Refinement of insulator-based dielectrophoresis

Abstract

The ability to separate analytes with increasingly similar properties drives the field of separation science. One way to achieve such separations is using trapping and streaming dielectrophoresis (DEP), which directly exploits the subtle differences in the electrophysical properties of analytes. The non-uniform fields necessary for DEP can be formed using various insulator shapes in microchannels. Current insulator shapes include triangles, diamonds, circles, and rectangles. However, all of these insulators pose problems for trapping, streaming, and sorting (deflection) as the induced fields/gradients are not behaviorally consistent across the lateral dimension. This leads to analytes experiencing different forces depending on their pathline in the microchannel and result in low resolution separations. Based on an iterative process that explored approximately 40 different insulator shapes, a design was chosen that indicated improved particle streamlines, better trapping efficiency, and consistent electrical environments across the lateral dimension. The design was assessed by simulations where the electric field, gradient of the electric field squared, and the ratio of the two were plotted. The improved design includes a unique new multi-length scale element. The multi-length scale structure streamlines the analyte(s) and improves homogeneity in the lateral dimension, while still achieving high gradients necessary for analyte separation using DEP. The design is calculated to keep analytes on the centerline which should improve resolution, and eliminate extraneous trapping zones. Behaviors consistent with the features of the simulations were observed in proof of principle experiments using representative test probes.

Differential Biophysical Behaviors of Closely Related Strains of Salmonella

“…Finite element modeling (COMSOL, Inc., Burlington, MA, United States) of the distribution of the electric field in the microchannel was performed as previously detailed (Crowther and Hayes, 2017). The AC/DC module was used to interrogate the E , ∇| E | 2 , and ∇| E | 2 E 2 • E in an accurately scaled 2D model of the microchannel.…”

On the use of correction factors for the mathematical modeling of insulator based dielectrophoretic devices

“…Many research groups have dedicated significant efforts to the modeling of iDEP‐based microfluidic devices; a large majority of reports on DEP include modeling efforts . Mathematical modeling of any type of EK system is not a simple task, as several phenomena can arise in these devices, including particle size distribution, particle‐particle interactions , temperature gradients , electro thermal flows , and Joule heating effects .…”

Stacked Dual‐Pore Architecture for Deciphering and Manipulating Dynamics of Individual Nanoparticles

“…Most recently, iDEP has been developed to induce non‐uniform electric fields in confined micro/nano‐environments, thus helping to create tailored local environments to accurately control and manipulate the (bio)analytes. [ 42 ] As our dual‐pore constructs are made from polymeric resists (insulating material), these constructs could be a novel and robust tool for the investigation of genuine 3D iDEP systems.…”