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Multivascular networks and functional intravascular topologies within biocompatible hydrogels

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Science  03 May 2019:
Vol. 364, Issue 6439, pp. 458-464
DOI: 10.1126/science.aav9750

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  • RE: Appropriate credit to previously published, uncited work: “Light-based 3D printing of hydrogels with high-resolution channels”, Benjamin et al., Biomed. Phys. Eng. Express, 5, 025035 (2019) doi: 10.1088/2057-1976/aad667.
    • James Nolen Wilking, Assistant Professor of Chemical and Biological Engineering, Montana State University

    The paper by B. Grigoryan et al. in Science, 364, 458-464 (2019) is a beautiful and comprehensive body of work that advances light-based 3D printing of hydrogels for biological applications. However, in contrast to what the authors claim, this is not the first reported use of a biocompatible food dye as a photoblocker for creating transparent hydrogels using light-based 3D printing. Their paper does not acknowledge our previously-published work “Light-based 3D printing of hydrogels with high-resolution channels” (Benjamin et al., Biomed. Phys. Eng. Express, 5, 025035 (2019) doi: 10.1088/2057-1976/aad667), which describes the use of yellow food dye (tartrazine) for use as a photoblocker for achieving high-resolution channels in PEG-based, transparent hydrogels with light-based 3D printing.

    In our paper, we present a generalizable method for light-based 3D printing of hydrogels containing well-defined, submillimeter-scale channels with any orientation. To do this, we used both tartrazine and chlorophyllin as photoblockers. Importantly, we state in our paper, “Tartrazine is a yellow azo dye commonly found in food coloring, with strong absorbance at 405 nm. To our knowledge, this is the first reported use of both these compounds as photoblockers.” Moreover, we also state, “tartrazine does not bind to the gel; instead, when the hydrogel is placed in water, tartrazine diffuses out of the gel into the water. Thus, tartrazine provides an alternative photoblocker for creati...

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    Competing Interests: None declared.