Year: 2022
Type: preprint
Abstract: The hardest and toughest tissues formed by living organisms are organic-mineral composites termed biominerals 1,2. When they are crystalline, their mesostructure includes the nano- and micro-scale crystallite size, shape, arrangement, and orientation. Mesostructures vary enormously across marine CaCO3 biominerals (aragonite, vaterite, calcite) because they result from divergent evolution: biominerals were formed long after organisms diverged from one another 3,4. Despite such diversity, CaCO3 marine biominerals share a convergent character: adjacent crystals are similarly oriented 5-32. The reason for such convergence is unclear. Here, we show with quantitative, precise measurements at the nanoscale that the slight misorientation is consistently between 1°-40° in diverse biominerals. Can this slight misorientation confer a desirable materials property and therefore an evolutionary advantage to the forming organisms? We test and confirm this hypothesis with nanoindentation in diverse biominerals, geologic aragonite, and in abiotic, slightly misoriented, synthetic spherulites. Molecular dynamics (MD) simulations of bicrystals reveal that aragonite, vaterite, calcite, exhibit toughness peaks when they are misoriented by 10°, 20°, 30°, respectively, demonstrating that slight misorientation alone increases crack deflection and therefore fracture toughness. Slight misorientation, along with other previously known and co-existing toughening mechanisms, was selected repeatedly and convergently, during the course of evolution, to postpone fracture and thus provide organisms with competitive advantage. We anticipate slight misorientation-toughening to be a starting point for more sophisticated materials synthesis and additive manufacturing in many fields. Compared to previously known toughening mechanisms, in fact, the advantages of slight misorientation are that it can and does occur in synthetic materials, it requires one material only and no specific top-down architecture, it is easily achieved by self-assembly of organic molecules (e.g. aspirin, chocolate), polymers, metals, and ceramics 29 well beyond biominerals.
Source: Research Square
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Fonds De La Recherche Scientifique - FNRS, Office of Science, Multidisciplinary University Research Initiative, Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture, Office of Naval Research, Division of Materials Research, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, Air Force Office of Scientific Research, Army Research Office
Awards: G1102702650, G1286236842, G1286251239, G1314494723, G1380171086, G1414775356, G1445641779, G1523888516, G1816284028, G1863003419, G2037563265, G222768804, MAPPING OF TEMPORAL AND SPATIAL PHASE TRANSITIONS OF CACO3 IN ECHINODERM SKELETONS: KEY INSIGHTS INTO BASIC MECHANISMS IN BIOMINERALIZATION, G2618837358, G3040920244, Discovery of new crystallization pathways in forming biominerals, G30714459, G3083819904, G3174313537, G3310577945, G3488658013, Graduate Research Fellowship Program, G365575497, G3770966485, G3967535168, G419881185, G42916606, MAPPING OF TEMPORAL AND SPATIAL PHASE TRANSITIONS OF CAC03 IN ECHINODERM SKELETONS: KEY INSIGHTS..., G4501827968, G4917416065, G498139845, G5226628132, G5261056217, MAPPING OF TEMPORAL AND SPATIAL PHASE TRANSITIONS OF CACO3 IN ECHINODERM SKELETONS: KEY INSIGHTS INTO BASIC MECHANISMS IN BIOMINERALIZATION, G5648016710, G5721077460, G5849692847, G5912748570, G6098521345, G6191928423, G650090426, G6652958823, G7057920781, G7142813775, G7527358754, G7669948157, G804792905, G805243471, Discovery of New Phenomena in Biomineral Formation, G96172096, G969889393
OpenAlex ID: W4290673864