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1.
J Mater Chem B ; 12(18): 4409-4426, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38630533

ABSTRACT

Spinal cord injury (SCI) usually induces profound microvascular dysfunction. It disrupts the integrity of the blood-spinal cord barrier (BSCB), which could trigger a cascade of secondary pathological events that manifest as neuronal apoptosis and axonal demyelination. These events can further lead to irreversible neurological impairments. Thus, reducing the permeability of the BSCB and maintaining its substructural integrity are essential to promote neuronal survival following SCI. Tetramethylpyrazine (TMP) has emerged as a potential protective agent for treating the BSCB after SCI. However, its therapeutic potential is hindered by challenges in the administration route and suboptimal bioavailability, leading to attenuated clinical outcomes. To address this challenge, traditional Chinese medicine, TMP, was used in this study to construct a drug-loaded electroconductive hydrogel for synergistic treatment of SCI. A conductive hydrogel combined with TMP demonstrates good electrical and mechanical properties as well as superior biocompatibility. Furthermore, it also facilitates sustained local release of TMP at the implantation site. Furthermore, the TMP-loaded electroconductive hydrogel could suppress oxidative stress responses, thereby diminishing endothelial cell apoptosis and the breakdown of tight junction proteins. This concerted action repairs BSCB integrity. Concurrently, myelin-associated axons and neurons are protected against death, which meaningfully restore neurological functions post spinal cord injury. Hence, these findings indicate that combining the electroconductive hydrogel with TMP presents a promising avenue for potentiating drug efficacy and synergistic repair following SCI.


Subject(s)
Hydrogels , Neurons , Pyrazines , Spinal Cord Injuries , Pyrazines/chemistry , Pyrazines/pharmacology , Spinal Cord Injuries/drug therapy , Hydrogels/chemistry , Hydrogels/pharmacology , Hydrogels/chemical synthesis , Animals , Neurons/drug effects , Rats, Sprague-Dawley , Rats , Spinal Cord/drug effects , Electric Conductivity , Neuroprotective Agents/chemistry , Neuroprotective Agents/pharmacology , Mice , Apoptosis/drug effects , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology
2.
Carbohydr Polym ; 334: 122068, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38553197

ABSTRACT

The fabrication of highly elastic, fatigue-resistant and conductive hydrogels with antibacterial properties is highly desirable in the field of wearable devices. However, it remains challenging to simultaneously realize the above properties within one hydrogel without compromising excellent sensing ability. Herein, we fabricated a highly elastic, fatigue-resistant, conductive, antibacterial and cellulose nanocrystal (CNC) enhanced hydrogel as a sensitive strain sensor by the synergistic effect of biosynthesized selenium nanoparticles (BioSeNPs), MXene and nanocellulose. The structure and potential mechanism to generate biologically synthesized SeNPs (BioSeNPs) were systematically investigated, and the role of protease A (PrA) in enhancing the adsorption between proteins and SeNPs was demonstrated. Additionally, owing to the incorporation of BioSeNPs, CNC and MXene, the synthesized hydrogels showed high elasticity, excellent fatigue resistance and antibacterial properties. More importantly, the sensitivity of hydrogels determined by the gauge factor was as high as 6.24 when a high strain was applied (400-700 %). This study provides a new horizon to synthesize high-performance antibacterial and conductive hydrogels for soft electronics applications.


Subject(s)
Nanoparticles , Nitrites , Selenium , Transition Elements , Anti-Bacterial Agents/pharmacology , Cellulose/pharmacology , Electric Conductivity , Hydrogels/pharmacology
3.
Mater Horiz ; 11(8): 2010-2020, 2024 04 22.
Article in English | MEDLINE | ID: mdl-38362790

ABSTRACT

Flexible and stretchable heaters are increasingly recognized for their great potential in wearable thermotherapy to treat muscle spasms, joint injuries and arthritis. However, issues like lengthy processing, high fabrication cost, and toxic chemical involvement are obstacles on the way to popularize stretchable heaters for medical use. Herein, using a single-step customizable laser fabrication method, we put forward the design of cost-effective wearable laser-induced graphene (LIG) heaters with kirigami patterns, which offer multimodal stretchability and conformal fit to the skin around the human body. First, we develop the manufacturing process of the LIG heaters with three different kirigami patterns enabling reliable stretchability by out-of-plane buckling. Then, by adjusting the laser parameters, we confirm that the LIG produced by medium laser power could maintain a balance between mechanical strength and electrical conductivity. By optimizing cutting-spacing ratios through experimental measurements of stress, resistance and temperature profiles, as well as finite element analysis (FEA), we determine that a larger cutting-spacing ratio within the machining precision will lead to better mechanical, electrical and heating performance. The optimized stretchable heater in this paper could bear significant unidirectional strain over 100% or multidirectional strain over 20% without major loss in conductivity and heating performance. On-body tests and fatigue tests also proved great robustness in practical scenarios. With the advantage of safe usage, simple and customizable fabrication, easy bonding with skin, and multidirectional stretchability, the on-skin heaters are promising to substitute the traditional heating packs/wraps for thermotherapy.


Subject(s)
Graphite , Hyperthermia, Induced , Lasers , Wearable Electronic Devices , Humans , Hyperthermia, Induced/methods , Hyperthermia, Induced/instrumentation , Equipment Design , Finite Element Analysis , Electric Conductivity
4.
Adv Healthc Mater ; 13(17): e2303219, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38198617

ABSTRACT

Irregular electrical impulses in atrium are the leading cause of atrial fibrillation (AF), resulting in fatal arrhythmia and sudden cardiac death. Traditional medication and physical therapies are widely used, but generally suffer problems in serious physical damage and high surgical risks. Flexible and soft implants have great potential to be a novel approach for heart diseases therapy. A conductive hydrogel-based mesh cardiac patch is developed for application in AF elimination. The designed mesh patch with rhombic-shaped structure exhibits excellent flexibility, surface conformability, and deformation compliance, making it fit well with heart surface and accommodate to the deformation during heart beating. Moreover, the mechanical elastic and shape-memory properties of the mesh patch enable a minimally invasive injection of the patch into living animals. The mesh patch is implanted on the atrium surface for one month, indicating good biocompatibility and stability. Furthermore, the conductive patch can effectively eliminate AF owing to the conductivity and high charge storage capability (CSC) of the hydrogel. The proposed scheme of cardiac bioelectric signal modulation using conductive hydrogel brings new possibility for the treatment of arrhythmia diseases.


Subject(s)
Atrial Fibrillation , Electric Conductivity , Hydrogels , Atrial Fibrillation/therapy , Animals , Hydrogels/chemistry , Hydrogels/pharmacology , Rats , Rats, Sprague-Dawley , Male
5.
Int J Biol Macromol ; 257(Pt 2): 128757, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38092123

ABSTRACT

Hydrogels from natural polymers are eco-friendly, biocompatible and adjustable for manufacturing wearable sensors. However, it is still challenging to prepare natural polymer hydrogel sensors with excellent properties (e.g., high conductivity). Here, we developed a physically cross-linked, highly conductive and multifunctional hydrogel (named PPTP) to address this challenge. The natural renewable pectin-based PPTP hydrogel is synthesized by introducing tannic acid (TA), calcium chloride (CaCl2), and sodium chloride (NaCl) into the pectin/polyvinyl alcohol (PVA) dual network structure. The hydrogel exhibits excellent characteristics, including unique tensile strength (2.6155 MPa), high electrical conductivity (7 S m-1), and high sensitivity (GF = 3.75). It is also recyclable, further enhancing its eco-friendly nature. The PPTP hydrogel can be used for monitoring human joint activities, as flexible electrodes for monitoring electrocardiogram (ECG) signals, and touchable screen pen for electronic skin. Moreover, when combined with Morse code and wireless Bluetooth technology, PPTP hydrogels can be used for underwater and land information encryption, and decryption. Our unique PPTP hydrogel offers promising opportunities for medical monitoring, information transfer, and human-computer interaction.


Subject(s)
Hydrogels , Pectins , Polyphenols , Humans , Polysaccharides , Electric Conductivity , Polymers , Sodium Chloride
6.
Water Sci Technol ; 88(11): 2707-2718, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38096063

ABSTRACT

The objective of the current study was to determine the applicability of a sensor-based dynamic control strategy for the treatment of real variable dairy wastewater by aerobic granular sludge (AGS) performing enhanced biological phosphorus removal (EBPR). Two parallel sequencing batch reactors (SBRs) were set up that used only an anaerobic feast/aerobic famine microbial selection strategy to successfully obtain sludge granulation. SBR-STA used a fixed cycle length, while the duration of the reaction steps in SBR-DYN was variable. The control strategy was based solely on (derived) signals from low-cost and common sensors. The profile of the electric conductivity during the anaerobic reaction step was related to the microbial release of phosphate (PO4-P) and the associated uptake of dissolved organic carbon (DOC) by polyphosphate-accumulating organisms (PAOs). Control of the aerobic reaction step was based on the oxygen uptake rate (OUR). This resulted in a dynamic reactor operation with significant efficiency gains, such as 32% shorter cycle times and 42% higher sludge loading rates without impairing the effluent quality. These results extend the existing potential of indirect control strategies to full biological nutrient removal processes, which may be of great assistance to the operators and designers of industrial installations.


Subject(s)
Sewage , Water Purification , Waste Disposal, Fluid/methods , Bioreactors , Phosphorus , Electric Conductivity , Oxygen
7.
Sci Rep ; 13(1): 17408, 2023 10 13.
Article in English | MEDLINE | ID: mdl-37833440

ABSTRACT

Electro-stimulation to alleviate spasticity, pain and to increase mobility has been used successfully for years. Usually, gelled electrodes are used for this. In a garment intended for repeated use such electrodes must be replaced. The Mollii-suit by the company Inerventions utilises dry conductive rubber electrodes. The electrodes work satisfactory, but the garment is cumbersome to fit on the body. In this paper we show that knitted dry electrodes can be used instead. The knitted electrodes present a lower friction against the skin and a garment is easily fitted to the body. The fabric is stretchable and provides a tight fit to the body ensuring electrical contact. We present three candidate textrodes and show how we choose the one with most favourable features for producing the garment. We validate the performance of the garment by measuring three electrical parameters: rise time (10-90%) of the applied voltage, net injected charge and the low frequency value of the skin-electrode impedance. It is concluded that the use of flat knitting intarsia technique can produce a garment with seamlessly integrated conductive leads and electrodes and that this garment delivers energy to the body as targeted and is beneficial from manufacturing and comfort perspectives.


Subject(s)
Electric Stimulation Therapy , Textiles , Electric Conductivity , Electrodes , Clothing
8.
Environ Monit Assess ; 195(10): 1189, 2023 Sep 12.
Article in English | MEDLINE | ID: mdl-37698726

ABSTRACT

In order to detect the effects of different stressors on the littoral diatom assemblages and biodiversity of the lentic systems in two different basins in Türkiye, 15 lentic systems in the Akarçay and Asi basins were sampled three times (spring, summer, and fall) for littoral diatoms and environmental variables. The biological assessment of these sites was also evaluated using 9 different river and lake diatom indices. Based on the total phosphorus (TP), total nitrogen (TN), electrical conductivity (EC), salinity (SAL) values, and dominant diatom species, three lentic systems in Akarçay Basin (Lake Eber, 26 Agustos Pond, and Lake Karamik) were more eutrophic and under the pressure of anthropogenic and climatic (precipitation) stressors. Trophic diatom index for lakes (TDIL) showed a higher correlation with TN and TP and was the most effective index in explaining ecological quality in 15 lentic systems. The species richness of diatoms was also negatively affected by EC and SAL values. The lentic systems of the two basins were separated from each other based on the species composition and the distribution of the dominant species with the effect of altitude (ALT). Considering the distribution of diatom assemblage of the lentic systems in these two basins, anthropogenic, climatic, and geographical factors have become prominent to shape the diatom community structure.


Subject(s)
Diatoms , Environmental Monitoring , Altitude , Biodiversity , Electric Conductivity , Nitrogen , Phosphorus
9.
Phys Med Biol ; 68(20)2023 10 06.
Article in English | MEDLINE | ID: mdl-37703902

ABSTRACT

Objective.Application of alternating electrical fields (AEFs) in the kHz range is an established treatment modality for primary and recurrent glioblastoma. Preclinical studies would enable innovations in treatment monitoring and efficacy, which could then be translated to benefit patients. We present a practical translational process converting image-based data into 3D rat head models for AEF simulations and study its sensitivity to parameter choices.Approach.Five rat head models composed of up to 7 different tissue types were created, and relative permittivity and conductivity of individual tissues obtained from the literature were assigned. Finite element analysis was used to model the AEF strength and distribution in the models with different combinations of head tissues, a virtual tumor, and an electrode pair.Main results.The simulations allowed for a sensitivity analysis of the AEF distribution with respect to different tissue combinations and tissue parameter values.Significance.For a single pair of 5 mm diameter electrodes, an average AEF strength inside the tumor exceeded 1.5 V cm-1, expected to be sufficient for a relevant therapeutic outcome. This study illustrates a robust and flexible approach for simulating AEF in different tissue types, suitable for preclinical studies in rodents and translatable to clinical use.


Subject(s)
Electric Stimulation Therapy , Glioblastoma , Humans , Rats , Animals , Glioblastoma/pathology , Electricity , Electric Conductivity , Electric Stimulation Therapy/methods
10.
Biosensors (Basel) ; 13(9)2023 Sep 08.
Article in English | MEDLINE | ID: mdl-37754112

ABSTRACT

Liposomes are prominent nanosystems for drug delivery, with potential extending beyond isolated drugs. Ethanol-aqueous plant extracts can be encapsulated within liposomes to protect bioactive compounds (secondary metabolites) from rapid oxidation and enable sustained release. Determining which compound classes are present in each extract and the encapsulation efficiency (EE) of these extracts in liposomes is crucial for nanocarrier functionality. This involves assessing the ratio of bioactive substances within liposomes to the total content. However, quantifying EE for non-isolated compounds poses challenges due to the need for advanced analytical equipment and biosensing approaches. This study introduces an innovative method for EE quantification, using a conductivity electrode (k = 0.842/cm) to establish an EE biosensing technology. By correlating dynamic light scattering (DLS), zeta potential (ZP), and electrical conductivity (Cnd) data with the conductivity meter's calibration curve, a robust relationship between the free extract concentration and Cnd (r2 ≥ 0.950) was established. Lavender-loaded liposomes demonstrated an EE of 56.33%, while wormwood and oregano formulations exhibited high EEs of 94.33% and 91.70%, respectively. In contrast, sage-loaded liposomes exhibited an inadequate EE, encapsulating only approximately 0.57% of the extract. The straightforward quantification of the free extract within liposome formulations, compared to more complex approaches, could facilitate EE determination and support future characterizations.


Subject(s)
Drug Delivery Systems , Liposomes , Calibration , Color , Electric Conductivity
11.
Int J Mol Sci ; 24(15)2023 Jul 31.
Article in English | MEDLINE | ID: mdl-37569645

ABSTRACT

Graphene is the first two-dimensional material that becomes the center material in various research areas of material science, chemistry, condensed matter, and engineering due to its advantageous properties, including larger specific area, lower density, outstanding electrical conductivity, and ease of processability. These properties attracted the attention of material researchers that resulted in a large number of publications on EMI shielding in a short time and play a central role in addressing the problems and challenges faced in this modern era of electronics by electromagnetic interference. After the popularity of graphene, the community of material researchers investigated other two-dimensional materials like MXenes, hexagonal boron nitride, black phosphorous, transition metal dichalcogenides, and layered double hydroxides, to additionally enhance the EMI shielding response of materials. The present article conscientiously reviews the current progress in EMI shielding materials in reference to two-dimensional materials and addresses the future challenges and research directions to achieve the goals.


Subject(s)
Graphite , Electric Conductivity , Electronics , Phosphorus
12.
Sensors (Basel) ; 23(14)2023 Jul 19.
Article in English | MEDLINE | ID: mdl-37514821

ABSTRACT

The increasing interest in karate has also attracted the attention of researchers, especially in combining the equipment used by practitioners with technology to prevent injuries, improve technical skills and provide appropriate scoring. Contrary to the sport of taekwondo, the development of a smart body protector in the sport of karate is still a niche field to be researched. This study focused on developing piezoresistive, textile-based pressure sensors using piezoresistive film, conductive fabric as well as different bonding materials and methods. Primarily, small-scale sensors were produced using ultrasonic welding, hot press welding and oven curing. These were characterized using a universal testing machine and specific conditioning and data-acquisition hardware combined with custom processing software. Large-scale sensors were then manufactured to be placed inside the karate body protector and characterized using cyclic testing. The conditioning circuit allows flexible gain adjustment, and it was possible to obtain a stable signal with an output of up to 0.03 V/N, an adequate signal for the tested force range. The transfer function shows some drift over the cycles, in addition to the expected hysteresis and slight nonlinearity, which can be compensated for. Finally, the configuration with the best results was tested in real practice tests; during these tests the body protector was placed on a dummy as well as on a person. The results showed that the piezoresistive textile-based pressure sensor produced is able to detect and quantify the impact of even light punches, providing an unobtrusive means for performance monitoring and score calculation for competitive practice of this sport.


Subject(s)
Martial Arts , Wearable Electronic Devices , Humans , Textiles , Electric Conductivity , Software
13.
IEEE Trans Biomed Eng ; 70(12): 3461-3468, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37352086

ABSTRACT

OBJECTIVE: The study describes the development and testing of a dry surface stimulation flexible electrode (herein referred to as Flexatrode), a low-cost, flexible, and scalable elastomeric nanocomposite using carbon black (CB) and polydimethylsiloxane (PDMS). METHODS: Flexatrodes composed of CB and PDMS were developed and tested for mechanical and functional stability up to 7 days. Uniform CB distribution was achieved by optimizing the dispersion process using toluene and methyl-terminated PDMS. Electromechanical testing in the through thickness directions over a long-term duration demonstrated stability of Flexatrode. Thermal stability of Flexatrode for up to a week was tested and validated, thus mitigating concerns of heat generation and deleterious skin reactions such as vasodilation or erythema. RESULTS: 25 wt.% CB was determined to be the optimal concentration. Electrical and thermal stability were demonstrated in the through thickness direction. CONCLUSION: Flexatrode provides stable electrical properties combined with high flexibility and elasticity. Electrotherapy treated chronic wounds were 81.9% smaller than baseline at day 10. Wounds that received an inactive device (device without any electrical stimulation) were 58.1% smaller than baseline and wounds that received standard of care treatment were 62.2% smaller than baseline. SIGNIFICANCE: The increasing need for wearable bioelectronics requiring long-term monitoring/treatment has highlighted the limitations of sustained use of gel-based electrodes. These can include skin irritation, bacterial overgrowth at the electrode site, gel dehydration over time, and signal degradation due to eccrine sweat formation. Flexatrode provides stable performance in a nanocomposite with scalable fabrication, thus providing a promising platform technology for wearable bioelectronics.


Subject(s)
Nanocomposites , Electric Conductivity , Elasticity , Electrodes
14.
Molecules ; 28(11)2023 Jun 02.
Article in English | MEDLINE | ID: mdl-37298996

ABSTRACT

ZnIn2S4 (ZIS) is widely used in the field of photocatalytic hydrogen production due to its unique photoelectric properties. Nonetheless, the photocatalytic performance of ZIS usually faces problems of poor conductivity and rapid recombination of charge carriers. Heteroatom doping is often regarded as one of the effective strategies for improving the catalytic activity of photocatalysts. Herein, phosphorus (P)-doped ZIS was prepared by hydrothermal method, whose photocatalytic hydrogen production performance and energy band structure were fully studied. The band gap of P-doped ZIS is about 2.51 eV, which is slightly smaller than that of pure ZIS. Moreover, due to the upward shift of its energy band, the reduction ability of P-doped ZIS is enhanced, and P-doped ZIS also exhibits stronger catalytic activity than pure ZIS. The optimized P-doped ZIS exhibits a hydrogen production rate of 1566.6 µmol g-1 h-1, which is 3.8 times that of the pristine ZIS (411.1 µmol g-1 h-1). This work provides a broad platform for the design and synthesis of phosphorus-doped sulfide-based photocatalysts for hydrogen evolution.


Subject(s)
Hydrogen , Light , Electric Conductivity , Phosphorus
15.
Adv Sci (Weinh) ; 10(24): e2302632, 2023 08.
Article in English | MEDLINE | ID: mdl-37340589

ABSTRACT

Regeneration of over 10 mm long peripheral nerve defects remains a challenge due to the failure of regeneration by prolonged axotomy and denervation occurring in long-term recovery. Recent studies reveal that conductive conduits and electrical stimulation accelerate the regeneration of long nerve defects. In this study, an electroceutical platform combining a fully biodegradable conductive nerve conduit and a wireless electrical stimulator is proposed to maximize the therapeutic effect on nerve regeneration. Fully biodegradable nerve conduit fabricated using molybdenum (Mo) microparticles and polycaprolactone (PCL) can eliminate the unwanted effects of non-degradable implants, which occupy nerve paths and need to be removed through surgery increasing the risk of complications. The electrical and mechanical properties of Mo/PCL conduits are optimized by controlling the amounts of Mo and tetraglycol lubricant. The dissolution behavior and electrical conductivity of biodegradable nerve conduits in the biomimetic solutions are also evaluated. In in vivo experiments, the integrated strategy of a conductive Mo/PCL conduit with controlled therapeutic electrical stimulation shows accelerated axon regeneration for long sciatic nerve defects in rats compared to the use of the Mo/PCL conduit without stimulation and has a significant therapeutic effect based on the results obtained from the functional recovery test.


Subject(s)
Axons , Nerve Regeneration , Rats , Animals , Nerve Regeneration/physiology , Prostheses and Implants , Sciatic Nerve/physiology , Electric Conductivity
16.
Angew Chem Int Ed Engl ; 62(26): e202301489, 2023 Jun 26.
Article in English | MEDLINE | ID: mdl-37129146

ABSTRACT

Eutectogels are an emerging family of soft ionic materials alternative to ionic liquid gels and organogels, offering fresh perspectives for designing functional dynamic platforms in water-free environments. Herein, the first example of mixed ionic and electronic conducting supramolecular eutectogel composites is reported. A fluorescent glutamic acid-derived low-molecular-weight gelator (LMWG) was found to self-assemble into nanofibrillar networks in deep eutectic solvents (DES)/poly(3,4-ethylenedioxythiophene) (PEDOT): chondroitin sulfate dispersions. These dynamic materials displayed excellent injectability and self-healing properties, high ionic conductivity (up to 10-2  S cm-1 ), good biocompatibility, and fluorescence imaging ability. This set of features turns the mixed conducting supramolecular eutectogels into promising adaptive materials for bioimaging and electrostimulation applications.


Subject(s)
Chondroitin Sulfates , Coloring Agents , Electric Conductivity , Electronics , Glutamic Acid
17.
Phys Med Biol ; 68(8)2023 04 05.
Article in English | MEDLINE | ID: mdl-36893468

ABSTRACT

Objective. The treatment of glioblastoma (GBM) using low intensity electric fields (∼1 V cm-1) is being investigated using multiple implanted bioelectrodes, which was termed intratumoral modulation therapy (IMT). Previous IMT studies theoretically optimized treatment parameters to maximize coverage with rotating fields, which required experimental investigation. In this study, we employed computer simulations to generate spatiotemporally dynamic electric fields, designed and purpose-built an IMT device forin vitroexperiments, and evaluated the human GBM cellular responses to these fields.Approach. After measuring the electrical conductivity of thein vitroculturing medium, we designed experiments to evaluate the efficacy of various spatiotemporally dynamic fields: (a) different rotating field magnitudes, (b) rotating versus non-rotating fields, (c) 200 kHz versus 10 kHz stimulation, and (d) constructive versus destructive interference. A custom printed circuit board (PCB) was fabricated to enable four-electrode IMT in a 24-well plate. Patient derived GBM cells were treated and analyzed for viability using bioluminescence imaging.Main results. The optimal PCB design had electrodes placed 6.3 mm from the center. Spatiotemporally dynamic IMT fields at magnitudes of 1, 1.5, and 2 V cm-1reduced GBM cell viability to 58%, 37% and 2% of sham controls respectively. Rotating versus non-rotating, and 200 kHz versus 10 kHz fields showed no statistical difference. The rotating configuration yielded a significant reduction (p< 0.01) in cell viability (47 ± 4%) compared to the voltage matched (99 ± 2%) and power matched (66 ± 3%) destructive interference cases.Significance. We found the most important factors in GBM cell susceptibility to IMT are electric field strength and homogeneity. Spatiotemporally dynamic electric fields have been evaluated in this study, where improvements to electric field coverage with lower power consumption and minimal field cancellations has been demonstrated. The impact of this optimized paradigm on cell susceptibility justifies its future use in preclinical and clinical trial investigations.


Subject(s)
Brain Neoplasms , Electric Stimulation Therapy , Glioblastoma , Humans , Electric Stimulation Therapy/methods , Brain Neoplasms/therapy , Glioblastoma/radiotherapy , Electric Conductivity
18.
Adv Colloid Interface Sci ; 314: 102860, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36931199

ABSTRACT

Polypyrrole (PPy) is one of the most studied conductive polymers due to its electrical conductivity and biological properties, which drive the possibility of numerous applications in the biomedical area. The physical-chemical features of PPy allow the manufacture of biocompatible devices, enhancing cell adhesion and proliferation. Furthermore, owing to the electrostatic interactions between the negatively charged bacterial cell wall and the positive charges in the polymer structure, PPy films can perform an effective antimicrobial activity. PPy is also frequently associated with biocompatible agents and antimicrobial compounds to improve the biological response. Thus, this comprehensive review appraised the available evidence regarding the PPy-based films deposited on metallic implanted devices for biomedical applications. We focus on understanding key concepts that could influence PPy attributes regarding antimicrobial effect and cell behavior under in vitro and in vivo settings. Furthermore, we unravel the several agents incorporated into the PPy film and strategies to improve its functionality. Our findings suggest that incorporating other elements into the PPy films, such as antimicrobial agents, biomolecules, and other biocompatible polymers, may improve the biological responses. Overall, the basic properties of PPy, when combined with other composites, electrostimulation techniques, or surface treatment methods, offer great potential in biocompatibility and/or antimicrobial activities. However, challenges in synthesis standardization and potential limitations such as low adhesion and mechanical strength of the film must be overcome to improve and broaden the application of PPy film in biomedical devices.


Subject(s)
Polymers , Pyrroles , Polymers/pharmacology , Polymers/chemistry , Pyrroles/pharmacology , Pyrroles/chemistry , Cell Adhesion , Electric Conductivity
19.
Bioelectromagnetics ; 44(1-2): 26-46, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36794844

ABSTRACT

Numerical investigation of the interaction of electromagnetic fields with eukaryotic cells requires specifically adapted computer models. Virtual microdosimetry, used to investigate exposure, requires volumetric cell models, which are numerically challenging. For this reason, a method is presented here to determine the current and volumetric loss densities occurring in single cells and their distinct compartments in a spatially accurate manner as a first step toward multicellular models within the microstructure of tissue layers. To achieve this, 3D models of the electromagnetic exposure of generic eukaryotic cells of different shape (i.e. spherical and ellipsoidal) and internal complexity (i.e. different organelles) are performed in a virtual, finite element method-based capacitor experiment in the frequency range from 10 Hz to 100 GHz. In this context, the spectral response of the current and loss distribution within the cell compartments is investigated and any effects that occur are attributed either to the dispersive material properties of these compartments or to the geometric characteristics of the cell model investigated in each case. In these investigations, the cell is represented as an anisotropic body with an internal distributed membrane system of low conductivity that mimics the endoplasmic reticulum in a simplified manner. This will be used to determine which details of the cell interior need to be modeled, how the electric field and the current density will be distributed in this region, and where the electromagnetic energy is absorbed in the microstructure regarding electromagnetic microdosimetry. Results show that for 5 G frequencies, membranes make a significant contribution to the absorption losses. © 2023 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society.


Subject(s)
Electromagnetic Fields , Electromagnetic Radiation , Computer Simulation , Electricity , Electric Conductivity , Models, Biological
20.
Sci Rep ; 13(1): 1159, 2023 Jan 20.
Article in English | MEDLINE | ID: mdl-36670164

ABSTRACT

We have studied the optical conductivity of a quasi two-dimensional [Formula: see text] in the presence of external magnetic field and spin-orbit coupling. Specially, we address the frequency dependence of optical conductivity due to spin-orbit interaction. Using linear response theory the behavior of optical conductivity has been obtained within Green's function method. We have also considered the effects of uniaxial and biaxial in-plane strain on the optical absorption of [Formula: see text] layer. In the absence of external magnetic field with negative uniaxial strain parameter, optical conductivity includes Drude weight at zero frequency limit while Drude weight vanishes for [Formula: see text] layer under positive uniaxial strain. Our results show that the increase of uniaxial positive strain parameter causes to move the position peak to the higher frequencies. In contrast to uniaxial strain case, the Drude weight in optical conductivity appears at positive biaxial strain value 0.15. Also we have studied the effects of magnetic field, electron doping, hole doping in the presence of spin-orbit coupling on frequency dependence of optical conductivity of [Formula: see text] in details. The magnetic field dependence of optical absorption shows a monotonic decreasing behavior for each value of temperature in the absence of strain parameter.


Subject(s)
Electrons , Manipulation, Osteopathic , Electric Conductivity , Magnetic Fields , Manipulation, Orthopedic
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