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Borosilicate nanoparticles prepared by exothermic phase separation

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Nanoparticles play an important role in chemical and biological sciences due to their ability to bind and concentrate many molecules on their surface1. Polymers1,2 and silica3,4,5,6,7 are widely used to make nanoparticles, but efforts to make nanoparticles from borosilicate glass—which exhibits high tolerance to chemicals and solvents, combined with excellent mechanical and thermal stability8,9,10—have proved unsuccessful. Here we show that borosilicate nanoparticles (100–500 nm in size) can be synthesized by simply mixing a silicon–boron binary oxide solution, prepared using non-aqueous organic solvents, with water. This induces a vigorous exothermic phase separation in which borosilicate nanoparticles burst out of a silica phase. In addition to potential applications in the life sciences, monodisperse borosilicate particles could also have applications in the production of photonic bandgap devices with high optical contrast, contrast agents for ultrasonic microscopy or chemical filtration membranes11,12,13.

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Figure 1: Process for preparation of the borosilicate sol and reaction products formed when mixing the sol with water.
Figure 2: Characterization of the nanoparticles by HRTEM and EELS.
Figure 3: Characterization of the reaction products by FTIR spectroscopy.
Figure 4: Solid- and liquid-state NMR spectra for characterization of the reaction process.
Figure 5: Solid-state NMR spectra of the nanoparticles.

Change history

  • 23 September 2008

    The original version of this letter published online has now been corrected at the end of the abstract, in Fig. 1b, Fig. 5 caption, and in the 'NMR Spectroscopy' section of the Methods. These corrections have been made for all versions of the letter.


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The authors acknowledge aid from the Swiss National Science Foundation (grant no. 200020-101466) and thank A.-S. Chauvin, P. Pechy and especially A. Abraham for help with the NMR experiments and Y. Moser for help with the temperature measurements.

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Authors and Affiliations



V.K.P., J.-B.O. and A.S. conceived, designed and performed the experiments. V.K.P., J.-B.O., M.C. and M.A.M.G. analysed the data. V.K.P. and M.A.M.G. co-wrote the paper. M.C. was responsible for the EELS analysis.

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Correspondence to Martin A. M. Gijs.

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Parashar, V., Orhan, JB., Sayah, A. et al. Borosilicate nanoparticles prepared by exothermic phase separation. Nature Nanotech 3, 589–594 (2008).

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