A 2,000-year-old marine textile known for its luminous gold appearance has been reproduced from a pen shell species farmed in Korean coastal waters. The recreated fibre derives its colour from ordered protein layers that bend and reflect light at the nanoscale. The researchers showed that the material’s colour stability results from internal structural alignment rather than applied pigment, explaining its resistance to fading across centuries.
- By processing byssus threads from Atrina pectinata, a pen shell species cultivated in Korean coastal waters, researchers recreated a fibre with physical and chemical properties closely matching traditional sea silk.
- The golden sheen results from structural coloration, where layered photonin proteins generate iridescence through light interaction rather than applied pigments.
- The study was published recently in Advanced Materials and detailed how protein alignment determines colour intensity and long-term resistance to fading.
THE STUDY: Researchers at POSTECH in South Korea reproduced ancient sea silk using byssus threads from Atrina pectinata, a pen shell species cultivated in Korean coastal waters for food. The work was led by Professor Dong Soo Hwang and Professor Jimin Choi and focused on identifying a viable alternative to Pinna nobilis, the Mediterranean clam historically used to produce the rare textile, whose decline had pushed traditional sea silk production into near disappearance.
- The team confirmed that byssus from Atrina pectinata closely matches the physical and chemical properties of traditional sea silk fibres.
- They developed a processing method to transform pen shell threads into a textile resembling the luminous golden material described in historical records.
- Pinna nobilis populations have declined sharply due to marine pollution and environmental damage, leading the European Union to ban harvesting of the species.
- The paper, titled ‘Structurally Colored Sustainable Sea Silk from Atrina pectinata’, was authored by Jimin Choi, Jun‐Hyung Im, Young‐Ki Kim, Tae Joo Shin, Patrick Flammang, Gi‐Ra Yi, David J. Pine and Dong Soo Hwang.
INSIDE THE STRUCTURE: Sea silk’s enduring golden appearance arises from structural coloration rather than applied dyes or metallic treatments. The fibre’s colour is generated when light interacts with nanoscale protein formations embedded within the material. The researchers showed that the degree of protein ordering directly influences colour intensity, explaining the fibre’s long-term resistance to fading.
- Researchers identified a spherical protein structure known as photonin as central to the fibre’s iridescent effect, linking nanoscale architecture to the generation of stable visible colour.
- These proteins assemble into layered arrangements that reflect light in ways comparable to soap bubbles or butterfly wings, producing optical effects through structural configuration rather than chemical pigmentation.
- The study showed that colour intensity increases as protein layers become more precisely ordered within the fibre.
- Because the hue originates from internal structure rather than external application, the material resists fading over long periods of time.
FROM HISTORY TO SUSTAINABILITY: The recreation of sea silk addresses both material scarcity and environmental constraints that nearly ended the craft. Declining populations of Pinna nobilis and a European Union ban on harvesting pushed the historic fibre into near disappearance. By using Atrina pectinata, a species farmed for food, the research demonstrates an alternative pathway that reconnects cultural heritage with contemporary material science.
- Sea silk was once reserved for emperors and popes, and is associated with artefacts such as the Holy Face of Manoppello, a centuries-old religious relic in Italy believed to be made from the material.
- Marine pollution and habitat damage severely reduced Pinna nobilis populations, turning sea silk production into a marginal artisanal practice.
- Byssus threads from farmed pen shells were previously discarded as waste, limiting their economic value.
- Converting these threads into textile fibre reduces marine waste while enabling dye-free colour production without metals.
- The approach links sustainable material development with historical textile knowledge rather than relying on synthetic substitutes.
WHAT THEY SAID
Structurally colored textiles are inherently resistant to fading. Our technology enables long-lasting color without the use of dyes or metals, opening new possibilities for sustainable fashion and advanced materials.
— Dong Soo Hwang
Professor
POSTECH
