Chip for dielectrophoretic microbial capture, separation and detection II: experimental study

Abstract

In our previous paper we have modelled a dielectrophoretic force (DEP) and cell particle behavior in the microfluidic channel (Weber MU et al. 2022 Fluid-Screen Dielectrophoretic Microbial Capture, Separation and Detection I: Theoretical Study Nanotechnology submitted). Here we test and confirm the results of our modeling work by experimentally validating the theoretical design constraints of the Fluid-Screen ring electrode architecture. We have compared and tested the geometry and particle capture and separation performance of the two separate electrode designs (the ring and dot electrode structures) by investigating bacterial motion in response to the applied electric field. We have quantitatively evaluated the electroosmosis (EO) to positive DEP (PDEP) transition in both electrode designs and explained the differences in capture efficiency of the ring and dot electrode systems. The ring structure shows 99% efficiency of bacterial capture both for PDEP and for EO. Moreover, the ring structure shows an over 200 faster bacterial response to the electric field. We have also established that the ring electrode architecture, with appropriate structure periodicity and spacing, results in efficient capture and separation of microbial cells. We have identified several critical design constraints that are required to achieve high efficiency bacterial capture. We have established that the spacing between consecutive DEP traps smaller than the length of the depletion zone will ensure that the DEP force dominates bacterial motion over motility and Brownian motion.

Chip for dielectrophoretic microbial capture, separation and detection I: theoretical basis of electrode design

“…In summary our results show that designing the electrode structure to ensure structure periodicity with spacing between consecutive traps smaller than the length of the depletion zone will ensure that AC kinetic forces dominate bacterial motion over motility and Brownian motion (figure 10). We experimentally validate the electrode design in a companion paper in the same issue [22].…”

“…Our modelling makes testable predictions and shows towards the electrode design that ensures the efficient capture and separation of microbial cells. The experimental validation of the new electrode design is a topic of the companion paper in the same issue [22].…”

“…The high efficiency electrode system is achieved with a periodic electrode structure that results with a high density of electric field gradient realized over extensive length of the microfluidic channel. The experimental verification of the presented simulation and design is presented in Weber MU et al 2022 Chip for Dielectrophoretic Microbial Capture, Separation and Detection II: Experimental Study Nanotechnology in the same issue[22].…”

Editorial for ‘focus collection in memory of Prof Mark A Reed’

“…M Weber, a former member, contributed a series of articles on the theoretical and experimental studies of dielectrophoretic capture and detection of microbial cells [9,10], W Guan, a former member, wrote an article on modeling study of pyramidal silicon nanopores which can be an effective analytical tool for ion transport [11], Y Jung, also a former member, wrote an article on vertically aligned twodimensional (2D) molybdenum disulfide (MoS 2 ) layers for gas sensors [12]. And, M S Strano, a collaborator with Mark Reed, contributed an article on 2D hexagonal boron nitride (hBN) for quantum emission [13].…”