New Possibilities to Design Biogenic Calcite Particles. Influence of Cultivation Parameters and Purification on Coccolith Properties

Abstract

Coccolithen sind mikrostrukturierte Calcitpartikeln, die von Mikroalgen in der Natur produziert werden. Ihre komplex strukturierte Morphologie und enge Partikelgrößenverteilung unterscheidet sie von synthetischen Partikeln und macht sie interessant für verschiedenste Anwendungsgebiete. Coccolithen können nicht künstlich hergestellt werden und müssen deshalb durch Kultivierung gewonnen werden. In dieser Arbeit wird gezeigt, dass die Eigenschaften von Coccolithen nicht starr sind. Die Variation der Prozessparameter, Medienkomposition und Aufreinigungsstrategie ermöglicht bestimmte Eigenschaften von Coccolithen zu verändern. Dazu gehören die chemische Zusammensetzung, der Anteil von organischem Material und der Oberflächencharakter. Dadurch können Coccolithen zukünftig ihrem potenziellen Einsatzgebiet angepasst werden.

Therapeutic Applications of Phytoplankton, with an Emphasis on Diatoms and Coccolithophores

“…The exploitation of coccoliths as therapeutic carriers offers essential advantages such as a high surface area and readily available intricate mineralized morphology . The surface coverage of coccoliths can be controlled in vitro by tuning the purification process . As a contrast to other similar composition‐based particulate drug delivery systems (e.g., synthetic CaCO 3 microparticles), E. huxleyi extracted coccoliths and in vitro modification with enzymes provide almost five times higher surface area than the above mentioned systems, thus increasing the amount of immobilized enzymes (i.e., glucose oxidase and uricase) with preserved activity …”

“…A possible pathway for introducing new therapeutic functionalities into coccolith plates can be achieved in vivo by specific optimization of coccolithophore growth parameters (light, pH, temperature, culture media composition) . This enables the coccolithophore cell to produce coccolith with specific ions or molecules in their composition, specific size, morphology, or porosity …”

In Vivo Shaping of Inorganic Functional Devices using Microalgae

“…Coccolithophores like Emiliania huxleyi are unicellular marine microalgae, which cover themselves with elaborated finely‐patterned calcite (CaCO 3 ) disks, called coccoliths ( Figure 1 ). Coccoliths are mesoporous, 3D sieve‐like structures of about 3 µm in diameter with pore diameters ranging from micrometer to nanometer scale and possess a total pore volume of 0.05 cm 3 g −1 2,4. The overall geometry has a specific surface area of 19 m 2 g −1 2.…”

“…The nanoporosity of the coccoliths with special slit patterns suggests applications as micro/nano optical devices or fillers in adhesives 4,7. They may have also very interesting applications in the field of nanofluidics, as their nanopores and nanochannels can be used, for example, as sieving structures for the separation of particles or molecules 8.…”