A dielectrophoresis-impedance method for protein detection and analysis

Abstract

Dielectrophoresis (DEP) has increasingly been used for the assessment of the electrical properties of molecular scale objects including proteins, DNA, nanotubes and nanowires. However, whilst techniques have been developed for the electrical characterisation of frequency-dependent DEP response, biomolecular study is usually limited to observation using fluorescent markers, limiting its applicability as a characterisation tool. In this paper we present a label-free, impedance-based method of characterisation applied to the determination of the electrical properties of colloidal protein molecules, specifically Bovine Serum Albumin (BSA). By monitoring the impedance between electrodes as proteins collect, it is shown to be possible to observe multi-dispersion behaviour. A DEP dispersion exhibited at 400 kHz is attributable to the orientational dispersion of the molecule, whilst a second, higher-frequency dispersion is attributed to a Maxwell-Wagner type dispersion; changes in behaviour with medium conductivity suggest that this is strongly influenced by the electrical double layer surrounding the molecule.

Fluid-Screen as a real time dielectrophoretic method for universal microbial capture

“…15 ). In recent years the development of DEP separation techniques for proteins and other macromolecules also gained momentum [16][17][18] .In this paper we show the new DEP bacterial capture and separation method, that overcomes those notorious limitations. We call our DEP microbial capture method Fluid-Screen (FS).…”

Biological Particle Control and Separation using Active Forces in Microfluidic Environments

“…Viefhues et al [24] perform dielectrophoretic mobility shift assay of DNA complexes as well as pure DNA in a nanofluidic DEP system to demonstrate new technique in detection of different DNA variants, including protein-DNA complexes. Manipulation of proteins has been achieved by Mohamad et al [25]. They use DEP to capture and characterize the electrical properties of colloidal protein molecule, i.e., bovine serum albumin (BSA), based on the molecule dispersion impedance exhibited at particular frequencies, which are influenced by the electrical double layer surrounding the molecule.…”

“…DEP has shown rapid progress into exploration of extremely small bioparticle manipulation, i.e., virus, nucleic acids, and protein. In particular, demonstration of DNA sorting [23] and impedance-based protein capturing [25] prove the potential for nanoscale application, as well as genetic and molecular biology studies. MAG is advantageous in selective manipulation benefited by biofunctionalization of magnetic micro-/ nanoparticle for affinity binding to target bioparticles.…”

Fine-Tuning Electrokinetic Injections Considering Nonlinear Electrokinetic Effects in Insulator-Based Devices

“…Electrokinetics (EK) is one of the main branches of microfluidics due to its flexibility and ease of application, since a single applied voltage can drive both the liquid and bioparticles present in a sample [1,2]. In recent years, there has been significant progress in the development of microscale electrokinetic EK methodologies for the identification, separation, enrichment, analysis, and detection of a wide array of bioparticles, ranging from macromolecules to parasites [3][4][5][6]. Furthermore, EK devices offer the unique potential of being able to exploit both linear and nonlinear EK phenomena [7,8] within the same system, leading to highly selective and discriminatory separation and purification processes [9,10].…”