Synthetically created melanin can be used as a toxin adsorbent when applied to fabric. New material protected fabric from nerve gas penetration. Examples in nature lead researchers to believe these materials ‘exist out there’.
When Nathan Gianneschi’s lab set out to synthesize melanin that would mimic that which was formed by certain fungi known to inhabit unusual, hostile environments including spaceships, dishwashers and even Chernobyl, they did not initially expect the materials would prove highly porous — a property that enables the material to store and capture molecules.
Melanin has been found across living organisms, on our skin and the backs of our eyes, and as pigments for many animals and plants. It also plays a role in protecting species from environmental stressors. Turtle-headed sea snakes’ stripes darken, for example, in the presence of polluted water; moths living in industrial areas turn black as their cells absorb toxins in soot. The researchers wondered whether this type of biomaterial could be made more sponge-like, to optimize these properties. And, in turn, whether sponge-like melanins existed already in nature.
«Melanin’s function isn’t fully known all the time and in all cases,» Gianneschi, the corresponding author on the study, said. «It’s certainly a radical scavenger in human skin and protects against UV damage. Now, through synthesis we’ve happened upon this exciting material that very well may exist in nature. Fungi might make this material to add mechanical strength to their cells, but is porous, allowing nutrients across.»
The study will be published Friday, March 5, in the Journal of the American Chemical Society.
Gianneschi is the Jacob and Rosaline Cohn Professor of Chemistry in the Weinberg College of Arts and Sciences. With appointments in the materials science and biomedical engineering departments in the McCormick School of Engineering, Gianneschi also is associate director of the International Institute for Nanotechnology.
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Materials provided by Northwestern University. Original written by Lila Reynolds. Note: Content may be edited for style and length.