AC electrokinetic immobilization of influenza virus

Abstract

The use of alternating current (AC) electrokinetic forces, like dielectrophoresis and AC electroosmosis, as a simple and fast method to immobilize submicrometer objects onto nanoelectrode arrays is presented. Due to its medical relevance, the influenza virus is chosen as a model organism. One of the outstanding features is that the immobilization of viral material to the electrodes can be achieved permanently, allowing subsequent handling independently from the electrical setup. Thus, by using merely electric fields, we demonstrate that the need of prior chemical surface modification could become obsolete. The accumulation of viral material over time is observed by fluorescence microscopy. The influences of side effects like electrothermal fluid flow, causing a fluid motion above the electrodes and causing an intensity gradient within the electrode array, are discussed. Due to the improved resolution by combining fluorescence microscopy with deconvolution, it is shown that the viral material is mainly drawn to the electrode edge and to a lesser extent to the electrode surface.Finally, areas of application for this functionalization technique are presented.

Catalytic activity of glucose oxidase after dielectrophoretic immobilization on nanoelectrodes

“…This indicates that more GOX is immobilized on electrodes closer to the edge than at the center of the arrays. A similar distribution was observed for BSA, polystyrene beads, and virus material on similar electrode geometries [30,38,3]. It is a result of the electrokinetic effects acting on the molecules.…”

“…In order to ensure comparability, the same settings as in previous reports were chosen. Voltage and frequencies in the same range were proven as effective to immobilize very different protein samples, including HRP [11,12], BSA [30], and also virus material [3] or even small dye molecules [4].…”

“…DEP can be used to manipulate, classify, and sort cells [1]. Recently, more and more examples of DEP with smaller objects have been presented, for example, the separation of organelles [2] or the immobilization of virus particles [3] and even small dye molecules [4]. Proteins are also an interesting object for DEP, as there are many promising applications for DEP in protein separation, analysis or patterning and in biosensing [5,6].…”

Activity of AC electrokinetically immobilized horseradish peroxidase

“…As the force directly depends on the volume of the particle, the immobilization of smaller particles requires higher field gradients (see Equation 1), which can be produced by sharp electrode geometries. This way, submicron particles, for example, polystyrene beads and virus particles, can be separated or immobilized by DEP as well [4,5]. Although the mechanism behind the phenomenon is still a subject of recent studies and discussions [6][7][8][9][10], proteins [11,12], enzyme molecules [13], and even small dye molecules [14] were also manipulated by DEP.…”

Dielectrophoresis: An Approach to Increase Sensitivity, Reduce Response Time and to Suppress Nonspecific Binding in Biosensors?

“…DEP has also been applied for this purpose to immobilize viruses [ 113 ] or biomolecules [ 69 , 100 ] with retained functionality and could be an alternative to conventional biofunctionalization strategies for certain applications. For instance, Otto et al [ 69 ] immobilized IgG irreversibly onto a CMOS compatible silicon-based chip device with a regular array of more than 10 6 cylindrical sub-microelectrodes.…”