title: 3D Insulator-based dielectrophoresis using DC-biased, AC electric fields for selective bacterial trapping.
abstract: Insulator-based dielectrophoresis (iDEP) is a well-known technique that harnesses electric fields for separating, moving, and trapping biological particle samples. Recent work has shown that utilizing DC-biased AC electric fields can enhance the performance of iDEP devices. In this study, an iDEP device with 3D varying insulating structures analyzed in combination with DC biased AC fields is presented for the first time. Using our unique reactive ion etch lag, the mold for the 3D microfluidic chip is created with a photolithographic mask. The 3D iDEP devices, whose largest dimensions are 1 cm long, 0.18 cm wide, and 90 μm deep are then rapidly fabricated by curing a PDMS polymer in the glass mold. The 3D nature of the insulating microstructures allows for high trapping efficiency at potentials as low as 200 Vpp. In this work, separation of Escherichia coli from 1 μm beads and selective trapping of live Staphylococcus aureus cells from dead S. aureus cells is demonstrated. This is the first reported use of DC-biased AC fields to selectively trap bacteria in 3D iDEP microfluidic device and to efficiently separate particles where selectivity of DC iDEP is limited.
authors.affiliation: VT MEMS Laboratory, Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA.
authors.forename: Phillip
authors.initials: P
authors.lastname: Zellner
authors.forename: Tyler
authors.initials: T
authors.lastname: Shake
authors.forename: Yahya
authors.initials: Y
authors.lastname: Hosseini
authors.forename: Diana
authors.initials: D
authors.lastname: Nakidde
authors.forename: Maria V
authors.initials: MV
authors.lastname: Riquelme
authors.forename: Ali
authors.initials: A
authors.lastname: Sahari
authors.forename: Amy
authors.initials: A
authors.lastname: Pruden
authors.forename: Bahareh
authors.initials: B
authors.lastname: Behkam
authors.forename: Masoud
authors.initials: M
authors.lastname: Agah
mesh_terms: D004586:Electrophoresis / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D004926:Escherichia coli / Q000302:isolation & purification; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation; D011137:Polystyrenes; D013211:Staphylococcus aureus / Q000302:isolation & purification
chemical_list: D011137:Polystyrenes
keywords: 3D Fabrication; Cell trapping; Dielectrophoresis; Escherichia coli; Microfluidics; Staphylococcus aureus