Inside Out Synthesis

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Science  20 Aug 2010:
Vol. 329, Issue 5994, pp. 885
DOI: 10.1126/science.329.5994.885-b

Methods to synthesize nanomaterials from aqueous metal precursors may one day build on biomineralization mechanisms. Microorganisms often mediate the formation of simple elemental metal or metal-oxide nanoparticulate precipitates at the cell surface. After exposing yeast cells to cerium ions, Jiang et al. instead observed the formation of needle-like cerium(III) phosphate (rather than oxide) nanoparticles on the cell surface, even though no phosphate ions were added to the solution. By controlling the pH during further exposure experiments, the authors concluded that the phosphate originated from inside the cells and was likely released as a toxicity response to high concentrations of cerium at the surface. The experiments showed that the precipitation step was decoupled from metabolic reactions and adsorption of Ce3+ ions onto the cell wall. In addition to providing a basis for understanding nanoparticle synthesis, the results imply that cerium and other potentially harmful rare earth elements that are present in low concentrations in environmental systems may be sequestered at the cell surface of indigenous microorganisms.

Chem. Geol. 10.1016/j.chemgeo.2010.07.010 (2010).

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