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quinta-feira, 10 de novembro de 2011

Leading armies of nanoparticles to supercapacity



JOB: Physical Chemist
Location: Brisbane, Queensland
Institution: Australian Institute for Bioengineering and Nanotechnology, University of Queensland

Jian Liu
Credit: Jian Liu

WHEN IT COMES TO GLOBAL, consumer-friendly developments in iPhone batteries and drug delivery to cancer cells, physical chemist Jian Liu proves that particle research is no small matter. 
Liu is knee-deep in some of the most cutting-edge and applicable research today: safer and more effective drug delivery and longer-lasting batteries for your iPhone or laptop. Add an award for excellence in research from the University of Queensland of A$80,000 on top of that, and you have a recipe for scientific success.
A physical chemist at the Australian Institute for Bioengineering and Nanotechnology at the University of Queensland (UQ), Liu will help improve carbon nanostructured electrode materials - a big term that coins tiny electrically-conducting packages of carbon ranging from microscopic to molecular in size - with his monetary prize.
Liu and his team have already synthesised materials that are nanoporous - which means supporting a porous surface - in the lab. By controlling particle size, pore size and changing the form and structure of the nanomaterials, the research has taken sizable steps in advancing gene therapy and drug delivery.
In 2009, Liu obtained his PhD in physical chemistry from the Chinese Academy of Science and joined the team at UQ as a research fellow upon invitation. Since then, his research has focussed on the applications of yolk/shell nanomaterials in particular.
A new particle is hatched
Yolk/shell or 'rattle-typed' carbon nanomaterials are tiny particles of a hollow shell encasing a nanoparticle core, and are named after an egg with a shell, interstitial space and the core - the yolk. Liu and his team have developed a more porous shell, which makes the yolk/shell structure used in medical settings for drug delivery safer and more efficient. The breathable nanomaterial has a huge surface area for its tiny size, and is small enough to enter cells for gene therapy, said Liu.
In addition, the drug will be controlled-release from the nanomaterial, which makes sense since the breathable pores restrict the drug to seep into the cell and not flow. The more control needed for the dispersion of a drug into a cell, the more hierarchical microporous and mesoporous layers inside the shell that can be created for slower dispersion. This will make drugs' effects much safer (think of cracking an egg versus letting the liquid seep out slowly through tiny holes in the shell) on the cell.
"On a practical level, yolk/shell nanoparticles (YSNs) have a number of applications such as catalysis, lithium-ion batteries and biosensors due to their tailorability in both the hollow shell and the core," added Liu.
Charging your batteries
Lowering drug risks is just one benefit of the improved YSN structure. Another potential application of the YSNs is their use as anode materials - used to put electricity into a cell - for lithium-ion batteries. Who hasn't pulled their laptop or iPhone out of its case to find it runs out of charge in a frustratingly short time?
"Consumers are desperate for low-cost, high-energy-density, and long-lasting rechargeable 'Li-ion' batteries," said Liu. Liu tackles the need to increase power density, cycling life, and charge capability by using the YSN model to stop the nanoparticles from attracting and clustering with one another, which lessens energy output, and provide space for the huge volumes of nanoparticles to move freely during charge and discharge, helping to buffer the volume change when charging and recharging and improve battery performance.
"Energy storage is more important today than at any time in human history," said Liu. "By using these nanostructured materials as electrodes, a new generation of supercapacitors to complement or replace batteries in certain applications where high-efficiency, high power, and high level of reliability will be developed."

Fonte: Cosmos