is transparent, the other forms in UV light and absorbs light, darkening the sunglasses. If a photochromic dye is placed in a film with a fluorescent dye, and the wavelength of the fluorescence is matched to that absorbed by the photochromic dye, the photochromic dye can be used to switch the fluorescence off and on when exposed to UV or visible light.

Clemens Weiß and his colleagues at the Max-Planck Institute for Polymer Research in Germany, have devised a way to use this kind of light triggered dye switch to store data. Encapsulating the photochromic/fluorescent dye pair inside polymer colloids traps the molecules together prolonging the lifetime of the ‘on’ or ‘off’ state for several days. Assembling these functional colloids within a monolayer of larger colloids creates a grid of fluorescent ‘colloidal pixels’. Shining UV light on chosen areas of the grid turns the pixels’ fluorescence off creating dark areas on the grid whilst leaving others fluorescent.

Interested to know more? Read the full news article by Emily Skinner in Chemistry World here…

Read the article by K. Bley, N. Sinatra, N. Vogel, K. Landfester and C. K. Weiss in Nanoscale:

Switching light with light – advanced functional colloidal monolayers
K. Bley, N. Sinatra, N. Vogel, K. Landfester and C. K. Weiss
DOI: 10.1039/C3NR04897G, Paper

Graphene could find use in next-generation flexible electronic devices thanks to scientists in Taiwan and the US who have developed a low cost and scalable method to pattern graphene onto 3D surfaces.

Flexible electronics are destined to transform the way we manufacture and interact with electronic devices. Graphene’s high electrical conductivity and mechanical stability could prove beneficial in flexible electronic circuits. However, despite its potential, graphene is typically only produced and patterned in research environments with economic barriers hampering its use in commercial applications.

Now, a group led by Mario Hofmann at National Cheng Kung University have demonstrated an easy and scalable approach to depositing high resolution graphene patterns onto surfaces.

Interested to know more? Read the full news article by Michael Parkin in Chemistry World here…

Read the article by Mario Hofmann, Ya-Ping Hsieh, Allen L. Hsu and Jing Kong in Nanoscale:

Scalable, flexible and high resolution patterning of CVD graphene
Mario Hofmann, Ya-Ping Hsieh, Allen L. Hsu and Jing Kong
DOI: 10.1039/C3NR04968J

When probing or building structures at the nanoscale, experimental readings are so tiny that they are easily drowned out by any background noise – without a well-proofed lab, someone using the lift next door could ruin your results.

Interested to know more? Read the full news article by Rowan Frame in Chemistry World here…

The labs were designed to screen all sources of background noise relevant to nanotechnology

Read the article by  E Lörtscher, D Widmer and B Gotsmann in Nanoscale:

Next-Generation Nanotechnology Laboratories with Simultaneous Reduction of all Relevant Disturbances
Emanuel Lörtscher, Daniel Widmer and Bernd Gotsmann  
DOI: 10.1039/C3NR03373B