{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T18:45:02Z","timestamp":1788633902220,"version":"build-2803163510"},"reference-count":64,"publisher":"National Academy of Sciences","issue":"12","license":[{"start":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T00:00:00Z","timestamp":1773705600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000781","name":"EC | European Research Council","doi-asserted-by":"publisher","award":["ERC\u20102020\u2010CoS-101001637"],"award-info":[{"award-number":["ERC\u20102020\u2010CoS-101001637"]}],"id":[{"id":"10.13039\/501100000781","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100010661","name":"EC | Horizon 2020 Framework Programme","doi-asserted-by":"publisher","award":["N 860125 \u201cBEEP\u201d"],"award-info":[{"award-number":["N 860125 \u201cBEEP\u201d"]}],"id":[{"id":"10.13039\/100010661","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000654","name":"Marie Curie","doi-asserted-by":"publisher","award":["101155041"],"award-info":[{"award-number":["101155041"]}],"id":[{"id":"10.13039\/501100000654","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2026,3,24]]},"abstract":"<jats:p>\n                    Nudibranchs are well known for their bright and diverse color patterns. This coloration is typically a form of aposematism, warning predators against toxic compounds sequestered from their prey and weaponized as a form of defense. Although many of the hues in nudibranchs were thought to be of pigmentary origin, here we show, using a combination of white light and Raman microspectroscopy, that hierarchically organized micron-scale guanine multilayer structures are responsible for many of these colors. Such architectures are widespread across the dorid and aeolid groups and are responsible for a striking array of angular-independent structural colors. By using cryogenic focused ion beam (cryo-FIB) SEM tomography, we were able to access the complex 3D organization of the guanine nanoplatelets responsible for the strong blue coloration of\n                    <jats:italic toggle=\"yes\">Chromodoris annae<\/jats:italic>\n                    . We propose that the multilayer organization of guanine platelets with varying orientations across the tissue and their micron-scale size offers a particularly effective strategy for producing diverse optical effects. The macroscopic angular independent color results from individual multilayers which we describe as \u201cpixels\u201d, these \u201cpixels\u201d reflect light at a wavelength governed by their interlayer spacing and guanine platelet thickness. The macroscopic hue can be spectrally tuned by altering the statistical distribution of pixels with each color, while the angular dependence of color can be changed through the relative orientation of the multilayer stacks and their size, allowing for a single structural motif to generate a broad palette of optical appearances.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2525419123","type":"journal-article","created":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T18:08:26Z","timestamp":1773770906000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":3,"title":["Nudibranch color diversity shares a common physical basis in guanine photonic structure \u2018pixels\u2019"],"prefix":"10.1073","volume":"123","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3923-0589","authenticated-orcid":false,"given":"Samuel","family":"Humphrey","sequence":"first","affiliation":[{"name":"Department of Sustainable and Bio-inspired Materials, Max Planck Institute of Colloids and Interfaces","place":["Potsdam, Germany"]},{"name":"Bio-inspired Photonics Group, Yusuf Hamied Department of Chemistry, University of Cambridge","place":["Cambridge, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-3781-0664","authenticated-orcid":false,"given":"Xianglian","family":"He","sequence":"additional","affiliation":[{"name":"Department of Sustainable and Bio-inspired Materials, Max Planck Institute of Colloids and Interfaces","place":["Potsdam, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5162-8856","authenticated-orcid":false,"given":"Tobias","family":"Priemel","sequence":"additional","affiliation":[{"name":"Department of Sustainable and Bio-inspired Materials, Max Planck Institute of Colloids and Interfaces","place":["Potsdam, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0724-7084","authenticated-orcid":false,"given":"Vera Marie","family":"Titze","sequence":"additional","affiliation":[{"name":"Department of Sustainable and Bio-inspired Materials, Max Planck Institute of Colloids and Interfaces","place":["Potsdam, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5869-5701","authenticated-orcid":false,"given":"Sinuh\u00e9","family":"Perea-Puente","sequence":"additional","affiliation":[{"name":"Department of Sustainable and Bio-inspired Materials, Max Planck Institute of Colloids and Interfaces","place":["Potsdam, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vivek","family":"Subramanian","sequence":"additional","affiliation":[{"name":"Materials and Structural Analysis, Thermo Fisher Scientific","place":["Hi6llsboro"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cedric","family":"Bouchet-Marquis","sequence":"additional","affiliation":[{"name":"Materials and Structural Analysis, Thermo Fisher Scientific","place":["Hi6llsboro"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bruno","family":"Jesus","sequence":"additional","affiliation":[{"name":"D\u00e9partement Biologie, Institut Des Substances Et Organismes de La Mer, Nantes Universit\u00e9","place":["Nantes, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0664-1418","authenticated-orcid":false,"given":"Silvia","family":"Vignolini","sequence":"additional","affiliation":[{"name":"Department of Sustainable and Bio-inspired Materials, Max Planck Institute of Colloids and Interfaces","place":["Potsdam, Germany"]},{"name":"Bio-inspired Photonics Group, Yusuf Hamied Department of Chemistry, University of Cambridge","place":["Cambridge, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2026,3,17]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1748-1090.1995.tb00659.x"},{"key":"e_1_3_4_2_2","volume-title":"Undersea Jewels: A Colour Guide to Nudibranchs","author":"Cobb G.","year":"2006","unstructured":"G. Cobb, R. C. Willan, Undersea Jewels: A Colour Guide to Nudibranchs (Australian Biological Resources Study, Canberra, 2006)."},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1093\/mollus\/57.Supplement_Part_4.5"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1186\/1742-9994-2-3"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1420-9101.2010.02018.x"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1086\/698012"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1007\/s12526-021-01233-5"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.tet.2007.03.082"},{"key":"e_1_3_4_9_2","first-page":"127","volume-title":"Adaptive Coloration in Invertebrates","author":"Gosliner T. M.","year":"1990","unstructured":"T. M. Gosliner, D. W. Behrens, \u201cSpecial resemblance, aposematic coloration, and mimicry in opisthobranch gastropods\u201d in Adaptive Coloration in Invertebrates, M. Wicksten, Ed. (University Press, Texas A&M, 1990), pp. 127\u2013138."},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1039\/C7NP00041C"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1016\/0305-0491(72)90007-7"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1038\/ncomms7368"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1002\/adfm.201603514"},{"key":"e_1_3_4_14_2","first-page":"285","article-title":"Review lecture: On the organization of reflecting surfaces in some marine animals","volume":"258","author":"Denton E.","year":"1970","unstructured":"E. Denton, Review lecture: On the organization of reflecting surfaces in some marine animals. Lond. B Biol. Sci. 258, 285\u2013313 (1970).","journal-title":"Lond. B Biol. Sci."},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1002\/adfm.200901437"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1088\/1464-4258\/2\/6\/201"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.aam9506"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1021\/acs.chemmater.5b03549"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1021\/acs.cgd.3c01290"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2308531121"},{"key":"e_1_3_4_21_2","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.5b05289"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201502268"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1002\/dvdy.10334"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.1971.0051"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2215193120"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.1186\/s42649-021-00063-w"},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1204383109"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1002\/adma.200903699"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1364\/OE.18.014430"},{"key":"e_1_3_4_30_2","doi-asserted-by":"publisher","DOI":"10.1002\/adfm.202302720"},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevE.83.011908"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1098\/rstb.2007.2258"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.1002\/adom.202000432"},{"key":"e_1_3_4_34_2","doi-asserted-by":"publisher","DOI":"10.1098\/rsfs.2016.0154"},{"key":"e_1_3_4_35_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1511354112"},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1126\/sciadv.1603119"},{"key":"e_1_3_4_37_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.mtadv.2024.100524"},{"key":"e_1_3_4_38_2","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.076869"},{"key":"e_1_3_4_39_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-019-08891-x"},{"key":"e_1_3_4_40_2","doi-asserted-by":"publisher","DOI":"10.1098\/rsif.2008.0366.focus"},{"key":"e_1_3_4_41_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.adn1570"},{"key":"e_1_3_4_42_2","doi-asserted-by":"publisher","DOI":"10.1038\/ncomms7322"},{"key":"e_1_3_4_43_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0749.2006.00360.x"},{"key":"e_1_3_4_44_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature01941"},{"key":"e_1_3_4_45_2","doi-asserted-by":"publisher","DOI":"10.1093\/database\/baaa062"},{"key":"e_1_3_4_46_2","doi-asserted-by":"publisher","DOI":"10.1248\/cpb.57.885"},{"key":"e_1_3_4_47_2","doi-asserted-by":"publisher","DOI":"10.1007\/s10886-018-0941-5"},{"key":"e_1_3_4_48_2","doi-asserted-by":"publisher","DOI":"10.1016\/0041-0101(94)90334-4"},{"key":"e_1_3_4_49_2","doi-asserted-by":"publisher","DOI":"10.1186\/s12983-022-00460-1"},{"key":"e_1_3_4_50_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF00393124"},{"key":"e_1_3_4_51_2","first-page":"658","article-title":"Feeding behavior, ceras structure, and nematocyst storage in the aeolid nudibranch, Spurilla neapolitana","volume":"27","author":"Conklin E. J.","year":"1977","unstructured":"E. J. Conklin, R. N. Mariscal, Feeding behavior, ceras structure, and nematocyst storage in the aeolid nudibranch, Spurilla neapolitana. Bull. Mar. Sci. 27, 658\u2013667 (1977).","journal-title":"Bull. Mar. Sci."},{"key":"e_1_3_4_52_2","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.2024.0953"},{"key":"e_1_3_4_53_2","doi-asserted-by":"publisher","DOI":"10.1021\/acsphotonics.9b00173"},{"key":"e_1_3_4_54_2","first-page":"181","volume-title":"Bright Earth: Art and the Invention of Color","author":"Ball P.","year":"2002","unstructured":"P. Ball, Bright Earth: Art and the Invention of Color (Farrar, Straus & Giroux, New York, 2002), pp. 181\u2013191."},{"key":"e_1_3_4_55_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1210105109"},{"key":"e_1_3_4_56_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41396-022-01264-1"},{"key":"e_1_3_4_57_2","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.2c00724"},{"key":"e_1_3_4_58_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jsb.2019.04.009"},{"key":"e_1_3_4_59_2","first-page":"11","article-title":"A high-power interference microscope","volume":"125","author":"Huxley A. F.","year":"1954","unstructured":"A. F. Huxley, A high-power interference microscope. J. Physiol. 125, 11\u20133P (1954).","journal-title":"J. Physiol."},{"key":"e_1_3_4_60_2","doi-asserted-by":"publisher","DOI":"10.1002\/cphc.200500007"},{"key":"e_1_3_4_61_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cpc.2021.108256"},{"key":"e_1_3_4_62_2","doi-asserted-by":"publisher","DOI":"10.1002\/adma.202202242"},{"key":"e_1_3_4_63_2","doi-asserted-by":"publisher","DOI":"10.1002\/dvdy.20513"},{"key":"e_1_3_4_64_2","doi-asserted-by":"crossref","unstructured":"S. Humphrey Data for \u201cNudibranch color diversity shares a common physical basis in guanine photonic structure \u2018pixels\u2019.\u201d https:\/\/doi.org\/10.17617\/3.CDDKLB.Edmond. Deposited 19 January 2026.","DOI":"10.1101\/2025.09.06.674434"}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.2525419123","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T18:08:30Z","timestamp":1773770910000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/10.1073\/pnas.2525419123"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,17]]},"references-count":64,"journal-issue":{"issue":"12","published-print":{"date-parts":[[2026,3,24]]}},"alternative-id":["10.1073\/pnas.2525419123"],"URL":"https:\/\/doi.org\/10.1073\/pnas.2525419123","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,17]]},"assertion":[{"value":"2025-09-12","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-02-06","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-03-17","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e2525419123"}}