Electric Manipulation of Bioparticles and Macromolecules on Microfabricated Electrodes

Abstract

Bioparticle separation, bioparticle enrichment, and electric field-mediated immune detection were carried out on microfabricated semiconductor chips utilizing ac and dc electric fields. Microscale separation on a chip surface having an active area of approximately 16 mm2 was demonstrated for a mixture of Bacillus globigii spores and Escherichia coli bacteria. Dielectrophoretic enrichment was performed by collecting target bioparticles from a flow stream in flow cells of 47.5 microL, achieving a 20-fold increase in the concentration of E. coli bacteria from a diluted sample, a 28-fold enrichment for peripheral blood mononuclear cells from red blood cells, and a 30-fold increase in white blood cells from diluted whole blood. The ability to manipulate and collect bioparticles and macromolecules at microfabricated electrodes with ac and dc fields was further illustrated in electric field-mediated immunoassays for analyzing the biological identities of E. coli bacteria and B. globigii spores. According to these results, the electric methods for manipulating bioparticles present themselves as viable techniques for novel biomedical applications in sample preparations and biochemical assays on microelectrode arrays.

Immunomagnetic T cell capture from blood for PCR analysis using microfluidic systems

“…Devices were rinsed using technical grade 70% ethanol. Channels were pre-conditioned with 1% bovine serum albumin (BSA, SigmaAldrich Oakville, ON, Canada) to block non-specific adsorption (1 mL min 21 for 1 min, then 0.25 mL min 21 for 30 min, Y-device, or 10 mL min 21 for 1 min, then 2.5 mL min 21 for 5 min, FAT 3000), and filled with Dulbecco's phosphate buffered saline (PBS, Invitrogen, Burlington, ON, Canada).…”

“…The best results were obtained by then coating (stopped flow mode) with 20 mg mL 21 Protein A (Sigma-Aldrich) in PBS (1 h), followed by 20 mg mL 21 anti-human CD3 (in PBS, 30 min, clone HIT3a, BD PharMingen Canada, Mississauga, ON) and 1% BSA (in PBS, 30 min).…”

“…Bead beds were prepared as described, a second magnet was placed under the chip opposite the first, as shown in Fig. 3, then a 2 mL aliquot of blood was slowly layered on the bottom of reservoirs A and B, each pre-filled with 40 mL of supplemented RPMI 1640, and pumped through the chip for 30 min at 0.25 mL min 21 , followed by a PBS rinse for 20 min at 1 mL min 21 . The magnets were removed, the beads were pumped to the outlet reservoir, then collected by pipet for PCR analysis.…”

Influence of alternating current electrokinetic forces and torque on the elongation of immobilized DNA

“…3,5,6 The manipulation of small particles using dielectrophoresis and ac electrokinetic techniques in general has recently received considerable attention as an alternative to optical tweezers 7,8 or scanning probe techniques, 9,10 and is becoming a useful tool in molecular biology and biotechnology. Dielectrophoretic forces have been used to separate and manipulate cells, 2,11 bacteria, 12,13 viruses, 14 and submicron latex spheres. 5,15,16 Recently the dielectrophoretic manipulation of DNA molecules has led to applications such as the concentration of DNA molecules, [17][18][19] DNA-protein interaction studies, 20,21 and molecular surgery of DNA.…”

Polymer-Based Microfluidic Devices for Pharmacy, Biology and Tissue Engineering

“…An improvement was achieved by electrodeless DEP (EDEP), which allows the application of a high electric field without gas development and allows an increase of the dielectric response at low frequencies (<1 kHz) [139]. DEP has been reported successfully in applications on microfluidic devices to separate and manipulate a variety of biological cells such as bacteria, yeast and mammalian cells [177][178][179][180][181][182][183][184][185][186][187][188][189][190][191][192].…”