Capillary electrophoretic separation of nanoparticles
Open Access
- 26 January 2011
- journal article
- research article
- Published by Springer Nature in Analytical and Bioanalytical Chemistry
- Vol. 399 (8), 2831-2842
- https://doi.org/10.1007/s00216-011-4650-y
Abstract
In the present work, CdSe nanocrystals (NCs) synthesized with a trioctylphosphine surface passivation layer were modified using amphiphilic molecules to form a surface bilayer capable of providing stable NCs aqueous solutions. Such modified nanocrystals were used as a test solute in order to analyze new electrophoretic phenomena, by applying a micellar plug as a separation tool for discriminating nanocrystals between micellar and micelle-free zones during electrophoresis. The distribution of NCs between both zones depended on the affinity of nanocrystals towards the micellar zone, and this relies on the kind of surface ligands attached to the NCs, as well as electrophoretic conditions applied. In this case, the NCs that migrated within a micellar zone can be focused using a preconcentration mechanism. By modifying electrophoretic conditions, NCs were forced to migrate outside the micellar zone in the form of a typical CZE peak. In this situation, a two-order difference in separation efficiencies, in terms of theoretical plates, was observed between focused NCs (N ~ 107) and a typical CZE peak for NCs (N ~ 105). By applying the amino-functionalized NCs the preconcentration of NCs, using a micellar plug, was examined, with the conclusion that preconcentration efficiency, in terms of the enhancement factor for peak height (SEFheight) can be, at least 20. The distribution effect was applied to separate CdSe/ZnS NCs encapsulated in silica, as well as surface-modified with DNA, which allows the estimation of the yield of conjugation of biologically active molecules to a particle surface. Micellar plug as a tool to separate nanoparticles: nanocrystals coated with an ionic surfactant form a pseudomicellar system with a non-ionic surfactant. Appling this system in the form of a plug, in capillary electrophoresis, nanocrystals preconcentration within a plug or release from a plug, depending on applied conditions, were observed. This was used to discriminate particles vs. particles bioconjugated with aptamerKeywords
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