Fig 6
Dependence of the fluorescence intensity of Adriamycin and porphyrin sulfonate on the amount of FeCl 3 added into solution.
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One of the plausible reactions occurring during high–voltage pulses, which are used to electroporate the cells, is the oxidation of the metal ions of the anode resulting in the dissolution of the anode. In the case of the anode made from stainless–steel, which is one of the most popular electrode materials, iron ions (Fe2+ and Fe3+) are released fr...
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... SK, can be converted by iron ions into nonfluorescent forms [19], [20]. In the presence of 0.5-mM Fe 2+ , the fluorescence of calcein was suppressed by >80% (Rodaite-Riseviciene and Saulis, unpublished data). In the presence of 1-mM Fe 3+ , fluorescence of meso-tetrakis (4-sulfonatophenyl) porphyrin was totally suppressed, and Adriamycin by 30% (Fig. 6). Quenching of the fluorescence of calcein was observed, when high-voltage electric pulses were used for transdermal drug delivery ...
Citations
... High voltages may potentially affect not only the cell membranes but also the added iron-containing compounds. The compounds could undergo reduction on the electrodes to a lower oxidation state (+II) and thus decrease the amount of electricity applied directly to the membrane [60,61]. Iron (III) citrate has been proven to decompose with the release of carbon dioxide when the iron ion is reduced to the second oxidation state [62]. ...
These authors contributed equally to this work. Abstract: Colon cancer (CC) management includes surgery, radio-and chemotherapy based on treatment with 5-fluorouracil (5-FU) or its derivatives. However, its application is limited to low-grade carcinomas. Thus, much research has been conducted to introduce new techniques and drugs to the therapy. CC mostly affects older people suffering from cardiac diseases, where iron compounds are commonly used. Ferric citrate and iron (III)-EDTA complexes have proven to be effective in colon cancer in vitro. This study aimed to determine the potency and action of iron-containing compounds in colon cancer treatment by chemo-and electrochemotherapy in both nano-and microsecond protocols. The viability of the cells was assessed after standalone iron (III) citrate and iron (III)-EDTA incubation. Both compounds were also assessed with 5-FU to determine the combination index. Additionally, frataxin expression was taken as the quantitative response to the exposition of iron compounds. Each of the substances exhibited a cytotoxic effect on the LoVo cell line. Electroporation with standalone drugs revealed the potency of 5-FU and iron(III)-EDTA in CC treatment. The combination of 5-FU with iron(III)-EDTA acted synergistically, increasing the viability of the cells in the nanosecond electrochemotherapy protocol. Iron(III)-EDTA decreased the frataxin expression, thus inducing ferroptosis. Iron(III) citrate induced the progression of cancer; therefore, it should not be considered as a potential therapeutic option. The relatively low stability of iron(III) citrate leads to the delivery of citrate anions to cancer cells, which could increase the Krebs cycle rate and promote progression.
... Nanosecond pulsed electric field (nsPEF) protocols are a natural evolution of electroporation due to the benefits the ultra-short pulses can offer. Shorter pulses reduce muscle excitation and potential pain (Miklavčič et al., 2005), minimize oxidation damage (Rodaite- Riseviciene et al., 2014;Mahnič-Kalamiza and Miklavčič, 2020), improve treatment homogeneity due to higher frequency components (Bhonsle et al., 2015) and offer a lot more flexibility in parametric protocol design and input energy delivery (Schoenbach et al., 2009). It's particularly important in the context of non-invasive ECT (e.g., using parallel plate electrodes) since the top and bottom of the tumor are not in direct contact with the electrode and thus significantly lower electric field is induced in the volume, which may result in tumor regrowth . ...
Drug delivery using nanosecond pulsed electric fields is a new branch of electroporation-based treatments, which potentially can substitute European standard operating procedures for electrochemotherapy. In this work, for the first time, we characterize the effects of ultra-fast repetition frequency (1–2.5 MHz) nanosecond pulses (5–9 kV/ cm, 200 and 400 ns) in the context of nano-electrochemotherapy with calcium. Additionally, we investigate the feasibility of bipolar symmetric (↑200 ns + ↓200 ns) and asymmetric (↑200 ns + ↓400 ns) nanosecond protocols for calcium delivery. The effects of bipolar cancellation and the influence of interphase delay (200 ns) are overviewed. Human lung cancer cell lines A549 and H69AR were used as a model. It was shown that unipolar pulses delivered at high frequency are effective for electrochemotherapy with a significant improvement in ef- ficiency when the delay between separate pulses is reduced. Bipolar symmetric pulses trigger the cancellation phenomenon limiting applications for drug delivery and can be compensated by the asymmetry of the pulse (↑200 ns + ↓400 ns or ↑400 ns + ↓200 ns). The results of this study can be successfully used to derive a new generation of nsPEF protocols for successful electrochemotherapy treatments.
... Electrochemical reactions occur when employing conductive electrodes, which produce metal ions and free radicals on an electrode's surface [29][30][31], leading to a shorter electrode lifespan. Moreover, the byproducts of these electrochemical reactions may initiate secondary chemical reactions that precipitate pollutant production [32,33]. Other limitations of this method are its high energy consumption and safety concerns regarding high voltage and current utilization [34]. ...
A non-chemical solution is needed to control biofilms in water and wastewater treatment systems. High-frequency alternating electric field application offers an alternative approach that does not involve undesired electrode surface reactions. However, the effect of high-frequency alternating electric fields on bacterial cells in the attached-growth mode remains unexplored. This study investigated the impact of such fields on two stages of the biofilm development process: the initial adhesion phase (stage 1) and the early development phase (stage 2). Experiments were conducted using Escherichia coli and Pseudomonas aeruginosa in a three-channel flow cell exposed to alternating electric fields (3.05 V/cm, 20 MHz). The primary outcome of this study demonstrated that alternating electric fields decreased adhered cell numbers at both stages due to their inhibitory effect on growth. The alternating electric fields also triggered cell detachment after the initial attachment stage but not in mature biofilms. Interestingly, despite a reduction in cell counts, the amount of total biofilm biomass remained unaffected, which was likely due to increased cell size via cell elongation compensating for the decrease in numbers. No synergistic effects with respect to hydrodynamic forces were observed. These findings highlight the potential applicability of alternating electric fields to biofilm control and provide implications for water and wastewater engineering applications.
... For biomedical applications two different types of stainless steel with low carbon content and different compositions are in use, 304L and 316L stainless steel. The applications range from orthopedic implants and prosthetics 92,96 , cardiovascular stents 97 to stimulation electrodes for bone healing 98 or electrode materials in the field of electroporation 99 . However, due to corrosion and therefore release of Ni-ions stainless steel is only approved for short term implantation. ...
... This phenomenon suggested that the electrochemical reactions around the ground electrodes were more intense in the present study. It is widely accepted that reactions on the anode surface are more severe than those on the cathode surface when high voltage impulses are applied [19][20][21]. In the present study, the pulse-generating system produced negative impulses, as can be seen from Figure 4, which made the ground electrodes effectively the anode. ...
Investigation of pulsed electric field (PEF) treatment of yeast at 20 kV/cm using chambers with BaTiO3 dielectric layers was conducted in this study. The sterile rate as well as concentrations of metallic ions and hydroxyl radicals were measured to assess the PEF performance. The results indicated that generation of metallic ions could be reduced by 90%. However, a much higher field strength would be required for satisfactory sterilization due to the Maxwell-Wagner field relaxation, and reactions between the dielectric barriers and liquid could also occur. It was also proven that the continuous presence of a sufficient electric field is the main factor that inactivates the microorganism.
... The application of PEFs for LCB pretreatment is still in its initial stages. Furthermore, the electrode reaction can cause the production of toxic chemicals (e.g., H 2 O 2 , HCl, and HClO) and electrolysis of water, resulting in changes in the chemical properties (e.g., pH and conductivity) of the solution near the surface of the electrodes (Rodaitė-Riševičienė et al., 2014). Further research is needed to clarify the exact mechanism of PEF technologies and optimization of different factors, such as the design of the chamber, types of material used for electrode manufacturing, and electrical conditions (pulse duration, energy input, and polarity) for LCB pretreatment (Golberg et al., 2016). ...
The inherent recalcitrance of lignocellulosic biomass is a significant barrier to efficient lignocellulosic biorefinery owing to its complex structure and the presence of inhibitory components, primarily lignin. Efficient biomass pretreatment strategies are crucial for the fragmentation of lignocellulosic biocomponents, increasing the surface area and solubility of cellulose fibers, and removing or extracting lignin. Conventional pretreatment methods have several disadvantages, such as high operational costs, equipment corrosion, and the generation of toxic byproducts and effluents. In recent years, many emerging single-step, multi-step, and/or combined physicochemical pretreatment regimes have been developed, which are simpler in operation, more economical, and environmentally friendly. Furthermore, many of these combined physicochemical methods improve biomass bioaccessibility and effectively fractionate ∼96% of lignocellulosic biocomponents into cellulose, hemicellulose, and lignin, thereby allowing for highly efficient lignocellulose bioconversion. This review critically discusses the emerging physicochemical pretreatment methods for efficient lignocellulose bioconversion for biofuel production to address the global energy crisis.
... La coagulación, después de la incorporación de una sal al agua, introduce cationes metálicos, mientras que la electrocoagulación crea esos mismos iones por la corriente eléctrica que pasa por electrodos. Los cationes polivalentes comunes a ambos forman un acuoión que inicia la desprotonación espontánea sucesiva hasta formar especies monoméricas, hidroxo complejos con iones hidróxido y especies poliméricas [20], [21] . Las reacciones que normalmente se reportan son con aluminio o hierro [20] : (1) Los M(OH)n producidos, donde M = Fe o Al, inducen sorción, coprecipitación o atracción electrostática se-guida de la coagulación per se [22], [23] . ...
... Los cationes polivalentes comunes a ambos forman un acuoión que inicia la desprotonación espontánea sucesiva hasta formar especies monoméricas, hidroxo complejos con iones hidróxido y especies poliméricas [20], [21] . Las reacciones que normalmente se reportan son con aluminio o hierro [20] : (1) Los M(OH)n producidos, donde M = Fe o Al, inducen sorción, coprecipitación o atracción electrostática se-guida de la coagulación per se [22], [23] . La cantidad de lodo que precipita es reducida debido a que no se requiere el suministro adicional de químicos [24], [25] . ...
... La cantidad de lodo que precipita es reducida debido a que no se requiere el suministro adicional de químicos [24], [25] . Los iones de hierro pueden ser liberados equivalentemente desde un electrodo de acero inoxidable como ferroso (Fe 2+ ) o férrico (Fe 3+ ) [20] . ...
La presencia de metales pesados en el agua para consumo humano tiene su origen en las actividades antropogénicas o en procesos naturales. Los seres humanos pueden estar expuestos a 23 de estos minerales que son tóxicos en dosis grandes o pequeñas y pueden afectar diversos órganos, desencadenar enfermedades como Parkinson y Alzheimer por acumulación progresiva o provocar cáncer. Los métodos de tratamiento pretenden abatir la concentración de metales pesados en matrices acuosas, al mismo tiempo que se manifiestan como una solución. La tecnología electroquímica denominada electrocoagulación ha sido usada con éxito para remover cadmio, cobre, cromo, manganeso, mercurio, níquel y cinc en el laboratorio sin descartar, aunque con menor frecuencia, la escala piloto. Se revisaron artículos sobre investigaciones en este tema desarrolladas entre 2015 y 2022 en diversos países y se concluye que electrocoagulación tiene el potencial para propiciar un uso exitoso en plantas de tratamiento pequeñas debido a sus ventajas, entre ellas que no requiere del suministro suplementario de algún compuesto químico en su concepción más básica, genera menor cantidad de lodos, la selección de los materiales electródicos y el acomodo dentro de la celda son relevantes para lograr resultados superiores y el costo energético razonable por cada metro cúbico de agua procesada.
... Several consequences of this process can be important for studying and/or using the cell electroporation phenomenon. Metal ions released from the electrodes can: (i) affect physiological processes [13]; (ii) change the pH of the medium [21]; (iii) reduce cell viability [15,21]; (iv) change the electric conductivity of the medium [21,22]; (v) increase the roughness of the anode surface [23]; (vi) build up complexes with various molecules, including proteins, DNA, and RNR [17,24]; as well as (vii) quench the fluorescence of fluorophores [21,25]. ...
... Several consequences of this process can be important for studying and/or using the cell electroporation phenomenon. Metal ions released from the electrodes can: (i) affect physiological processes [13]; (ii) change the pH of the medium [21]; (iii) reduce cell viability [15,21]; (iv) change the electric conductivity of the medium [21,22]; (v) increase the roughness of the anode surface [23]; (vi) build up complexes with various molecules, including proteins, DNA, and RNR [17,24]; as well as (vii) quench the fluorescence of fluorophores [21,25]. ...
... Several consequences of this process can be important for studying and/or using the cell electroporation phenomenon. Metal ions released from the electrodes can: (i) affect physiological processes [13]; (ii) change the pH of the medium [21]; (iii) reduce cell viability [15,21]; (iv) change the electric conductivity of the medium [21,22]; (v) increase the roughness of the anode surface [23]; (vi) build up complexes with various molecules, including proteins, DNA, and RNR [17,24]; as well as (vii) quench the fluorescence of fluorophores [21,25]. ...
High-voltage pulses applied to a cell suspension cause not only cell membrane permeabilization, but a variety of electrolysis reactions to also occur at the electrode–solution interfaces. Here, the cytotoxicity of a culture medium treated by a single electric pulse and the role of the iron ions in this cytotoxicity were studied in vitro. The experiments were carried out on mouse hepatoma MH-22A, rat glioma C6, and Chinese hamster ovary cells. The cell culture medium treated with a high-voltage pulse was highly cytotoxic. All cells died in the medium treated by a single electric pulse with a duration of 2 ms and an amplitude of just 0.2 kV/cm. The medium treated with a shorter pulse was less cytotoxic. The cell viability was inversely proportional to the amount of electric charge that flowed through the solution. The amount of iron ions released from the stainless steel anode (> 0.5 mM) was enough to reduce cell viability. However, iron ions were not the sole reason of cell death. To kill all MH-22A and CHO cells, the concentration of Fe3+ ions in a medium of more than 2 mM was required.
... The second way of ROS formation is the direct burst of ROS at the surface of the electrodes during the PEF treatment [247]. The extent of ROS formation also depends on the electrode material [248,249]. During PEF treatment cell suspension is exposed to a strong electric current that passes the solution. ...
... Longer, microsecond range electrical pulses lead to electrolysis and changes in pH and thus the generation of free radicals [248,249]. The electrode material also matters for the quantity of ROS generated at the electrode surface. ...
... Higher electropermeabilization efficacy comes with higher ROS formation, especially when copper electrodes are used in comparison to aluminum and steel electrodes applying both nanosecond and microsecond pulses range. However, not only the pH changes but also metal ion release proved to play a significant role in ROS formation [248,249]. For example, the formation of H 2 O 2 was proposed to happen through nsPEF electrochemical effect on the electrodes. ...
Currently, microbial biofilms have been the cause of a wide variety of infections in the human body, reaching 80% of all bacterial and fungal infections. The biofilms present specific properties that increase the resistance to antimicrobial treatments. Thus, the development of new approaches is urgent, and antimicrobial photodynamic therapy (aPDT) has been shown as a promising candidate. aPDT involves a synergic association of a photosensitizer (PS), molecular oxygen and visible light, producing highly reactive oxygen species (ROS) that cause the oxidation of several cellular components. This therapy attacks many components of the biofilm, including proteins, lipids, and nucleic acids present within the biofilm matrix; causing inhibition even in the cells that are inside the extracellular polymeric substance (EPS). Recent advances in designing new PSs to increase the production of ROS and the combination of aPDT with other therapies, especially pulsed electric fields (PEF), have contributed to enhanced biofilm inhibition. The PEF has proven to have antimicrobial effect once it is known that extensive chemical reactions occur when electric fields are applied. This type of treatment kills microorganisms not only due to membrane rupture but also due to the formation of reactive compounds including free oxygen, hydrogen, hydroxyl and hydroperoxyl radicals. So, this review aims to show the progress of aPDT and PEF against the biofilms, suggesting that the association of both methods can potentiate their effects and overcome biofilm infections.
... This was confirmed by the detection, characterization, and quantification of Al in aggregates, reproducibly found in several solutions subjected to millisecond pulses. Several reports have studied the emissions of metallic ions, mainly as undesirable modifications of the experimental conditions and detrimental effects on target cells [57][58][59][60][61][62] . In particular, one group has observed that electric pulses induced significant precipitation of biological macromolecules (DNA, RNA and proteins) in electroporation using millisecond pulses 59 . ...
Gene electrotransfer is an attractive method of non-viral gene delivery. However, the mechanism of DNA penetration across the plasma membrane is widely discussed. To explore this process for even larger structures, like viruses, we applied various combinations of short/long and high/low-amplitude electric pulses to L929 cells, mixed with a human adenovirus vector expressing GFP. We observed a transgene expression increase, both in the number of GFP-converted cells and GFP levels, when we added a low-voltage/millisecond-pulse treatment to the adenovirus/cell mixture. This increase, reflecting enhanced virus penetration, was proportional to the applied electric field amplitude and pulse number, but was not associated with membrane permeabilization, nor to direct cell modifications. We demonstrated that this effect is mainly due to adenovirus particle interactions with aggregated aluminum particles released from energized electrodes. Indeed, after centrifugation of the pulsed viral suspension and later on addition to cells, the activity was found mainly associated with the aluminum aggregates concentrated in the lower fraction and was proportional to generated quantities. Overall, this work focused on the use of electrotransfer to facilitate the adenovirus entry into cell, demonstrating that modifications of the penetrating agent can be more important than modifications of the target cell for transfer efficacy.
