The narwhal tusk assembles its macroscopic helix from building blocks with opposing twists
Year: 2026
Type: article
Abstract: Narwhal tusks are among the most intriguing structures in biology due to their immense size and unique left-handed helix. Whether this unique macroscopic homochirality originates in the structural arrangement of tusk building blocks has remained elusive. Therefore, we combined multiple structural techniques to reveal the hierarchical structure of the narwhal tusk from its building blocks (mineralized collagen fibrils) up to the macroscopic left-hand helix. Thus, we show that the macroscopic helical structure is reproduced from the molecular-scale arrangement of mineralized collagen in a double helix with opposite chirality. While mineralized collagen predominantly aligns along the tusk long axis, systematic axial deviations build helical arrangements of fibrils. Cementum has a left-hand helix of collagen fibrils, while dentine contains a right-hand arrangement extending across annual growth layers that feature distinct biomineral properties. This discovery advances understanding of how biological tissues integrate multiscale structural patterns to achieve specific mechanical and biological functions.
Source: Nature Communications
Authors: Adrian Rodriguez-Palomo, Peter Alling Strange Vibe, Dimitra Athanasiadou, Jonas Palle, Leonard C. Nielsen, Jonathan T. Avaro, Thorbjørn Erik Køppen Christensen, Nina Kølln Wittig, Mads Ry Vogel Jørgensen, Innokenty Kantor, Manfred Burghammer, Jiliang Liu, Stefano Checchia, Christian Appel, Karl Anker Jørgensen, Eva Garde, Mads Peter Heide-Jørgensen, Marianne Liebi, Henrik Birkedal
Institutions: Aarhus University, Chalmers University of Technology, Swiss Federal Laboratories for Materials Science and Technology, Lund University, Sino-Danish Centre for Education and Research, MAX IV Laboratory, University of Chinese Academy of Sciences, Technical University of Denmark, European Synchrotron Radiation Facility, Paul Scherrer Institute, Grønlands Naturinstitut, École Polytechnique Fédérale de Lausanne
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,990
OpenAlex ID: W7203687469