Journal of nanoscience and nanotechnology, Jan 1, 2005
Diatoms are unicellular algae with silicified cell walls, which exhibit a high degree of symmetry... more Diatoms are unicellular algae with silicified cell walls, which exhibit a high degree of symmetry and complexity. Their diversity is extraordinarily high; estimates suggest that about 10(5) marine and limnic species may exist. Recently, it was shown that diatom frustules are mechanically resilient, statically sophisticated structures made of a tough glass-like composite. Consequently, to break the frustules, predators have to generate large forces and invest large amounts of energy. In addition, they need feeding tools (e.g., mandibles or gastric mills) which are hard, tough, and resilient enough to resist high stress and wear, which are bound to occur when they feed on biomineralized objects such as diatoms or other biomineralized protists. Indeed, many copepods feeding on diatoms possess, in analogy to the enamelcoated teeth of mammals, amazingly complex, silica-laced mandibles. The highly developed adaptations both to protect and to break diatoms indicate that selection pressure is high to optimize material properties and the geometry of the shells to achieve mechanical strength of the overall structure. This paper discusses the mechanical challenges which force the development of mechanical defenses, and the structural components of the diatom frustules which indicate that evolutionary optimization has led to mechanically sophisticated structures. Understanding the diatom frustule from the nanometer scale up to the whole shell will provide new insights to advanced combinations of nanostructured composite ceramic materials and lightweight architecture for technological applications.
Biologists, and diatomists in particular, have long studied the properties of single-cell algae, ... more Biologists, and diatomists in particular, have long studied the properties of single-cell algae, and engineers are just discovering how to exploit features unique to these organisms. Their uniform nanopore structure, microchannels, chemical inertness, and silica microcrystal structure suggest many nanoscale applications. This paper proposes three potential research initiatives taking advantage of diatom morphology and mechanical and chemical properties: (1) embedding diatom frustules in a metal-film membrane; (2) magnetizing frustules for pinpoint drug delivery; and (3) producing silica nanopowders from frustules. The potential benefits of each initiative and its technical challenges are outlined.
... The high degree of specificity indicates that diatoms as a group are well defended against vi... more ... The high degree of specificity indicates that diatoms as a group are well defended against viruses. The possible nature of the defense can be deduced from another Page 333. I. WHY ARMOR 319 bloom-forming groupcolonial species of Phaeocystis. Hamm etal.(1999) have ...
Colonies of the prymnesiophyte marine microalga Phaeocystis globosa were tested for mechanical pr... more Colonies of the prymnesiophyte marine microalga Phaeocystis globosa were tested for mechanical properties, permeability and biochemical composition using the micropipette aspiration technique. We found that the Phaeocystis colony is enclosed by a thin, yet very strong, ...
In both field samples and cultures the total amount of sugar and of carbon in colonies of Phaeocy... more In both field samples and cultures the total amount of sugar and of carbon in colonies of Phaeocystis globosa was correlated with colony surface area, suggesting a hollow structure. A conceptual model based on biochemical data and on the assumption that the mucus occurs as a ...
Abstract: The fate of a Phaeocystis globosa bloom in the Southern North Sea off Belgium, the Neth... more Abstract: The fate of a Phaeocystis globosa bloom in the Southern North Sea off Belgium, the Netherlands and Germany in Mai 1995 was investigated during a cruise with RV Belgica. We used fatty acids as biomarkers to follow the fate of Phaeocystis-derived biomass of a ...
Journal of nanoscience and nanotechnology, Jan 1, 2005
Diatoms are unicellular algae with silicified cell walls, which exhibit a high degree of symmetry... more Diatoms are unicellular algae with silicified cell walls, which exhibit a high degree of symmetry and complexity. Their diversity is extraordinarily high; estimates suggest that about 10(5) marine and limnic species may exist. Recently, it was shown that diatom frustules are mechanically resilient, statically sophisticated structures made of a tough glass-like composite. Consequently, to break the frustules, predators have to generate large forces and invest large amounts of energy. In addition, they need feeding tools (e.g., mandibles or gastric mills) which are hard, tough, and resilient enough to resist high stress and wear, which are bound to occur when they feed on biomineralized objects such as diatoms or other biomineralized protists. Indeed, many copepods feeding on diatoms possess, in analogy to the enamelcoated teeth of mammals, amazingly complex, silica-laced mandibles. The highly developed adaptations both to protect and to break diatoms indicate that selection pressure is high to optimize material properties and the geometry of the shells to achieve mechanical strength of the overall structure. This paper discusses the mechanical challenges which force the development of mechanical defenses, and the structural components of the diatom frustules which indicate that evolutionary optimization has led to mechanically sophisticated structures. Understanding the diatom frustule from the nanometer scale up to the whole shell will provide new insights to advanced combinations of nanostructured composite ceramic materials and lightweight architecture for technological applications.
Biologists, and diatomists in particular, have long studied the properties of single-cell algae, ... more Biologists, and diatomists in particular, have long studied the properties of single-cell algae, and engineers are just discovering how to exploit features unique to these organisms. Their uniform nanopore structure, microchannels, chemical inertness, and silica microcrystal structure suggest many nanoscale applications. This paper proposes three potential research initiatives taking advantage of diatom morphology and mechanical and chemical properties: (1) embedding diatom frustules in a metal-film membrane; (2) magnetizing frustules for pinpoint drug delivery; and (3) producing silica nanopowders from frustules. The potential benefits of each initiative and its technical challenges are outlined.
... The high degree of specificity indicates that diatoms as a group are well defended against vi... more ... The high degree of specificity indicates that diatoms as a group are well defended against viruses. The possible nature of the defense can be deduced from another Page 333. I. WHY ARMOR 319 bloom-forming groupcolonial species of Phaeocystis. Hamm etal.(1999) have ...
Colonies of the prymnesiophyte marine microalga Phaeocystis globosa were tested for mechanical pr... more Colonies of the prymnesiophyte marine microalga Phaeocystis globosa were tested for mechanical properties, permeability and biochemical composition using the micropipette aspiration technique. We found that the Phaeocystis colony is enclosed by a thin, yet very strong, ...
In both field samples and cultures the total amount of sugar and of carbon in colonies of Phaeocy... more In both field samples and cultures the total amount of sugar and of carbon in colonies of Phaeocystis globosa was correlated with colony surface area, suggesting a hollow structure. A conceptual model based on biochemical data and on the assumption that the mucus occurs as a ...
Abstract: The fate of a Phaeocystis globosa bloom in the Southern North Sea off Belgium, the Neth... more Abstract: The fate of a Phaeocystis globosa bloom in the Southern North Sea off Belgium, the Netherlands and Germany in Mai 1995 was investigated during a cruise with RV Belgica. We used fatty acids as biomarkers to follow the fate of Phaeocystis-derived biomass of a ...
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