Archive for the ‘Materials’ Category

Meet our author… Greg Qiao

Greg Qiao is a polymer scientist and engineer at the University of Melbourne in Australia. His research interests cover various polymerisation techniques, including controlled free radical polymerisations, in a bid to synthesise novel polymeric architectures, biodegradable and functional polymers.  

Qiao’s recent communication, published in ChemComm, touches upon his interest in using polymers as coatings for the automotive industry or as potential drug delivery vehicles: ‘Star Polymers Composed Entirely of Amino Acid Building Blocks: A Route towards Stereospecific, Biodegradable and Hierarchically Functionalized Stars 

Below, Greg takes some time away from his research to talk to us… 

What initially inspired you to become a scientist?
When I was a child, I always dreamed of becoming a scientist. I chose science and engineering as my major when starting university and fell in love with both chemistry and chemical engineering.  I’ve always believed that science and technology can change and improve life for the human society.

Greg Qiao

What was your motivation behind the work described in your ChemComm article?
My research group has spent over 10 years in the field of controlled synthesis and characterisation of core crosslinked star (CCS) polymers. We initially used controlled free radical polymerisation methods, including nitroxide–mediated polymerisation (NMP) and atom transfer radical polymerisation (ATRP) methods, to synthesise CCS polymers and study their properties including molecular morphology and solution rheology. We also studied CCS analogues for their suitability as additive to automotive paint.
 
Five years ago, we started to synthesise CCS polymers with alternative polymerisation methods including ring opening polymerisation (ROP) for selectively degradable CCS. More recently, we have been working on new ways to form CCS which is fully biodegradable and biocompatible.  In this work, we developed a new process by using peptide synthesis as a controlled chain growth method to produce CCS. This process not only uses entirely naturally occurred amino-acid precursors, but also provides more convenient approaches to functionalise CCS at its core, along the arms and at the end of the arms. We are hoping this work can lay foundation for the new peptide-based drug delivery vehicles.

 

Why did you choose ChemComm to publish your work?
Because of the fast and broad readership, as well as its high impact.
 
Where do you see your research heading next?
We wish to develop this unique peptide-based CCS as a drug carrier for delivering drugs to targeted cells. My other research direction is using the controlled polymerisation method to create an efficient and thickness-controlled surface coating technology. 
 
What do enjoy doing in your spare time?
Reading a good article that has a completely fresh, new idea.
 
If you could not be a scientist, but could be anything else, what would you be?
Politician or publican servant – something to serve the public.

Other polymer articles recently published  in ChemComm that might also interest you include:-

Emerging synthetic approaches for protein–polymer conjugations
Rebecca M. Broyer, Gregory N. Grover and Heather D. Maynard
Chem. Commun., 2011, 47, 2212-2226
DOI: 10.1039/C0CC04062B, Feature Article

 Functional, star polymeric molecular carriers, built from biodegradable microgel/nanogel cores
Jay A. Syrett, David M. Haddleton, Michael R. Whittaker, Thomas P. Davis and Cyrille Boyer
Chem. Commun., 2011, 47, 1449-1451
DOI: 10.1039/C0CC04532B, Communication

A synthetic approach to a fullerene-rich dendron and its linear polymer via ring-opening metathesis polymerization
Jonggi Kim, Myoung Hee Yun, Junghoon Lee, Jin Young Kim, Fred Wudl and Changduk Yang
Chem. Commun., 2011, Advance Article
DOI: 10.1039/C0CC05470D, Communication

Cationic and charge-neutral calcium tetrahydroborate complexes and their use in the controlled ring-opening polymerisation of rac-lactide
Michael G. Cushion and Philip Mountford
Chem. Commun., 2011, 47, 2276-2278
DOI: 10.1039/C0CC04348F, Communication
 

And also from our sister journal Chemical Science, a Perspective and an Edge Article for you to read:-

 Triggered structural and property changes in polymeric nanomaterials
Jason M. Spruell and Craig J. Hawker
Chem. Sci., 2011, 2, 18-26
 

Cylindrical micelles from the living crystallization-driven self-assembly of poly(lactide)-containing block copolymers
Nikos Petzetakis, Andrew P. Dove and Rachel K. O’Reilly
Chem. Sci., 2011, Advance Article
 
 

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Confining supramolecular soft materials

Confining soft materials in a small space has a dramatic effect on the formation of fibre networks and their resulting properties. 

 
 

Optical micrographs of the gels studied

Xiang Yang Liu and collaborators showed that the formation of fibre networks under volume confinement is independent of temperature and solute concentration. They need to do more studies to understand the mechanism but say that their work should help scientists design new soft functional materials on a micro-/nanometre scale.

Fancy delving some more into the results reported? Then why not download the communication* today and leave some comments on the blog below. Perhaps you have a question for the authors, or you could tell us what you found interesting about these results.

 *This communication will be free to access until the 25th March 2011.

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Nanoflowers for protein immobilisation and separation

It is the quest of many a materials scientist to form core-shell nanostructures by self-assembly, in order to generate materials with unique structures and functions. In this area, hierarchical nanoarchitectures assembled from nanoscale units have recently stimulated tremendous interest because these superstructures might avoid aggregation and maintain high specific surface areas. In addition, magnetic materials have received considerable interest,  due to their ability to selectively capture target objects from complex mixtures.

Ken Cham-Fai Leung and colleagues – based in Hong Kong and Hefei, China – have reported a facile synthesis of monodispersed microparticles composed of superparamagnetic Fe3O4 cores, a SiO2 shell and a hierarchical g-AlOOH periphery with Au nanoparticles, obtaining nanoflower structures resembling daisies. As proof of principle for their use as selective protein capturing agents, these nanoflowers were applied as absorbents to successfully remove bovine serum albumin from bovine blood.

To find out more download the ChemComm communication, which is free to access until 15th March 2011.

Start a discussion about this research by leaving comments below.

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MOF magnets deliver drugs

German scientists have encapsulated nanomagnets inside metal organic frameworks (MOFs). The MOF magnets can be filled with a drug, which is released when a magnetic field is applied. 

Stefan Kaskel from the Technical University of Dresden and colleagues made the MOF magnets by integrating superparamagnetic iron oxide particles into carboxylate MOFs. ‘Carboxylate molecules stabilise and activate the nanoparticles,’ explains team member Martin Lohe.

The group then loaded their MOF with ibuprofen and found that they were able to trigger and control its release by simply applying an external magnetic field. The magnetic field heats the magnets in the MOF, which causes the load to burst from the framework.

Superparamagnetic functionalisation of MOFs enables magnetic heating to trigger drug delivery

MOFs in which the frameworks themselves are magnetic have been made before, but they are not easy to manipulate. Kaskel’s embedded MOF magnets, however, can easily be manipulated from the outside. Magnetic fields can penetrate human skin, and magnetic triggers that could be used to release the drugs are already available on the market. However, before the MOF magnets can be used in the human body, toxicity tests will need to be done.

‘An enhanced sustainability of industrial and medical processes is crucial for our future,’ says Lohe. ‘Magnetically functionalised MOFs could be a small building block on this path.’

‘The particles will certainly increase the possibility of using nanoMOFs for drug delivery applications in the near future,’ agrees Christian Serre, an expert in porous solids from the University of Versailles  in France, ‘and they’ll add a new tool to the emerging domain of MOFs in biomedicine.’ 

Ruth Doherty

 

Link to ChemComm article

 Heating and separation using nanomagnet-functionalized metal–organic frameworks
Martin R. Lohe, Kristina Gedrich, Thomas Freudenberg, Emanuel Kockrick, Til Dellmann and Stefan Kaskel,

Chem. Commun., 2011, DOI: 10.1039/c0cc05278g

 

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New polymer hydrogels offer step forward in desalination

Chemists working in Australia have used polymer hydrogels as a ‘draw’ agent in a desalination process.

Forward osmosis (FO) desalination is an emerging area of interest for chemists as it provides a low energy method of obtaining salt free water from the sea. Typically in FO, saline water is separated by a membrane from a ‘draw’ solute. Water passes through the membrane from the saline side to the ‘draw’ solute via osmosis. The water is then recovered from the ‘draw’ agent using distillation.

Now Huanting Wang and colleagues at Monash University have investigated the use of polymer hydrogels as the draw agent for FO desalination. Polymer hydrogels can reversibly change their volume when exposed to certain stimuli such as temperature and pressure. This gives them an advantage over traditional draw agents as they can potentially be recycled and release the water at lower energy and therefore cost.

Graphical abstract: Stimuli-responsive polymer hydrogels as a new class of draw agent for forward osmosis desalination

The team found that it is indeed possible to release significant amounts of water from the polymer hydrogels tested and are investigating other stimuli, such as light, to further increase the efficiency of this process.

Read more about this exciting advance by downloading  the full ChemComm communication today and let us know what you think below.

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