Mechanistic Investigation of Nanoparticle Motion in Pulsed Voltage Miniaturized Electrical Field Flow Fractionation Device by in Situ Fluorescence Imaging - Analytical Methods & Tools for Lyophilization

Mechanistic Investigation of Nanoparticle Motion in Pulsed Voltage Miniaturized Electrical Field Flow Fractionation Device by in Situ Fluorescence Imaging
Received for review December 4, 2003. Accepted March 1, 2004.
Web Release Date: April 3, 2004
Alex Ieng Kin Lao, Yi-Kuen Lee, and I-Ming Hsing*
Anal. Chem.
ACS Publications
Copyright ? 2004 American Chemical Society
Department of Chemical Engineering and Department of Mechanical Engineering, Hong Kong University of Science and Technology, Hong Kong SAR
Abstract:
In our previous study, we reported a miniaturized electrical field flow fractionation device (-EFFF) that used a pulsed voltage (PV) to increase the effective electric field and, hence, improved the separation performance. In this work, we developed two -EFFFs with planar or segmented electrode design and investigated the particle movement in the flow channels under a PV. Numerical simulation was used to understand the electric field distribution in the -EFFFs. When the calculations for the -EFFF with a segmented electrode (segmented -EFFF) and the -EFFF with planar electrodes (planar -EFFF) are compared, a stronger electric field at the top electrode segments is found in the segmented -EFFF, with the strongest field at the edges of the electrode segments. Nanoparticle motion in both devices was in situ visualized by using a fluorescence microscope equipped with a CCD-camera. Results reveal that electrophoresis governs the nanoparticle movement in the planar -EFFF and dielectrophoresis dominates the movement in the segmented -EFFF. Two models are postulated to explain the experimental observations of the nanoparticle movement. The mechanistic understanding of controlling nanoparticle motion in a miniaturized environment will help the design and application of -EFFF for the separation of charged biomolecules (proteins and DNAs).
You can view the abstract online. A subscription is required to view the full text or it can be purchased online.