Robert L. Mauck and Brendon M. Baker, University of Pennsylvania (US), have developed and validated a new technology in which composite nanofibrous scaffolds provide a loose enough structure for cells to colonize without impediment, but still can instruct cells how to lay down new tissue. "These are tiny fibers with a huge potential that can be unlocked by including a temporary, space-holding element," says Mauck. The fibers are on the order of nanometers in diameter.

Image: Dynamic transition in a fibrous biomaterial composed of tunable fractions of structural (red) and water-soluble, sacrificial (green) electrospun polymeric nanofibers. The image was captured as fluid entered from right to left, dissolving sacrificial fibers and creating a more open fibrous network. © Brendon M. Baker, PhD; Perelman School of Medicine, University of Pennsylvania

Brendon M. Baker, Roshan P. Shah, Amy M. Silverstein, John L. Esterhai, Jason A. Burdick, and Robert L. Mauck: Sacrificial nanofibrous composites provide instruction without impediment and enable functional tissue formation, In: PNAS Early Edition, August 7, 2012, DOI:10.1073/ pnas.1206962109:

http://dx.doi.org/10.1073/pnas.1206962109 http://www.med.upenn.edu/

In rivers and other bodies of water, sunlight can help dissolved organic matter reduce silver and gold ions to form nanoparticles of the metals, according to researchers in China at State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences.

Yongguang Yin, Jingfu Liu, and Guibin Jiang: Sunlight-Induced Reduction of Ionic Ag and Au to Metallic Nanoparticles by Dissolved Organic Matter, In: ACS Nano ASAP, July 22, 2012, DOI:10.1021/nn302293r: http://dx.doi.org/10.1021/nn302293r