Biominerals possess shapes, structures and properties not found in synthetic minerals. The dream of exploiting the biological principles of controlled mineral formation in materials chemistry inspires a large community to investigate the underlying mechanisms through biomimetic mineralisation experiments.[1] The defining characteristics of biominerals arise from the interplay of the mineral with a macromolecular matrix, which directs crystal nucleation and growth. Within this three dimensional biomolecular assembly, the developing mineral interacts with acidic macromolecules, either dissolved in the crystallisation medium or associated with an insoluble templating structure.[2]
CryoTEM has proven to be a powerful tool to investigate – with great detail – the nucleation and growth of different mineral systems, including calcium carbonate[3], calcium phosphate,[4] iron oxide[5] and silica.[6] It also allows us to study how organic-inorganic interactions at interfaces affect the crystallisation from solution.[7-9] Interestingly we find that all these pathways involve nanometer sized building blocks that have been termed prenucleation clusters,[7-9] prenucleation complexes[4] and primary particles.[5-6] Using time resolved cryoTEM we now also demonstrate how multistep nucleation pathways are altered through the influence of polypeptide based additives.[10] Controlling the pathways of nucleation and growth may help us to ultimately to control the size, shape and orientation of the crystals and optimise them for specific technological applications.[11]
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[3] Pouget, et al., J. Am. Chem. Soc. 2010, 132, 11560.
[4] Habraken, et al., Nat. Commun. 2013, 4.
[5] Baumgartner, et al., Nat. Mater. 2013, 12, 310.
[6] Carcouet, et al., Nano Lett. 2014, 14, 1433.
[7] Pouget, et al., Science 2009, 323, 1455.
[8] Dey, et al., Nat. Mater. 2010, 9, 1010.
[9] Nudelman, et al., Nat. Mater. 2010, 9, 1004.
[10] Dey, et al., Faraday Discuss. 2015, 179, 215.
[11] De Yoreo, et al., Science 2015, 349, 498.