Press releases
Please quote Nature Materials as the source of these items.
September 2006
Drug and gene therapies get synchronized
Cancer can be tackled with a combination of drug and genetic therapies, such that the effectiveness of the individual treatments are enhanced, as shown by Yi-yan Yang and colleagues in the October issue of Nature Materials. Beyond the promise for a more effective cure, achieving this synergistic effect also means that the dosage of anticancer treatments could be reduced.
The authors used biodegradable nanoparticles made from a polymer that has both a water-loving side and an oil-loving side. When placed in a water solution the polymer spontaneously forms nanoparticles in which the oil-loving part hides in the core and the water-loving part lines the outside shell. If an oil-loving drug is present in the solution, it will be incorporated in the core. In contrast, the shell can be used to bind DNA or RNA.
The researchers loaded the nanoparticles with a potent anticancer drug and therapeutic gene, and injected them in mouse tumours, and observed a significantly slower growth rate in the tumour.
Co-delivery of drugs and DNA from cationic core–shell nanoparticles self-assembled from a biodegradable copolymer pp791-796
Yong Wang, Shujun Gao, Wen-hui Ye, Ho Sup Yoon and Yi-yan Yang
Published online: 24 September 2006 | doi 10.1038/nmat1737
Why are blue light-emitting diodes so bright?
In the October issue of Nature Materials, a team of researchers propose a solution to the puzzle of why blue light-emitting diodes (LEDs) are so bright. Despite their huge commercial success, until now the reason for this unusual brightness has not been known. The material they are made from, indium gallium nitride, can only be fabricated to such a poor quality that it would not normally be expected to emit much light.
Shigefusa Chichibu and colleagues have ingeniously used positron annihilation spectroscopy to show that the blue light emission originates from structures that consist of only a few atoms, which is what made them so difficult to observe in experiments. The authors propose that their results agree with an older model of structures formed from just three indium atoms in a chain, alternating with nitrogen, that is, In-N-In-N-In. In future, such tiny atomic arrangements might be created on purpose to achieve highly efficient light emission in other materials as well. Shuji Nakamura, one of the authors of this paper, first developed blue LEDs from nitride materials in 1993. For this achievement, he will receive Finland's Millennium Technology Prize on 8 September.
Origin of defect-insensitive emission probability in In-containing (Al,In,Ga)N alloy semiconductors pp810-816
Shigefusa F. Chichibu, Akira Uedono, Takeyoshi Onuma, Benjamin A. Haskell, Arpan Chakraborty, Takahiro Koyama, Paul T. Fini, Stacia Keller, Steven P. Denbaars, James S. Speck, Umesh K. Mishra, Shuji Nakamura, Shigeo Yamaguchi, Satoshi Kamiyama, Hiroshi Amano, Isamu Akasaki, Jung Han and Takayuki Sota
Published online: 3 September 2006 | doi 10.1038/nmat1726
Molecules as ID tags
A polymer with an electronic performance equivalent to that of amorphous silicon has been developed, as reported in the April issue of Nature Materials. The work, carried out by a team of industrial and academic researchers in the UK and the US, demonstrates that printed polymeric materials have finally achieved the speed and performance that will enable them to match that of current transistors.
In the new polymer material, individual molecules align with each other more effectively than ever before. The result is an electronic performance six times better than previously reported. This, coupled with good stability in air, makes such polymers ideal candidates to replace more traditional materials such as amorphous silicon, providing cheap and easy routes to future products.
Electronics made from polymers offer the potential for flexible, low-cost circuits for everyday products. This is possible because the polymers can be processed using simple printing techniques.
