The Non-Classical Crystallization Mechanism of a Composite Biogenic Guanine Crystal

Avital Wagner, Vladimir Ezersky, Raquel Maria, Alexander Upcher, Tali Lemcoff, Eliahu D. Aflalo, Yael Lubin, Benjamin A. Palmer

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Spectacular colors and visual phenomena in animals are produced by light interference from highly reflective guanine crystals. Little is known about how organisms regulate crystal morphology to tune the optics of these systems. By following guanine crystal formation in developing spiders, a crystallization mechanism is elucidated. Guanine crystallization is a “non-classical,” multistep process involving a progressive ordering of states. Crystallization begins with nucleation of partially ordered nanogranules from a disordered precursor phase. Growth proceeds by orientated attachment of the nanogranules into platelets which coalesce into single crystals, via progressive relaxation of structural defects. Despite their prismatic morphology, the platelet texture is retained in the final crystals, which are composites of crystal lamellae and interlamellar sheets. Interactions between the macromolecular sheets and the planar face of guanine appear to direct nucleation, favoring platelet formation. These findings provide insights on how organisms control the morphology and optical properties of molecular crystals.

Original languageEnglish
Article number2202242
JournalAdvanced Materials
Issue number31
StatePublished - 1 Aug 2022


  • biogenic crystals
  • composites
  • defects
  • guanine
  • non-classical crystallization

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • General Materials Science


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