NEWS OF THE WEEK
SECRET OF WHITE BEETLE REVEALED BIOMATERIALS: Insect's
bright white scales are due to randomly oriented fibers
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HAT MAKES A WHITE BEETLE so bright
white? A new study shows that the brilliance originates from a network of 250-nm-thick fibers found in the interior of the beetle's scales. The investigation provides an explanation for one of nature's curiosities and may suggest new ways of making bright white ultrathin structures for display applications. Vivid colors and dazzling patterns are commonplace among species in the animal kingdom. But animals featuring luminescent white coloring are uncommon. Cyphochilus, a beetle found in Thailand and elsewhere in Southeast Asia, is an unusually white critter. Experts propose that the whiteness of the beetle's thin scales, which cover its body, head, and legs, aids the bug in mimicking local white fungi and serves as a form of camouflage. The origin of that whiteness and the beetle's secret for deriving so much brightness from its scales, which are thinner than synthetic bright white products, have now been revealed. On the basis of electron microscopy analysis, researchers in England report that the beetle's scales, which typically are 250 um long, 100 urn wide, and just 5 Jim thick, are composed of a tangle of randomly oriented interconnecting cuticle-like fibers 250 nm thick. According to the research group, which includes physicists Pete Vukusic and Joseph Noyes of the University of Exeter and Benny Hallam of Imerys Minerals, in Cornwall, the lack of order and periodicity in the fiber network and the fibers' sparse packing arrangement
and large contrast in refractive index relative to air are the sources of the beetle's bright white appearance (Science 2007, Unlike the hues of colorful animal wings and other objects, which often owe their striking appearance to pigments or periodic structural order, whiteness is usually the result of random structure and lack of order. Vukusic explains that, similar to the aperiodic structures characteristic of the components of snow and milk, the irregularly spaced fibers in the beetle scales efficiently scatter all wavelengths of incident light, which causes the scales to appear very white. Considering that they are only 5 Jim thick, the beetle scales are remarkably bright white, the team stresses. To quantify that claim, the group used industry-standard whiteness rating methods and found that common uncoated paper samples, which contain disordered bleached cellulose fibers, are only 8% brighter than the beetle scales—yet they are often more than 25 times thicker. (Paper brightness is often boosted by applying coatings of crystalline materials and fluorescent dyes.) The scattering efficiency of the fiber network might one day lead to applications in display technologies— for example, as ultrathin, flexible backing layers for white light-emitting devices. "Nature has demonstrated that structures can be extremely thin and yet very bright," Vukusic says. "It's up to us to take these ideas and figure out where to apply them."-MITCHJACOBY
White beetles owe their bright appearance to a network of fibers that comprise the scales that cover their bodies.
MANUFACTURING Lilly restructures insulin and chemicals operations Eli Lilly & Co. says it will halt construction of a $325 million insulin plant in Prince William County, Va., and that it will scale back its active pharmaceutical ingredient (API) operation at its Tippecanoe site in Lafayette, Ind. Lilly says it will meet expected growth in insulin demand with existing plants and a new site being built in Sesto, Italy. The firm cited excess small-molecule drug capacity in announcing its plan to eliminate up to 250 of the 1,000 jobs in Lafayette. Lilly estimates combined restructuring and asset impairment charges of up to $185 million.
According to a company spokesman, Lilly conceived the new insulin facility in 2003. The company's demand forecast changed, he says, based on the advent of new forms of insulin, notably inhalable products. Lilly has an inhalable insulin in Phase III clinical trials. The insulin plant was to be an important part of a small biotech hub anchored by the life sciences campus of George Mason University, according to Jason Grant, a spokesman for the Prince William County Department of Economic Development. "It's a setback," he says. "Lilly had provided us the international
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JANUARY 22, 2007
name recognition of a publicly traded company." The plant, when completed in 2009, would have created 350 jobs. The 120 current employees will be offered a severance package if they choose not to relocate with the company. Lilly also announced that it will expand its Kinsale, Ireland, biopharmaceutical plant and its Indianapolis parenteral operation, which formulates APIs manufactured in Kinsale. These investments are part of a previously announced $1.5 billion campaign to boost biotechnology capabilities.-RICKMULLIN
