Circular Electrodes Research Articles

Practical Optimization of Highly Sensitive AZO Photoconductor With Circular Electrode Scheme

Highly responsive ZnO-based photoconductors with a circular electrode scheme are introduced in this paper. Some cost-effective samples were fabricated through simple chemical routes and conventional photolithography methods. Al:ZnO thin films with a high density of hole trap states were prepared after several optimizations during the synthesis process. Circular electrodes with low ohmic contact resistances were formed by optimizing the metallization process. Then, the prepared prototypes were analyzed and their specifications were measured. Performance of the devices was also investigated by using a device simulator. The experimental data showed good agreement with the simulation results. Such that the high responsivity of about 1.9 × 104 AW–1 and signal-to-noise ratio of 9.14 × 103 were recorded after optimization of annealing temperature (at 350 °C), under a weak ultraviolet illumination of 268.27 μW⋅cm–2 at 253 nm wavelength.

Comparative Study on EDM of Ti-6Al-4V Using Circular and Convex Shaped Electrodes

As on today, Electrical Discharge Machining (EDM) is world famous unconventional machining process for electrically conductive materials. In this project work, Ti-6Al-4V is performed in electrical discharge machining using differently shaped (circular and convex) copper electrode. The machining parameters considered are the pulse on- time, pulse off-time, voltage and current to investigate machining characteristics like material removal rate and tool wear rate. Taguchi method is applied to frame experimental design. Ti-6Al-4V finds wide usage in industrial applications such as marine, aerospace, bio-medical and so on.

Analysis of Fine Dust Removal Time Using Circular Hole Electrodes of Various Sizes by Corona Discharge

Corona discharge technology is used widely for air purification in laboratory experiments and industry. On the other hand, corona discharge technology has the disadvantage of requiring large-sized electrodes. Therefore, research is needed to reduce the size of the electrodes. In this study, circular hole aluminum electrodes and an air purifier system were designed to reduce the size of the electrodes. Several sets of power conversions were performed to generate a corona discharge. The system consisted of a half bridge inverter, step-up transformer, and Cockcroft Walton circuit. The range of input and output voltages was 30–70 V and 20–25 kV, respectively. A corona discharge was generated by the output voltage. The system could remove smoke in less time with a combination of 13 kHz and an electrode with a hole diameter of 0.2 cm than with the other combinations. The electrode hole diameter affected the removal time of species such as hydrogen carbon hydrogen oxygen (HCHO, formaldehyde), total volatile organic compounds (TVOC), and fine dust, which was confirmed by laboratory experiments. Mathematical derivation and experiments were carried out to prove the validity of the approach; the Clean Air Delivery Rate (CADR) index was 480 μm/m3.

High-Throughput Performance Testing in 25-Electrode Array Fuel Cell for Platinum Group Metal-Free Catalysts

Hydrogen-fueled polymer electrolyte fuel cell (PEFCs) systems are currently utilized as high efficiency, low emission power sources for a variety of applications, most notably for electric vehicles such as the Toyota Mirai. The high cost of platinum, widely used as the electrocatalyst in PEFCs, is one of main barriers to the widespread and economically-viable implementation of fuel cell vehicles. Many research efforts have successfully developed platinum group metal-free (PGM-free) electrocatalysts for the oxygen reduction reaction (ORR), including those in the U.S. Department of Energy, Fuel Cell Technologies Office’s Electrocatalysis Consortium (ElectroCat)1-3. High-throughput catalyst synthesis, activity evaluation, and performance testing are core activities within ElectroCat aimed at accelerating the discovery and implementation of ORR electrocatalysts. High-throughput catalyst activity screening is accomplished using a newly-developed multi-channel flow double electrode, allowing activity measurements of four catalysts simultaneously deposited on glassy carbon electrodes using an automated robotic catalyst ink dispensing system with a nano-liter injector4. The purpose of this project is to accelerate the development of PGM-free catalysts using high-throughput performance evaluation in a 25-electrode array cell (NuVant) which has a common counter electrode and five independent flow channels. This system allows simultaneous performance testing and characterization of 25 types of catalyst in a membrane-electrode assembly (MEA) with five gas supply manifolds. Electrode fabrication is one of the most challenging steps in the catalyst-coated membrane (CCM) fabrication process for the array cell. A custom-designed heated vacuum table mounted on the computer-controlled XY table is used to make the 25-electrode CCM to avoid shrinkage and swelling of the catalyst layer and the membrane during the fabrication. The nano-pipette automated ink deposition system is being used for precise and even catalyst ink deposition across the small circular array electrodes. Scanning electron microscopy of the electrode is being utilized to confirm uniform and robust microstructures after the direct fabrication method. The 25-electrode set-up can accelerate PGM-free catalyst evaluation and optimization of electrode composition with the additional advantage of minimizing the amount of material required since the area of each electrode in the array is less than 1 cm2. Acknowledgements This work was supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office under the auspices of the Electrocatalysis Consortium (ElectroCat). Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, under contract DE-AC-02-06CH11357. References U. Martinez, S. K. Babu, E. F. Holby, K. Artyushkova, L. Lin, H. T. Chung, G. M. Purdy, and P. Zelenay, 232nd ECS Meeting, National Harbor, MD, October 1-5, 2017.S.T. Thompson, A.R. Wilson, P. Zelenay, D.J. Myers, K.L. More, K.C. Neyerlin, and D. Papageorgopoulos, Solid State Ionics, 319 (2018) 68-76.H.T. Chung, D.A. Cullen, D. Higgins, B.T. Sneed, E.F. Holby, K.L. More, P. Zelenay, Science 357 (2017) 479–484.J. Park, N. Kariuki, D. J. Myers, H. Chung, U. Martinez, P. Zelenay, 233nd ECS Meeting, Seattle, WA, May 13-17, 2018.

Discovery of a Voltage-Stimulated Heartbeat Effect in Droplets of Liquid Gallium.

Chemomechanical effects are known to initiate fluid oscillations in certain liquid metals; however, they typically produce an irregular motion that is difficult to deactivate or control. Here we show that stimulating liquid gallium with electrochemistry can cause a metal drop to exhibit a heart beating effect by shape shifting at a telltale frequency. Unlike the effects reported in the past for mercury, the symmetry-breaking forces generated by using gallium propel the drop several millimeters with velocities of the order of 1cm per second. We demonstrate pulsating dynamics between 0 and 610 beats per minute for 50-150 μL droplets in a NaOH electrolyte at 34 °C. The underlying mechanism is a self-regulating cycle initiated by fast electrochemical oxidation that adjusts the drop's surface tension and causes a transformation from spherical to pancake form, followed by detachment from the circular electrode. As the beat frequency can be activated and controlled using a dc voltage, the electrochemical mechanism opens the way for fluid-based timers and actuators.

PB16. Prefrontal bipolar versus multichannel tDCS: Impact on working memory performance

Introduction Recent studies show that tDCS applied over the left dorsolateral prefrontal cortex (lDLPFC) can successfully affect working memory (WM) performance ( Coffman et al., 2014 ). The present study investigates the influences of a classical bipolar and more focal multichannel tDCS over the lDLPFC on WM performance (2-back task) and continuous performance task (CPT) as non target task as well as on resting-state EEG oscillations and ERPs. Methods The study was approved by the Ethic Committee of the Faculty of Medicine Christian-Albrechts University Kiel. Eighteen healthy young adults (18–30 years) participated in the study. Participants were stimulated 3 times (bipolar, multichannel, sham stimulation in randomized order) over the lDLPFC for 20 min, minimum period between sessions was 7 days. For bipolar stimulation 1 mA was applied by two circular saline-soaked surface sponge electrodes (25 cm2), with anode positioned over F3 and reference over FP2. For multichannel tDCS we used five 3.14 cm2 circular PiStim electrodes (Neuroelectrics, Barcelona, Spain), positioned at AF3 (897 uA), AF7 (284 uA), F3 (819 uA), FP2 (−1000 uA) and T7 (−1000 uA). After stimulation EEG at rest (2 min eyes closed, 2 min eyes open) and during 2-back and CPT performance was recorded. Results Behavioral results show significant improvement of accuracy in the 2-back task after multichannel and bipolar tDCS compared to sham stimulation but not for CPT performance. Incidence and intensity of aversive side effects did not differ between multichannel, bipolar or sham tDCS. Conclusion Our results show that multichannel and bipolar tDCS over the lDLPFC have the potential of modulating WM performance, with multifocal stimulation not eliciting greater effects, which is in contrary to results of motor cortex area stimulation ( Fischer et al., 2017 ). Since WM performance but not non target-task performance was affected, our results suggest that the area of interest has been successfully stimulated. Our results on aversive side effect underline the tolerability of multichannel tDCS and bipolar tDCS. Additionally, participants were not able to discriminate real and sham stimulation effectively. However, future analyses, especially of obtained EEG data, will give further insight on the efficacy and tolerability of multichannel tDCS versus bipolar tDCS. This study was conducted as part of the STIPED program. STIPED has received funding from European Union’s Horizon2020 research and innovation programme under grant agreement No. 731827 .

PB19. tDCS in the left DLPFC: When to stimulate and which cognitive domains it affects

Aim Applications of transcranial direct current stimulation (tDCS) aim at targeting specific cognitive domains. Optimization of tDCS protocols is therefore crucial. It has been suggested to combine tDCS with a cognitive task aiming at the networks related to the targeted cognitive domain. The present study investigates (1) the timing of tDCS in relation to the target task (working memory). (2) Specificity of DLPFC-stimulation on executive functions. Methods A total of 80 subjects aged 18–30 participated in the study; eight were excluded for IQ above 130 (40 female; age M = 22.0, SD = 3.2; IQ M = 107.2, SD = 11.1). Twenty-four hours after baseline examination (T0), participants were randomly allocated to one of four different conditions of tDCS timing: Verum stimulation (1) before, (2) during and (3) after performing an adaptive n-back task (T1) as well as (4) sham stimulation during the n-back task. 1.5 mA anodal tDCS was delivered through the Starstim system for 17 min (Neuroelectrics, Barcelona, Spain). The size of the circular active electrode (left DLPFC) was 8 cm2 and of the reference electrode 25 cm2 (contralateral mastoid). Cognitive examination covered attention, executive functions (working memory, cognitive flexibility, inhibitory control), verbal and non-verbal memory, and visuo-spatial functioning. Repeated measurement ANOVA was performed to compare each verum condition to sham stimulation. Results Concerning executive functions, participants in the conditions ‘before’ and ‘after’ didn’t improve as much as the sham group at T1 in a Go-NoGo task (median reaction time). Regarding memory, participants in the condition ‘before’ didn’t improve as much as the sham group at T1 in non-verbal delayed recall (Rey-Osterrieth Complex Figure Test). Participants in the ‘during’ condition improved at T1 compared to the sham group in verbal delayed recall (Rey Auditory Verbal Learning Test). Discussion These preliminary results show that anodal tDCS over the left DLPFC can selectively modulate single functions from executive functions and memory. (1) Stimulation before and after an executive target task showed similar negative effects on inhibitory control, while stimulation during the target task did not show any effect on executive functioning. Yet, we only saw changes in one out of seven conducted executive tasks. Therefore, we cannot conclude a preferred timing of stimulation in relation to a working memory task aiming at the networks of executive functions through DLPFC stimulation. Interestingly, the only positive effects on cognition were seen with stimulation during the target task. (2) Stimulation during the target task had a positive impact on delayed recall in verbal memory, which is known to be hippocampus-dependent. Together with the negative effect on non-verbal delayed recall in the ‘before’ condition, these results indicate a wider, impact of tDCS on cognition, possibly related to electrode montage and subsequently activated brain networks.

P108. Effects of 10 Hz tACS on phonological language processing

Introduction A previous study ( Hartwigsen et al., 2010 ) has shown that 10 Hz rTMS of the left or right posterior inferior frontal gyrus (IFG) impaired performance in a phonological decision-making task. However, it is unclear whether the neurodisruptive effect of 10 Hz-rTMS is caused by entrainment of alpha-oscillations. To address this issue, the present study investigated the following questions: (1) Are alpha-oscillations in the IFG functionally relevant for phonological processing? (2) Can we enhance alpha activity in the IFG using 10 Hz tACS? and (3) Does enhancement of alpha activity cause behavioral disruption? Methods 24 right-handed, healthy participants (12 male, age range: 18–30 years, mean = 21.96, SD = 3.36) participated in the study. 9 mm2 circular sponge electrodes were placed over the bilateral IFG. In three separate sessions, 1 mA tACS at 10 Hz or 16.18 Hz or sham stimulation were applied for 20 min. Before and after stimulation, 5 min of resting state EEG was recorded. The phonological task required the subjects to indicate via button press whether highly frequent German nouns like ‘Zebra’ consisted of two or three syllables. In a simple control task, participants had to indicate whether an arrow pointed left or right to control for unspecific effects. Results (1) Stimulation was a significant predictor for decision speed in the phonological task (p = .02). Specifically, participants responded faster after 10 Hz relative to sham stimulation, but not after 16.18 Hz. (2) This effect was task specific as tACS did not significantly affect the control task (p = 0.43). (3) Participants had an increase in resting state alpha power (p = .004), which wasn’t modulated by stimulation (p = .70). (4) We found a significant event related desynchronization in the alpha band (p Conclusion The results show an improvement in a phonological word task after applying 10 Hz tACS over the bilateral IFG but not in simple motoric control task. This might be explained by a paradoxical facilitation effect, resulting in an ‘optimal’ level of noise for task processing ( Miniussi et al., 2013 ) or by inhibition of surrounding areas that might be competing for task resources. Since no specific effect on alpha oscillations could be found, further studies will therefore investigate effects of focal online stimulation.

Capacitance and forces for thick circular electrodes

Some new results are presented concerning the forces between two equal circular electrodes of finite thickness. For close electrodes different scenarios result, depending on the thickness and on the ratio of charges of the conductors. Attractive or repulsive forces can appear depending on the parameters and on the separation of the electrodes. The force between the electrodes can be non monotonic as a function of the distance and one or more equilibrium points can appear. A unified description of cylindrical systems using a high precision method based on a Galerkin expansion is given and we check our results with a quite accurate boundary element method (BEM).

A Micro EIT Sensor for Real-Time and Non-Destructive 3-D Cultivated Cell Imaging

A micro electrical impedance tomography (EIT) sensor with radially distributed planar electrodes was designed, characterized, and experimentally validated for real-time and non-destructive 3-D cultivated cell imaging. The 12-mm cylindrical sensor was consisted of 17 circular micro electrodes, including 16 sensing electrodes and a reference electrode. The sensor’s characteristics, i.e., dynamic range of measurement and sensitivity, were examined by finite element simulations and actual measurements. MCF-7 breast cancer cells were then cultivated to form the spherical aggregate and 3-D image reconstructions were performed on three solutions containing varying number and locations of cell aggregates. Furthermore, real-time imaging of cell-drug response between a MCF-7 cell aggregate and diluted Triton X-100 solution was carried out and the 3-D conductivity variation associated with this transient process was captured successfully and reconstructed in high accuracy. The simulation, 3-D cell aggregate imaging experiments and real-time reconstructions of cell-drug response suggest that the EIT-based micro sensor has the potential to study non-destructively and in real time the dynamic biological behavior of a 3-D cell culture system.

Influence of remote earth and impulse polarity on earthing systems by field measurement

There has been a vast vacuum in the literature on the importance of the location of remote earth carried out during impulse test on grounding systems using field measurements. Some published work show that the remote earth is installed surrounding the electrode under tests, whilst some have used separate remote earth, away from it. This work studies the impact of return electrode location on transient behaviour of the earthing electrode. The electrode under test is a single rod. Two types of remote earth configurations are used, a circular electrode with multiple rods surrounding the single rod, and one that is 80 m away from it. Impulse tests are conducted under both impulse polarities. Voltage and current traces are captured for a single rod, using two different types of remote earth configurations, with the impulse resistance measured as well. It has been established that the arrangement of the remote earth poses no influence on the test results. That said, higher oscillations of current traces and higher resistance values have been observed in negative impulse in comparison with positive impulse polarities.

Variable wide range of lens power and its improvement in a liquid-crystal lens using highly resistive films divided into two regions with different diameters

The variable range of lens power of a liquid-crystal (LC) lens driven by two voltages is discussed on the basis of calculated and experimental results. The LC lens has two electrodes, which are a circularly hole-patterned electrode and a circular electrode, in addition to a common electrode, and highly resistive transparent films. The variable range of lens power increases with increasing driving voltage applied across the circularly hole-patterned electrode and the common electrode, and with decreasing diameter of highly resistive films. However, the optical-phase retardation profile tends to deviate from a parabolic curve in these cases. As a method to improve the trade-off properties, the highly resistive film is divided into two regions with different diameters, where the sheet resistance of an outer film is larger than that of an inner one. The improved LC lens has a lens power that varies in a wide range, and it exhibits a good parabolic phase retardation profile.

Electrochemical Evaluations of Fractal Microelectrodes for Energy Efficient Neurostimulation

Advancements in microfabrication has enabled manufacturing of microscopic neurostimulation electrodes with smaller footprint than ever possible. The smaller electrodes can potentially reduce tissue damage and allow better spatial resolution for neural stimulation. Although electrodes of any shape can easily be fabricated, substantial effort have been focused on identification and characterization of new materials and surface morphology for efficient charge injection, while maintaining simple circular or rectangular Euclidean electrode geometries. In this work we provide a systematic electrochemical evaluation of charge injection capacities of serpentine and fractal-shaped platinum microelectrodes and compare their performance with traditional circular microelectrodes. Our findings indicate that the increase in electrode perimeter leads to an increase in maximum charge injection capacity. Furthermore, we found that the electrode geometry can have even more significant impact on electrode performance than having a larger perimeter for a given surface area. The fractal-shaped microelectrodes, despite having smaller perimeter than other designs, demonstrated superior charge injection capacity. Our results suggest that electrode design can significantly affect both Faradaic and non-Faradaic electrochemical processes, which may be optimized to enable a more energy efficient design for neurostimulation.

Circular electrodes to reduce the current variation of OTFTs with the drop-casted semiconducting layer

Circular organic thin film transistor (OTFT) structures are proposed to reduce the impact of variable grain alignment on the drive current of the polycrystalline organic thin film transistor (OTFT). As the circular structure is planar symmetric, the orientation of the grain cannot affect the drive current of the circular OTFT. Thus, circular electrodes expected to provide a lower variation. Top-gate, bottom-contact circular and conventional OTFTs with drop-casted polycrystalline 6,13-Bis(triisopropyl-silylethynyl) (TIPS)-Pentacene organic semiconducting layer (OSC) are fabricated to verify the theoretical variation reduction. The relative standard deviation (RSD), defined as the ratio of standard deviation and the average of drive current is used as the degree of variations in different structures. According to our fabrication result, circular transistors have a significantly lower variation (20% RSD), compared to the variation of conventional OTFTs (61% RSD).

Modeling shape selection of buckled dielectric elastomers

A dielectric elastomer whose edges are held fixed will buckle, given a sufficiently applied voltage, resulting in a nontrivial out-of-plane deformation. We study this situation numerically using a nonlinear elastic model which decouples two of the principal electrostatic stresses acting on an elastomer: normal pressure due to the mutual attraction of oppositely charged electrodes and tangential shear (“fringing”) due to repulsion of like charges at the electrode edges. These enter via physically simplified boundary conditions that are applied in a fixed reference domain using a nondimensional approach. The method is valid for small to moderate strains and is straightforward to implement in a generic nonlinear elasticity code. We validate the model by directly comparing the simulated equilibrium shapes with the experiment. For circular electrodes which buckle axisymetrically, the shape of the deflection profile is captured. Annular electrodes of different widths produce azimuthal ripples with wavelengths that match our simulations. In this case, it is essential to compute multiple equilibria because the first model solution obtained by the nonlinear solver (Newton's method) is often not the energetically favored state. We address this using a numerical technique known as “deflation.” Finally, we observe the large number of different solutions that may be obtained for the case of a long rectangular strip.

Field emission characterization of in situ deposited gold nanocones with variable cone densities

For the fabrication of field emitter cathodes with metallic nanocones, an in situ fabrication technique based on electrodeposition in an ion track etched polymer template was used. Three samples with nanocones made of gold and different cone densities were deposited on a circular electrode with a diameter of 2.5 mm, using templates with pore density of 6 × 104, 4 × 105, and 1 × 106 cones/cm2. The cones had a height of 24 μm, a base diameter between 3 and 3.75 μm, and a tip diameter below 500 nm. Integral field emission measurements revealed onset fields of down to 3.1 V/μm and average field enhancement factors of up to 1240. For one sample, the maximum emission current from the cathode reached 142.2 μA at an applied voltage of 338 V between cathode and extraction grid, which had a distance of 50 μm. To investigate the stability of the field emission current, cumulative long-term measurements were performed for over 50 h. A stable emission current of (31.0 ± 1.3) μA at an average applied voltage of 290 V (E = 5.8 V/μm) was observed. For currents above 100 μA, a decrease of the current and therefore a degradation of the emitter structures occurred.

TMV-Based Adapter Templates for Enhanced Enzyme Loading in Biosensor Applications.

Nanotubular tobacco mosaic virus (TMV) particles and RNA-free lower-order coat protein (CP) aggregates have been employed as enzyme carriers in different diagnostic layouts and compared for their influence on biosensor performance. In the following, we describe a label-free electrochemical biosensor for improved glucose detection by use of TMV adapters and the enzyme glucose oxidase (GOD). A specific and efficient immobilization of streptavidin-conjugated GOD ([SA]-GOD) complexes on biotinylated TMV nanotubes or CP aggregates was achieved via bioaffinity binding. Glucose sensors with adsorptively immobilized [SA]-GOD, and with [SA]-GOD cross-linked with glutardialdehyde, respectively, were tested in parallel on the same sensor chip. Comparison of these sensors revealed that TMV adapters enhanced the amperometric glucose detection remarkably, conveying highest sensitivity, an extended linear detection range and fastest response times. These results underline a great potential of an integration of virus/biomolecule hybrids with electronic transducers for applications in biosensorics and biochips. Here, we describe the fabrication and use of amperometric sensor chips combining an array of circular Pt electrodes, their loading with GOD-modified TMV nanotubes (and other GOD immobilization methods), and the subsequent investigations of the sensor performance.

Tunable Negative Differential Resistance in MISIM Tunnel Diodes Structure With Concentric Circular Electrodes Controlled by Designed Substrate Bias

The tunable negative differential resistance (NDR) characteristics of metal–insulator–semiconductor–insulator–metal (MISIM) tunnel diodes (TDs) structure with thin oxide were observed by biasing the substrate simultaneously with one of the TDs under designed voltage drops ( $\Delta \text{V}$ ). An inner circular electrode TD surrounded by a ring-shape electrode TD gate pattern was adopted. The NDR region can be adjusted by varying the $\Delta \text{V}$ between the inner TD and the body. Not only the peak-to-valley current ratio (PVCR) but also the voltage range where NDR occurs can be controlled. It is supposed that the injected electrons and the inversion charges increase and decrease with negative bias, respectively, for the MIS(p) TD and play an important role in this observation. Meanwhile, the asymmetry of inner gate and ring gate enhances the coupling efficiency at reverse bias region. In this paper, the PVCR can be tuned to more than two orders and the voltage of the NDR region can be shifted to larger than 1 V. The tunable NDR characteristic of MISIM provides a possible application of MIS TD.

Electric potential profile created by end electrodes in a magnetized rf discharge plasma

The problem of generating a stationary electric field in a magnetized radio-frequency discharge (rf) plasma is studied experimentally. Helmholtz coils produce magnetic field in a cylindrical vacuum chamber with diameter of 85.6 cm and length of 220 cm. RF discharge is generated at a frequency of ∼ 5 MHz. The rf power absorbed by plasma lies in the range 0.5-1.5 kW. Electrodes defining a negative potential are placed at the ends of the chamber. Two pairs of circular flat electrodes with diameter of 5.5 and 45 cm are investigated. The working gas is argon. Radial profiles of electron density and temperature are obtained. Radial profile of the plasma potential is investigated, as well as the dependence of plasma potential on the voltage applied to the end-electrodes.

Geometric optimisation of electrohydrodynamic fluid flows for enhanced biosensing

The removal of non-specific binding on the sensor surface represents a major challenge for rapid and sensitive biosensing. The stimulation of an electrohydrodynamic (EHD) fluid flow in proximity to the biosensor surface can improve sensor performance. The EHD fluid flow is depending on the geometry of electrodes. Here, the effect of electrode diameter and spacing of asymmetric circular electrodes is investigated for the capability to stimulate fluid flow and capture model beads and protein biomarker. Six geometries with diameters of 30–1000μm and spacing of 200–1500μm were systematically studied. Capture of target beads in excess of non-target beads showed higher target bead capture with increase in electrode diameter. The target bead capture was 4× improved and displacement of non-target reduced by factor 2. The electrode with the highest bead capture was then used to establish an immunoassay for detection of novel cancer immunotherapy biomarker CD28 fortified in buffer and fetal bovine serum. The EHD parameters for optimal CD28 capture were different to the bead capture parameters. This indicated that, depending on the binding strength of target to affinity tag, the EHD parameters could be tailored to provide ideal capture conditions. The use of EHD significantly reduced the assay time by 92.4%, removed non-target binding by a factor of 3.5 compared to static incubation, and was sensitive to detect as low as 20pgmL−1 CD28. In a proof-of-concept study, the potential of the EHD-assisted immunoassay for point of care application was demonstrated using a simple naked eye read-out.