| Mar 23, 2022 |
Feeding silkworms carbon dots to produce brightly fluorescent silk
(Nanowerk News) Silk fibers produced by Bombyx mori, the domestic silkworm, have been prized for millennia as a strong yet lightweight and luxurious material. Although synthetic polymers like nylon and polyester are less costly, they do not compare to silk's natural qualities and mechanical properties.
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More recently, these natural protein fibers have found application as a high technology material in biomedical micro- and nanotechnology. Researchers have even demonstrated the production of mechanically enhanced silk fibers that are twice as strong with silk worm diets containing single-walled carbon nanotubes (SWNTs) or graphene.
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Although the natural Bombyx mori silk has almost no fluorescence, researchers have now managed to get silkworms to produce brightly fluorescent silk.
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They reported their findings in Advanced Materials ("Mulberry-Leaves-Derived Red-Emissive Carbon Dots for Feeding Silkworms to Produce Brightly Fluorescent Silk").
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| a) Photographs of a silkworm in the test group: i) the whole body under green light, ii) the head, and iii) the chest under an automatic stereo fluorescence microscope (filtering out the green excitation light). b) The silkworms in the control group under UV light. (Reprinted with permission by Wiley-VCH Verlag)
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The scientists fed near-infrared-emissive carbon dots made from mulberry leaves to silkworms to produce brightly luminescent natural silk.
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The as-prepared carbon dots have a main emission peak at 676 nm with a shoulder at 725 nm, possessing an full width at half maximum of 20 nm and quantum yield of 73%. According to the team, they are the brightest deep-red-emissive carbon dots so far.
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After being fed the carbon dots for a period of time, the silkworm bodies, alimentary canals, silk glands, feces, cocoons, eggs and moths became a red fluorescent with the spectral features of deep-red-emissive carbon dots. Therefore, the physiological activities of the test silkworms can be monitored by fluorescence imaging, even be seen by naked eyes.
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Since the carbon dots could be metabolized and partially transferred into silk glands, the resulting silk fiber also became brightly luminescent.
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Since such deep-red-emissive carbon dots can be easily prepared from mulberry leaves on large scale and the fed silkworms have a survival rate of nearly 100%, the fluorescent Bombyx mori silk will have a mass production for practical applications in the future.
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By
Michael
Berger
– Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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