Electrophoretic Migration and Axial Diffusion of Individual Nanoparticles in Cylindrical Nanopores

TitleElectrophoretic Migration and Axial Diffusion of Individual Nanoparticles in Cylindrical Nanopores
Publication TypeJournal Article
Year of Publication2012
AuthorsHan R, Wang GF, Qi SD, Ma CB, Yeung ES
Journal TitleJournal of Physical Chemistry C
Volume116
Pages18460-18468
Date Published08/30
Type of ArticleArticle
ISBN Number1932-7447
Accession NumberWOS:000308120000057
Keywordsadsorption, anodic alumina, capillary-electrophoresis, MEMBRANES, MOTION, porous alumina, PROTEIN MOLECULES, silica, size-exclusion chromatography, spherical-particle
Abstract

Membranes with straight, vertical nanopores have found widespread applications in chemical and biological sciences, including separation, detection, catalysis, and drug delivery. They can also serve as a model system to understand molecular behavior and fundamental mechanisms of separation, bridging the gap between conventional model systems such as flat surfaces and real chromatographic stationary phases such as micrometer-sized porous particles. We recently found that the axial motion of individual biomolecules inside nanopores can be significantly slower than in bulk solution. This suggests that either chromatographic adsorption was present and/or the viscosity inside the nanopores was unusually high. In this study, we measured the electrophoretic motion as well as the axial diffusion of individual nanoparticles in cylindrical alumina nanopores. We found that the electrophoretic mobilities and the diffusion coefficients of polystyrene nanoparticles were both substantially smaller compared to bulk solution independent of particle size or pore diameter. The results imply that the apparent solution viscosity in nanodomains is anomalous.

URL<Go to ISI>://WOS:000308120000057
DOI10.1021/jp303855d
Alternate JournalJ. Phys. Chem. C