AC electrokinetic immobilization of organic dye molecules

Laux, Eva‐Maria; Wenger, Christian; Bier, Frank F.; Hölzel, Ralph

doi:10.1007/s00216-020-02480-4

Cited by 4 publications

(6 citation statements)

References 53 publications

(58 reference statements)

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“…To maximize immobilization efficiency, the applied frequency was systematically investigated from 10 to 20 kHz. Based on previous publications, this is a valid frequency range to immobilize sub-micrometer objects like nanospheres and macromolecules [17,[43][44][45]. Frequencies below 5 kHz promote the formation of bubbles due to electrolysis [22,44,48], whereas high frequencies lead to electrothermal fluid flow [49].…”

Section: Definition Of Experimental Parametersmentioning

confidence: 99%

“…Particles can be accumulated, transported, separated, trapped, and characterized. Studies on the DEP manipulation of biological objects have progressed from the micrometer range like cells [2][3][4][5] and bacteria [6][7][8][9], to viruses [10][11][12], proteins [13,14], DNA [15,16], and even small molecules [17]. A commercial use has been demonstrated as well [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

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AC electrokinetic immobilization of influenza virus

et al. 2022

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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.

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Section: Definition Of Experimental Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

AC electrokinetic immobilization of influenza virus

et al. 2022

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“…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. As the immobilization on nanoelectrodes is label free and accomplished in seconds [15,16], DEP might become a method of choice for the production of biosensors.…”

Section: Introductionmentioning

confidence: 99%

Activity of AC electrokinetically immobilized horseradish peroxidase

et al. 2022

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Dielectrophoresis (DEP) is an AC electrokinetic effect mainly used to manipulate cells. Smaller particles, like virions, antibodies, enzymes, and even dye molecules can be immobilized by DEP as well. In principle, it was shown that enzymes are active after immobilization by DEP, but no quantification of the retained activity was reported so far. In this study, the activity of the enzyme horseradish peroxidase (HRP) is quantified after immobilization by DEP. For this, HRP is immobilized on regular arrays of titanium nitride ring electrodes of 500 nm diameter and 20 nm widths. The activity of HRP on the electrode chip is measured with a limit of detection of 60 fg HRP by observing the enzymatic turnover of Amplex Red and H2O2 to fluorescent resorufin by fluorescence microscopy. The initial activity of the permanently immobilized HRP equals up to 45% of the activity that can be expected for an ideal monolayer of HRP molecules on all electrodes of the array. Localization of the immobilizate on the electrodes is accomplished by staining with the fluorescent product of the enzyme reaction. The high residual activity of enzymes after AC field induced immobilization shows the method's suitability for biosensing and research applications.

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“…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].…”

Section: Dielectrophoresismentioning

confidence: 99%

“…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].…”

Section: Introductionmentioning

confidence: 99%

Catalytic activity of glucose oxidase after dielectrophoretic immobilization on nanoelectrodes

2023

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Dielectrophoresis (DEP) is an AC electrokinetic effect that is proven to be effective for the immobilization of not only cells, but also of macromolecules, for example, antibodies and enzyme molecules. In our previous work, we have already demonstrated the high catalytic activity of immobilized horseradish peroxidase after DEP. To evaluate the suitability of the immobilization method for sensing or research in general, we want to test it for other enzymes, too. In this study, glucose oxidase (GOX) from Aspergillus niger was immobilized on TiN nanoelectrode arrays by DEP. Fluorescence microscopy showed the intrinsic fluorescence of the immobilized enzymes flavin cofactor on the electrodes. The catalytic activity of immobilized GOX was detectable, but a fraction of less than 1.3% of the maximum activity that was expected for a full monolayer of immobilized enzymes on all electrodes was stable for multiple measurement cycles. Therefore, the effect of DEP immobilization on the catalytic activity strongly depends on the used enzyme.

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AC electrokinetic immobilization of organic dye molecules

Cited by 4 publications

References 53 publications

AC electrokinetic immobilization of influenza virus

AC electrokinetic immobilization of influenza virus

Activity of AC electrokinetically immobilized horseradish peroxidase

Catalytic activity of glucose oxidase after dielectrophoretic immobilization on nanoelectrodes

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