Performance impact of dynamic surface coatings on polymeric insulator-based dielectrophoretic particle separators

Abstract

Efficient and robust particle separation and enrichment techniques are critical for a diverse range of lab-on-a-chip analytical devices including pathogen detection, sample preparation, high-throughput particle sorting, and biomedical diagnostics. Previously, using insulator-based dielectrophoresis (iDEP) in microfluidic glass devices, we demonstrated simultaneous particle separation and concentration of various biological organisms, polymer microbeads, and viruses. As an alternative to glass, we evaluate the performance of similar iDEP structures produced in polymer-based microfluidic devices. There are numerous processing and operational advantages that motivate our transition to polymers such as the availability of numerous innate chemical compositions for tailoring performance, mechanical robustness, economy of scale, and ease of thermoforming and mass manufacturing. The polymer chips we have evaluated are fabricated through an injection molding process of the commercially available cyclic olefin copolymer Zeonor 1060R. This publication is the first to demonstrate insulator-based dielectrophoretic biological particle differentiation in a polymeric device injection molded from a silicon master. The results demonstrate that the polymer devices achieve the same performance metrics as glass devices. We also demonstrate an effective means of enhancing performance of these microsystems in terms of system power demand through the use of a dynamic surface coating. We demonstrate that the commercially available nonionic block copolymer surfactant, Pluronic F127, has a strong interaction with the cyclic olefin copolymer at very low concentrations, positively impacting performance by decreasing the electric field necessary to achieve particle trapping by an order of magnitude. The presence of this dynamic surface coating, therefore, lowers the power required to operate such devices and minimizes Joule heating. The results of this study demonstrate that iDEP polymeric microfluidic devices with surfactant coatings provide an affordable engineering strategy for selective particle enrichment and sorting.

Tuning direct current streaming dielectrophoresis of proteins

“…We thus suspect that protein aggregation-barely resolvable in fluorescence microscopy studies-can enhance DEP forces leading to trapping at even lower electric fields. We furthermore find from calculations of the trapping criterion as developed previously [58][59][60] that the trapping condition is not satisfied in either iDEP device (see supplementary material 61 ).…”

Three dimensional passivated-electrode insulator-based dielectrophoresis

“…The reported applied signals in 3D pDEP devices are significantly low compared to traditional iDEP device, which typically require high voltages ($1000 Vpp) to operate. 10,11 However; for iDEP devices utilizing 3D constrictions, lower operating voltages have been reported by researchers. Braff et al reported some trapping of bacteria strains using a traditional iDEP device with 3D microstructures and electrodes in direct contact with the solution.…”

“…iDEP devices have been employed in the past to characterize particles including bacteria, viruses, cells, and beads. [10][11][12][13] Previously, three dimensional insulator-based dielectrophoresis (3D iDEP) devices have been used to increase sensitivity of iDEP devices. 14 Use of 3D insulating features has been shown to increase electric field gradient and the DEP force acting on particles.…”

Dielectrophoretic differentiation of mouse ovarian surface epithelial cells, macrophages, and fibroblasts using contactless dielectrophoresis

“…29 Such systems were proposed by Cummings and Singh 29 and have been applied successfully for manipulation of DNA, 30 separation of live and dead cells, 32,33 and separation of different species of cells. 34 Contactless dielectrophoresis (cDEP) is a new technique for manipulating cells which eliminates direct contact between the sample and electrodes. In cDEP, an electric field is generated in the sample channel by using two fluid electrode channels which are filled with a conductive fluid.…”