Enantioselective Colloidosomes Based on Chiral Silica Nanoparticles

Pickering emulsion is one of the principal methods for the formation of colloidosomes, offering a high level of control over their size and permeability. In this article, we describe the synthesis of chiral colloidosomes based on chiral silica nanoparticles produced in a sol-gel process combining a chiral (S)-N-1-phenylethyl-N′-triethoxysilylpropylurea precursor with tetraethyl orthosilicate. Chiral colloidosomes with a typical diameter of 1.7 μm were obtained from Pickering assembly of partially hydrophobized nanoparticles, as confirmed by electron microscopy and FTIR spectroscopy. The enantioselectivity of the silica colloidosomes was confirmed by enantioselective adsorption of racemic dichlorprop herbicide solutions onto the capsules, as proved by circular dichroism spectroscopy. Similar chiral colloidosomes could be synthesized in this facile and low-cost method, which are expected to be of interest in various chiral applications, especially those requiring controlled release. Overall, chiral colloidosomes could open a new gateway for the design of novel functional inorganic microcapsules.