Dielectrophoresis (DEP) and electrorotation (ROT) are two electrokinetic phenomena exploiting nonuniform electric fields to exert a force or torque on biological particles suspended in liquid media. ...They are widely used in lab-on-chip devices for the manipulation, trapping, separation, and characterization of cells, microorganisms, and other particles. The DEP force and ROT torque depend on the respective polarizabilities of the particle and medium, which in turn depend on their dielectric properties and on the field frequency. In this work, we present a new software, MyDEP, which implements several particle models based on concentric shells with adjustable dielectric properties. This tool enables the study of the variation in DEP and ROT spectra according to different parameters, such as the field frequency and medium conductivity. Such predictions of particle behavior are very useful for choosing appropriate parameters in DEP experiments. The software also enables the study of the homogenized properties of spherical or ellipsoidal multishell particles and provides a database containing published cell properties. Equivalent electrical conductivity and relative permittivity of the cell alone and in suspension can be calculated. The software also offers the ability to create graphs of the evolution of the crossover frequencies with the electric field frequency. These graphs can be directly exported from the software.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this work, we propose a novel functionalized carbon nanotube (f-CNT) supporting nanoporous cauliflower-like Pd nanostructures (PdNS) as an enzyme-free interface for glucose electrooxidation ...reaction (GOR) in a neutral medium (pH 7.4). The novelty resides in preparing the PdNS/f-CNT biomimetic nanocatalyst using a cost-effective and straightforward method, which consists of drop-casting well-dispersed f-CNTs over the Screen-printed carbon electrode (SPCE) surface, followed by the electrodeposition of PdNS. Several parameters affecting the morphology, structure, and catalytic properties toward the GOR of the PdNS catalyst, such as the PdCl
precursor concentration and electrodeposition conditions, were investigated during this work. The electrochemical behavior of the PdNS/f-CNT/SPCE toward GOR was investigated through Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and amperometry. There was also a good correlation between the morphology, structure, and electrocatalytic activity of the PdNS electrocatalyst. Furthermore, the LSV response and potential-pH diagram for the palladium-water system have enabled the proposal for a mechanism of this GOR. The proposed mechanism would be beneficial, as the basis, to achieve the highest catalytic activity by selecting the suitable potential range. Under the optimal conditions, the PdNS/f-CNT/SPCE-based biomimetic sensor presented a wide linear range (1-41 mM) with a sensitivity of 9.3 µA cm
mM
and a detection limit of 95 µM (S/N = 3) toward glucose at a detection potential of +300 mV vs. a saturated calomel electrode. Furthermore, because of the fascinating features such as fast response, low cost, reusability, and poison-free characteristics, the as-proposed electrocatalyst could be of great interest in both detection systems (glucose sensors) and direct glucose fuel cells.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A novel approach allowing the production of electrical energy by an advanced oxidation process is proposed to eliminate organic micropollutants (MPs) in wastewaters. This approach is based on ...associating the Galvano–Fenton process to the generation of electrical power. In the previous studies describing the Galvano–Fenton (GF) process, iron was directly coupled to a metal of more positive potential to ensure degradation of organic pollutants without any possibility of producing electrical energy. In this new approach, the Galvano–Fenton process is constructed as an electrochemical cell with an external circuit allowing recovering electrons exchanged during the process. In this study, Malachite Green (MG) dye was used as a model of organic pollutant. Simultaneous MG degradation and electrical energy production with the GF method were investigated in batch process. The investigation of various design parameters emphasis that utilization of copper as a low-cost cathode material in the galvanic couple, provides the best treatment and electrical production performances. Moreover, these performances are improved by increasing the surface area of the cathode. The present work reveals that the GF process has a potential to provide an electrical power density of about 200 W m−2. These interesting performances indicate that this novel Energy-from-Waste strategy of the GF process could serve as an ecological solution for wastewater treatment.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This paper describes a comprehensive analysis of the geometrical parameters influencing the sensitivity of a coplanar electrode layout for electrical impedance flow cytometry. The designs presented ...in this work have been simulated, fabricated, and tested. 3D finite element method was applied to simulate and improve the sensitivity of the coplanar designs for two spacings between electrodes. The proposed model uses conditional expressions to define spatially dependent material properties. The vertical and lateral sensitivities were evaluated for all the designs. The experimental results obtained with polystyrene beads show good agreement with the simulations. Precentering particles with dielectrophoresis allowed to control their position in the microchannel. The optimized designs are envisioned to be used for sizing and characterizing particles from single cells to cell aggregates.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The development of high-performance anode materials is one of the greatest challenges for the practical implementation of Microbial Fuel Cell (MFC) technology. Copper (Cu) has a much higher ...electrical conductivity than carbon-based materials usually used as anodes in MFCs. However, it is an unsuitable anode material, in raw state, for MFC application due to its corrosion and its toxicity to microorganisms. In this paper, we report the development of a Cu anode material coated with a corrosion-resistant composite made of Polydimethylsiloxane (PDMS) doped with carbon nanofiber (CNF). The surface modification method was optimized for improving the interfacial electron transfer of Cu anodes for use in MFCs. Characterization of CNF-PDMS composites doped at different weight ratios demonstrated that the best electrical conductivity and electrochemical properties are obtained at 8% weight ratio of CNF/PDMS mixture. Electrochemical characterization showed that the corrosion rate of Cu electrode in acidified solution decreased from (17 ± 6) × 10
μm y
to 93 ± 23 μm y
after CNF-PDMS coating. The performance of Cu anodes coated with different layer thicknesses of CNF-PDMS (250 µm, 500 µm, and 1000 µm), was evaluated in MFC. The highest power density of 70 ± 8 mW m
obtained with 500 µm CNF-PDMS was about 8-times higher and more stable than that obtained through galvanic corrosion of unmodified Cu. Consequently, the followed process improves the performance of Cu anode for MFC applications.
Bioelectrocatalytic carbon nanotube based pellets comprising redox enzymes were directly integrated in a newly conceived flow-through fuel cell. Porous electrodes and a separating cellulose membrane ...were housed in a glucose/oxygen biofuel cell design with inlets and outlets allowing the flow of electrolyte through the entire fuel cell. Different flow setups were tested and the optimized single cell setup, exploiting only 5 mmol L–1 glucose, showed an open circuit voltage (OCV) of 0.663 V and provided 1.03 ± 0.05 mW at 0.34 V. Furthermore, different charge/discharge cycles at 500 Ω and 3 kΩ were applied to optimize long-term stability leading to 3.6 J (1 mW h) of produced electrical energy after 48 h. Under continuous discharge at 6 kΩ, about 0.7 mW h could be produced after a 24 h period. The biofuel cell design further allows a convenient assembly of several glucose biofuel cells in reduced volumes and their connection in parallel or in series. The configuration of two biofuel cells connected in series showed an OCV of 1.35 V and provided 1.82 ± 0.09 mW at 0.675 V, and when connected in parallel, showed an OCV of 0.669 V and provided 1.75 ± 0.09 mW at 0.381 V. The presented design is conceived to stack an unlimited amount of biofuel cells to reach the necessary voltage and power for portable electronic devices without the need for step-up converters or energy managing systems.
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IJS, KILJ, NUK, PNG, UL, UM
This research sought to enhance the efficiency and biocompatibility of anodes in bioelectrochemical systems (BESs) such as microbial fuel cells (MFCs), with an aim toward large-scale, real-world ...applications. The study focused on the effects of acid-heat treatment and chemical modification of three-dimensional porous pristine carbon felt (CF) on power generation. Different treatments were applied to the pristine CF, including coating with carbon nanofibers (CNFs) dispersed using dodecylbenzene sulfonate (SDBS) surfactant and biopolymer chitosan (CS). These processes were expected to improve the hydrophilicity, reduce the internal resistance, and increase the electrochemically active surface area of CF anodes. A high-resolution scanning electron microscopy (HR-SEM) analysis confirmed successful CNF coating. An electrochemical analysis showed improved conductivity and charge transfer toward Fe(CN)6
redox probe with treated anodes. When used in an air cathode single-chamber MFC system, the untreated CF facilitated quicker electroactive biofilm growth and reached a maximum power output density of 3.4 W m
, with an open-circuit potential of 550 mV. Despite a reduction in charge transfer resistance (R
) with the treated CF anodes, the power densities remained unchanged. These results suggest that untreated CF anodes could be most promising for enhancing power output in BESs, offering a cost-effective solution for large-scale MFC applications.
This study introduces the utilization of self-powered microbial fuel cell (MFC)-based biosensors for the detection of biotoxicity in wastewater. Current MFC-based biosensors lack specificity in ...distinguishing between different pollutants. To address this limitation, a novel approach is introduced, capitalizing on the adaptive capabilities of anodic biofilms. By acclimating these biofilms to specific pollutants, an enhancement in the selectivity of MFC biosensors is achieved. Notably, electrochemically active bacteria (EAB) were cultivated on 3D porous carbon felt with and without a model toxicant (target analyte), resulting in the development of toxicant-resistant anodic biofilms. The model toxicants, Pb2+ ions and the antibiotic neomycin sulfate (NS), were deployed at a concentration of 1 mg L−1 during MFC operation. The influence of toxicity on biofilm growth and power production was investigated through polarization and power density curves. Concurrently, the electrochemical activity of both non-adapted and toxicity-adapted biofilms was investigated using cyclic voltammetry. Upon maturation and attainment of peak powers, the MFC reactors were evaluated individually as self-powered biosensors for pollutant detection in fresh wastewater, employing the external resistor (ER) mode. The selected ER, corresponding to the maximum power output, was positioned between the cathode and anode of each MFC, enabling output signal tracking through a data logging system. Subsequent exposure of mature biofilm-based MFC biosensors to various concentrations of the targeted toxicants revealed that non-adapted mature biofilms generated similar current–time profiles for both toxicity models, whereas toxicity-adapted biofilms produced distinctive current–time profiles. Accordingly, these results suggested that merely by adapting the anodic biofilm to the targeted toxicity, distinct and identifiable current–time profiles can be created. Furthermore, these toxicity-adapted and non-adapted biofilms can be employed to selectively detect the pollutant via the differential measurement of electrical signals. This differentiation offers a promising avenue for selective pollutant detection. To the best of our current knowledge, this approach, which harnesses the natural adaptability of biofilms for enhanced sensor selectivity, represents a pioneering effort in the realm of MFC-based biosensing.
We present a microfluidic platform allowing dielectrophoresis‐assisted formation of cell aggregates of controlled size and composition under flow conditions. When specific experimental conditions are ...met, negative dielectrophoresis allows efficient concentration of cells towards electric field minima and subsequent aggregation. This bottom‐up assembly strategy offers several advantages with respect to the targeted application: first, dielectrophoresis offers precise control of spatial cell organization, which can be adjusted by optimizing electrode design. Then, it could contribute to accelerate the establishment of cell‐cell interactions by favoring close contact between neighboring cells. The trapping geometry of our chip is composed of eight electrodes arranged in a circle. Several parameters have been tested in simulations to find the best configurations for trapping in flow. Those configurations have been tested experimentally with both polystyrene beads and human embryonic kidney cells. The final design and experimental setup have been optimized to trap cells and release the created aggregates on demand.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Herein, the authors propose a miniaturized glucose/O
n-EFC based on a new direct electron transfer. The anode is a screen-printed carbon electrode (SPCE) modified with functionalized carbon nanotubes ...(f-CNTs) and cauliflower-like PdAu nanostructures (PdAuNS). The PdAuNS/f-CNT biomimetic nanocatalyst was prepared using a cost-effective and straightforward method, which consisted of drop-casting well-dispersed f-CNTs over the SPCE surface before PdAuNS electrodeposition. This enzyme-free interface was used for glucose electrooxidation at neutral medium (pH 7.4). The electrochemical behaviour of the PdAuNS/f-CNT/SPCE was investigated using cyclic voltammetry, linear sweep voltammetry, and amperometry. Several parameters were optimized and discussed, including the metal precursor concentration (HAuCl
, PdCl
) and the electrodeposition conditions. The cathode for oxygen electroreduction is an air-cathode which is composed of Pt-coated carbon cloth. The electrochemical performances of the anode and the cathode were evaluated separately for glucose oxidation and oxygen reduction, respectively. Both electrodes were then assembled in a membrane-less single chamber n-EFC with an innovative architecture. Electrical characterization of the n-EFC supplied with a neutral buffered solution containing 20 mM glucose showed a maximal power output of 129 ± 11 μW cm
, a current density of 600 ± 39 μA cm
with a cell voltage of 0.35 V, and an open circuit potential of 0.56 V. The proposed electrocatalyst possesses several advantages such as fast response, low cost, reusability, poison-free characteristics, and good stability. Hence, glucose/O
n-EFC could be of great interest in direct glucose fuel cell applications (e.g., powering mountable/implantable biomedical micro-devices running at low electrical power supply) or in self-powered biosensing.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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