Electrode Surface Temperature Research Articles

Electrode Surface Heating with Organic Films Improves CO2 Reduction Kinetics on Copper.

Management of the electrode surface temperature is an understudied aspect of (photo)electrode reactor design for complex reactions, such as CO2 reduction. In this work, we study the impact of local electrode heating on electrochemical reduction of CO2 reduction. Using the ferri/ferrocyanide open circuit voltage as a reporter of the effective reaction temperature, we reveal how the interplay of surface heating and convective cooling presents an opportunity for cooptimizing mass transport and thermal assistance of electrochemical reactions, where we focus on reduction of CO2 to carbon-coupled (C2+) products. The introduction of an organic coating on the electrode surface facilitates well-behaved electrode kinetics with near-ambient bulk electrolyte temperature. This approach helps to probe the fundamentals of thermal effects in electrochemical reactions, as demonstrated through Bayesian inference of Tafel kinetic parameters from a suite of high throughput experiments, which reveal a decrease in overpotential for C2+ products by 0.1 V on polycrystalline copper via 60 °C surface heating.

Measurement of Electrode Surface Temperature and Post-Arc Current in Vacuum Interrupter

Measurement of Electrode Surface Temperature and Post-Arc Current in Vacuum Interrupter

Investigating Charge Transfer Mechanisms at Graphene-Electrolyte Interfaces for Enabling Rechargeable Li-CFx Batteries Via Electrochemical Fluorination

Li-CFx batteries are a promising high energy density option for wider electrification of the transportation sector, but limited rechargeability remains a major challenge. In this study, we explore electrochemical fluorination of graphene as a potential solution and build a mechanistic understanding of this process. Specifically, we investigate the charge transfer mechanisms at the graphene-electrolyte interfaces during fluorination, which is a key component for enabling rechargeability. We employ density functional theory and molecular dynamics simulations to examine the effect of electrode surface morphology, electrolyte composition, and temperature on the thermodynamics and charge transfer kinetics. We explore the role of electron and ion hopping mechanisms in charge transfer and evaluate the influence of surface defects and adsorbates on the charge transfer rate. Our findings provide important insights into the fundamental mechanisms governing charge transfer at graphene-electrolyte interfaces and can guide the design of the electrochemical fluorination process of graphene for enabling rechargeable Li-CFx batteries. This work represents a critical step towards achieving the next milestone in the wider electrification of the transportation sector.

Modeling and Analysis of the Drying Process of Lithium-Ion Battery Electrodes Based on Non-Steady-State Drying Kinetics

The drying process of lithium-ion battery electrodes is one of the key processes for manufacturing electrodes with high surface homogeneity and is one of the most energy-consuming stages. The choice of the drying parameters has a significant impact on the electrode properties and the production efficiency. In response to these issues, this study establishes the non-steady-state drying kinetic equation for the electrodes, revealing the comprehensive effects of various dominant factors on the drying process. The drying rate is closely related to the electrode surface temperature, thickness, and other factors. Furthermore, this study proposes a coupled model of hot air drying field and capillary porous electrode solvent evaporation. The results showed that approximately 90% of the solvent was removed in less than half of the drying time. Then, the mechanism and control factors of electrode solvent evaporation are analyzed. During the preheating phase, the drying rate is controlled by electrode heating and temperature rise. In the constant velocity phase, it is regulated by the heat transfer from the surface airflow, while in the deceleration phase, it is affected by the mass transfer from the electrodes. Additionally, the effects of different thicknesses, temperatures, and airflow speeds on the drying process were investigated. Finally, experimental verification demonstrated the optimal parameters within the scope of the study: a temperature of 363.15 K and airflow speeds of 2.3 m/s result in a higher drying rate, as well as favorable mechanical performance.

Temperature dependent electrochemical reduction of CO2 at temperature controllable-rotating disk electrode modified with bismuth film

Temperature is an important parameter regulating the selectivity and reaction activity of electrochemical CO2 reduction reaction (CO2RR). However, it is challenging to evaluate the effect of temperature on electrochemical CO2RR without changing the CO2 solubility in water. Herein, a glassy carbon temperature controllable-rotating disk electrode (TCRDE-GC) was fabricated and the heat transfer was studied using temperature transfer coefficient (αT). As the only parameter required to calibrate the electrode surface temperature (Ts), αT was found to be correlated with the square root of the angular velocity of rotation. A bismuth film modified TCRDE was used to investigate Ts function on electrochemical CO2RR in the CO2-saturated K2SO4 solution where the CO2 solubility did not change. The apparent activation energy of electrochemical CO2RR was firstly reported as 46 kJ⋅mol−1. Electrochemical and ion chromatography results suggested that increasing Ts could accelerate the reaction rate of electrochemical CO2RR (increased by 170% with Ts increasing from 25 to 65 °C) and enhance product yield (increased by 40% with Ts increasing from 25 to 45 °C), whereas, could not change the type of main products. There was no regular effect of Ts on Faradic efficiency of HCOO− production. This work provides a new method to study the effect of electrode surface temperature on the CO2RR at the electrode / solution interface and it may be extended to other similar systems for further in-depth investigation.

Electrode plasma formation and melt in Z -pinch accelerators

Recent studies of power flow and particle transport in multi-MA pulsed-power accelerators demonstrate that electrode plasmas may reduce accelerator efficiency by shunting current upstream from the load [Bennett et al., Phys. Rev. Accel. Beams 24, 060401 (2021)]. The detailed generation and evolution of these electrode plasmas are examined here using fully relativistic, Monte Carlo particle-in-cell (PIC) and magnetohydrodynamic (MHD) simulations over a range of peak currents (8--48 MA). The PIC calculations, informed by vacuum science, describe the electrode surface breakdown and particle transport prior to electrode melt. The MHD calculations show the bulk electrode evolution during melt. The physical description provided by this combined study begins with the rising local magnetic field that increases the local electrode surface temperature. This initiates the thermal desorption of contaminants from the electrode surface, with contributions from atoms outgassing from the bulk metal. The contaminants rapidly ionize forming a ${10}^{15}--{10}^{18}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ plasma that is effectively resistive while weakly collisional because it is created within, and rapidly penetrated by, a strong magnetic field ($>30\text{ }\text{ }\mathrm{T}$). Prior to melting, the density of this surface plasma is limited by the concentration of absorbed contaminants in the bulk ($\ensuremath{\sim}{10}^{19}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ for hydrogen), its diffusion, and ionization. Eventually, the melting electrodes form a conducting plasma (${10}^{21}--{10}^{23}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$) that experiences $\mathbf{j}\ifmmode\times\else\texttimes\fi{}\mathbf{B}$ compression and a typical decaying magnetic diffusion profile. This physical sequence ignores the transport of collisional plasmas of ${10}^{19}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ which may arise from electrode defects and associated instabilities. Nonetheless, this picture of plasma formation and melt may be extrapolated to higher-energy pulsed-power systems.

Identification of the Dominant Factor for Droplet Ejection from a Tungsten Electrode during AC Tungsten Inert Gas Welding by Visualisation of Electrode Phenomena

Droplet ejections from a molten tungsten electrode during alternating current tungsten inert gas (AC TIG) welding were observed successfully by a high-speed video captured at 75,000 fps. The welding conditions and timings that were likely to occur were investigated. The electrode surface temperature was also measured. A crater was formed on the surface of the electrode, and a droplet ejection occurred following the separation of the tip of the ridge growing from the centre of the crater. A series of droplet ejections occurred on a time scale of approximately 0.4 ms. Our results showed that the high temperature of the electrode surface was the common factor for droplet ejections. The dominant force for droplet ejection was discussed by estimating the balance of forces acting on the molten electrode surface. The pressure due to surface tension was the largest pressure at any time during the AC cycle, which decreased in the second half of the EP period. Our findings suggest that the surface tension was the dominant force for changing the electrode shape and that droplet ejections occurred when the surface tension decreased due to the increase in the electrode surface temperature.

Numerical Analysis of Airfoil Flow Control Using a Nanosecond Pulsed Plasma Actuator

The control mechanism of a nanosecond dielectric barrier discharge (NS-DBD) actuator for suppressing laminar separation on airfoils was investigated using two-dimensional scale-adaptive simulations. To model the control effect of the NS-DBD actuator, a surface heating approach based on the analytical solution for transient one-dimensional heat conduction has been used. The focus of the investigation lies in the study of vortex formation and evolution induced by the actuator. A NACA 0015 profile was simulated at 14° with 250,000 chord-based Reynolds number. Regarding energy deposition, a low-energy case and a high-energy case were simulated. Several actuation parameters were varied, including the electrode position and surface temperature. In addition, the influence of constant and temperature-dependent modeling of the kinematic viscosity was investigated. The results for the time-averaged pressure coefficients show excellent agreement with measurement results. High grid resolution in the boundary layer allowed a detailed investigation of the vortex formation process. The main finding is that vortices are generated by baroclinic torque and vortex dilatation and not by a Kelvin–Helmholtz instability. Initially, tiny vortices form at the beginning of the separation region. Subsequently, these vortices are carried downstream and grow in size, thus preventing full separation due to momentum transfer from the external flow.

Highly Selective Reduction of CO2 to Methane Induced by Subzero Depression of the Electrode Surface Temperature

In the CO2 reduction reaction, achieving single product selectivity with comprehensive understanding of the corresponding reaction mechanism is considered a holy grail. Among numerous reactor and electrode surface parameters, temperature has surprisingly seldom been considered as a variable for selectivity regulation due to the limited range of control in aqueous electrolytes. Here we employed a reactor design for electrode surface cooling to subzero temperatures with minimal impact on the bulk electrolyte temperature. Distinct reactivity patterns were observed when the electrode was surface-cooled, compared to those of experiments when the entire reactor was chilled. Much improved methane single product selectivity was achieved (80%, comparable to the best efficiencies reported thus far) at subzero-cooled electrodes. Moreover, significantly lower overpotentials (ca. 300 mV at identical current density) were maintained with surface cooling because the temperature of the electrolyte bath was not affected. In situ IR spectroscopy revealed that the electrode surface-adsorbed CO species was the chemical intermediate in the methane-producing pathway.

Study on Pseudospark Switch Triggered by 532-nm Focused Laser

The influence of laser energy, irradiation position, photoelectric material, and anode voltage on the trigger characteristics of a pseudospark switch triggered by a 532-nm nanosecond focused laser is studied. The parameters of the seed electrons induced by the interaction between the focused laser and metal are measured. It is found that the increase of laser energy and anode voltage can increase the current density of seed electrons, reduce the time of electrons diffusion to the cathode hole, and thus reduce the trigger delay. When the irradiation position is close to the cathode hole, the surface electric field is larger, which is conducive to achieving a smaller trigger delay and jitter under low laser energy. The seed electron current induced by the focused laser has two peaks. The first peak mainly corresponds to the thermal emission, with a short time delay and narrow pulsewidth, contributing to the trigger. The second peak mainly corresponds to the electrode surface ablation, with a long time delay and large pulsewidth, contributing little to the trigger. In this case, the electrode surface temperature is more important than the work function, so Cu has better electron emission characteristics than Mg. With the increase of laser energy, the number of electrons in high-energy components increases.

Comparison of Temperature and Light Distributions Around Nano-Resistors in SSI-LEDs

A recent optoelectronic device termed the Solid-State Incandescent LED (SSI-LED) was discovered by Kuo’s group in 2013 [1]. The device is made by subjecting a MOS Capacitor of transparent gate material and appropriate high-k properties to dielectric breakdown, which results in the formation of numerous nano-scale conduction paths called nano-resistors (NRs). Due to its extremely small cross-sectional area, NRs display high current densities for relatively small voltages applied across the device. Consequently, the high current densities yield high local temperatures that approach black body radiation and allow NRs to undergo incandescence, where white light is emitted from the top surface through the transparent gate electrode by thermal excitation of electrons. Since the heat generated from Joule heating is contained within the NRs, a large temperature drop occurs over the surrounding volume as the heat flux transitions from nanoscale to microscale, keeping the whole device at a much lower temperature. The light emission from the SSI-LED is similar to that of an incandescent lamp where a spectrum of a wide range of wavelengths is produced in contrast to the narrow band light emitted from the conventional pn junction-structured LED. Therefore, SSI-LEDs are suitable for natural light or white light applications [2].It is desirable to have a direct comparison of emitted light intensity, temperature, and current density profiles of not just single NRs, but of NRs with various layouts to quantify the interaction of these variables. Earlier simulations using COMSOL Multiphysics have produced temperature and current density distributions without any accompanying light intensity study [3]. Using the python simulation framework developed earlier, these variables were studied in COMSOL Multiphysics for 3 NRs arranged as a right-angled triangle, 4 NRs as a square, and 5 NRs in the shape of a '+' sign. The effect of mesh quality on the temperature and current density distributions was also quantified. Since the current density profile is highly dependent on the relative positions of the NRs, the mesh quality has a noticeable effect on the temperature surrounding the NRs. In accordance with theoretical calculations, there is a direct relationship between the current density as well as the temperature and light intensity. The resultant light intensity profiles qualitatively match experimental observations and offers a degree of validation at near screen distances. Near the circumference at the surfaces of the NRs, the current density is high [4].Figure 1(a) shows the arrangement of NRs which are all of 10 nm radius with NR centers separated from adjacent NR centers by 40 nm. Fig. 1(b) shows the light intensity (in log10 scale) of the same patterns at a distance of 1 nm above the gate electrode surface, where the light is emitted from the blackbody radiation with corresponding the CCT to the NR at the top surface. Fig. 1(c) is the temperature of the gate electrode surface for the same set of NR patterns. Blue regions have higher temperature and white regions are close to room temperature. The temperature on the gate electrode surface blends to form a distribution that resembles individual NRs, when in fact, the observed temperature is for the pattern as a whole. The possible reason for this is that temperature is distributed in terms of sinusoidal waves according to the solution of the heat equation and is largely diffused when measured at the gate electrode surface, while the light intensity distribution obtained from the Stefan-Boltzmann law and inverse square law, varies with the 4th power of temperature close to the gate and shows a significantly steeper curve with individual NRs still distinct.More detailed comparisons of the temperature and light distributions will be shown in the presentation.1. Y. Kuo and C.-C. Lin, Appl. Phys. Lett., 102, 031117 (2013).2. Y. Kuo, 2014 IEEE International Electron Devices Meeting, 4.7.1-4.7.4 (2014).3. A. Shukla and Y. Kuo, ECS J. Solid State Sci. Technol., 9, 065017 (2020).4. K. Natarajan and Y. Kuo (To be published). Figure 1

Dual-readout immunosensor based on multifunctional MXene probe triggers thesignal amplification for detection of autoimmune hepatitis marker.

A dual-readout immunosensor coupled with electrochemical impedance and temperature signal was successfully proposed to detect autoimmune hepatitis markers (ASGPR). Nb2C MXene with excellent conductivity, abundant surface functional groups, and extraordinary photothermal conversion efficiency, was designed to be a multifunctional biological probe, whose specific binding with antigen enhanced steric hindrance to generate electrochemical impedance signal, and at the same time, it had a strong optical response in the near-infrared band to achieve temperature output. In addition, poly(N-isopropyl acrylamide) (PNIPAM) was a temperature-sensitive polymer, which was adopted as the sensing matrix. When the multifunctional probe was specifically bound to the antigen, under 808-nm laser irradiation, the captured Nb2C MXene achieved photothermal conversion to increase the electrode surface temperature, and the conformation of PNIPAM changed from a free spiral to a spherical shape, further realizing double amplification of theEIS signal. Under the optimized experimental conditions, the impedance values and the temperature changes increased proportionally with the increase of the ASGPR concentration from 10-5 to 1ng/mL, and the detection limit of the immunosensor was 3.3 × 10-6ng/mL. The established dual-readout immunosensor exhibited good selectivity and acceptable stability and provided an effective detection method for autoimmune hepatitis marker detection.

Real-Time Tunable Dynamic Range for Calibration-Free Biomolecular Measurements with a Temperature-Modulated Electrochemical Aptamer-Based Sensor in an Unprocessed Actual Sample.

The sensing technologies for monitoring molecular analytes in biological fluids with high frequency and in real time could enable a broad range of applications in personalized healthcare and clinical diagnosis. However, due to the limited dynamic range (less than 81-fold), real-time analysis of biomolecular concentration varying over multiple orders of magnitude is a severe challenge faced by this class of analytical platforms. For the first time, we describe here that temperature-modulated electrochemical aptamer-based sensors with a dynamically adjustable calibration-free detection window could enable continuous, real-time, and accurate response for the several-hundredfold target concentration changes in unprocessed actual samples. Specifically, we could regulate the electrode surface temperature of sensors to obtain the corresponding dynamic range because of the temperature-dependent affinity variations. This temperature modulation method relies on an alternate hot and cold electrode reported by our group, whose surface could actively be heated and cooled without the need for altering ambient temperature, thus likewise applying for the flowing system. We then performed dual-frequency calibration-free measurements at different interface temperatures, thus achieving an extended detection window from 25 to 2500 μM for procaine in undiluted urine, 1-500 μM for adenosine triphosphate, and 5-2000 μM for adenosine in undiluted serum. The resulting sensor architecture could drastically expand the real-time response range accessible to these continuous, reagent-less biosensors.

Optimization of Resistance Spot Welding with Inserted Strips via FEM and Response Surface Methodology.

Resistance spot welding (RSW) with inserted strips, a recent variant of traditional RSW, was usually adopted in joining thin gage steels to lower the temperature developed at the electrode surface and to extend electrode life. In order to understand the influencing mechanism how the inserted strips affect the heat transfer behavior and to optimize the selection of suitable strips, an approach integrated with FEM and response surface methodology (RSM) was employed. FEM results showed that the inserted strips would not only lead to earlier initiation of weld and bigger weld size in both diameter and thickness but also lower the electrode surface temperature. Based on FEM, uniform design and RSM were further employed to build a regression model between the strip properties (i.e., electrical/thermal conductivity, thickness) and the responses (i.e., electrode tip temperature, weld diameter, and temperature at strip/sheet interface). A graphical optimization was conducted to identify a preferable strip, and a Cu55Ni45 strip with a thickness of 0.12 mm was recommended for a 0.4 mm steel sheet.

In-Situ Lithium-Ion Batteries Thermal Runaway Detection and Overcharge Performance Analysis with Internal Resistance Temperature Detector

Thermal safety is the main roadblock for applications of high energy density lithium-ion batteries (LIBs) and catastrophic LIB failure has long been a public concern. There have been numerous LIB safety testing standards and many LIB safety management devices, including isolating shutdown separators, protective electrode coatings, safety valve, etc., that are proposed for LIB service safety and reliability improvement. Despite the application of LIB tests and safety devices, thermal runaway is still reported as a major threat to equipment and personal safety. In order to improve the in-service safety, the battery management system (BMS) and safety devices need to examine and analyze the LIB performance in a real-time manner so the rapid thermal runaway progress can be detected and prevented at an early stage. Due to the complex nature and rapid reaction rate of thermal runaway, BMS and safety device with capability of comprehensive in-situ analysis of LIB thermal runaway progress have seldomly been reported. A simple BMS capable of examining the LIB thermal safety and detecting thermal runaway related reactions needs to be developed.Existing LIB thermal safety management systems typically rely on temperature sensors including thermocouples, thermistors, fiber bragg-grating sensors, etc. Despite their success in LIB surface temperature measurement, they cannot be applied for direct electrode temperature measurement, which is crucial for thermal runaway detection and prevention. Existence of thermal resistance between the battery surface and electrodes also impedes the development of quick responding LIB temperature monitoring systems based on surface temperature measurements. To address this issue, we propose the application of resistance temperature detectors (RTDs) in LIBs with the help of additive manufacturing. By embedding RTDs into operating LIBs, reliable in-situ monitoring of the electrode temperature can be achieved, which is beneficial for early detection and prevention of thermal runaway. In this work, thermal runaway in LIBs was triggered by overcharge and external short circuit (ESC). Battery temperature was recorded by the internal RTD embedded on the electrodes and external RTD mounted on the battery surface. Significant temperature difference of ~9 ºC and ~20 ºC were detected between the electrode and battery surface in ESC and overcharge of small lab-fabricated Li-ion coin cells. The temperature difference can be as high as ~200 ºC for large capacity Li-ion pouch cells. In ESC, the internal RTD detected thermal runaway ~ 10 times faster than the external RTD despite of the battery type. Besides, the internal RTDs can provide accurate electrode temperature contour and comparison of anode and cathode temperatures during regular operation and thermal runaway of LIBs. The solid electrolyte interface (SEI) which is comprised of reduced electrolytic compounds like ROCO2Li, (CH2OCO2Li)2 and ROLi, can contribute to heat generation in LIB thermal runaway. The effect of SEI can be analyzed with in-situ examination of cathode and anode temperatures. Transient temperature difference captured by the internal RTD indicated that anode is the critical electrode and contributes more to the heat generated in thermal runaway. This helps to optimize temperature sensor arrangement for more effective monitoring and prevention of thermal runaway.The internal RTD also provides opportunity for in-situ analysis of chemical reactions in thermal runaway. Gas generated in thermal runaway has a high concentration of CO, H2, CH4, etc., which is prone to ignition and explosion. The generated gas can affect LIB structure as it causes deformation of electrodes and separators. Although this is hard to be detected with most basic BMS, it can be examined with electrode and battery surface temperature comparison, as the LIB thermal resistance is changed during gas accumulation. Different modes of thermal runaway can be differentiated by analyzing the temperature profiles, which allows for customized thermal runaway prevention and control strategy.

Hot-SWV: Square Wave Voltammetry with Hot Microelectrodes.

A promising strategy to lowering detection limits in electrochemical analysis is the active modulation of the electrode temperature. Specifically, by tuning the electrode's surface temperature one can enhance detection limits due to improved electrode process kinetics and increased mass transfer rates, all without affecting the bulk solution. Motivated by this argument, here we report the development of a new electroanalytical technique based on electrode-temperature modulation, which we call hot square wave voltammetry (Hot-SWV). The technique utilizes the superposition of conventional SWV, already considered as one of the most sensitive voltammetric techniques, and a high frequency alternating current (ac) waveform to electrically polarize microelectrodes. By applying about 100 MHz ac frequencies (with varying Vrms amplitudes), our method generates an electrothermal fluid flow (ETF) in the electrolyte surrounding the electrode, thereby increasing the sensitivity of the SWV-based detection. We demonstrate this by investigating the oxidation of ferrocyanide and iron(II) ions, as well as the reduction of the coordination compound ruthenium(III) hexamine under various experimental conditions. We validate our experimental results against a theoretical model built using finite element analysis and observe agreement within ≤15% error at temperatures ≤39 °C. Using Hot-SWV, we observe at least one-order-of-magnitude improvement in the limit of detection of ferrocyanide ions relative to conventional, mm-size electrodes at 25 °C. In addition, we anticipate that Hot-SWV will be particularly useful for electroanalytical measurements of ultralow (≤pM) concentrations of analytes in environmental and biomedical applications.

Enhancing Catalytic Activity and Selectivity by Plasmon-Induced Hot Carriers.

SummaryPlasmon-assisted chemical transformation holds great potential for solar energy conversion. However, simultaneous enhancement of reactivity and selectivity is still challenging and the mechanism remains mysterious. Herein, we elucidate the localized surface plasmon resonance (LSPR)-induced principles underlying the enhanced activity (∼70%) and selectivity of photoelectrocatalytic redox of nitrobenzene (NB) on Au nanoparticles. Hot carriers selectively accelerate the conversion rate from NB to phenylhydroxylamine (PHA) by ∼14% but suppress the transformation rate from PHA to nitrosobenzene (NSB) by ∼13%. By adding an electron accepter, the as-observed suppression ratio is substantially enlarged up to 43%. Our experiments, supported by in situ surface-enhanced Raman spectroscopy and density functional theory simulations, reveal such particular hot-carrier-induced selectivity is conjointly contributed by the accelerated hot electron transfer and the corresponding residual hot holes. This work will help expand the applications of renewable sunlight in the directional production of value-added chemicals under mild conditions.

Photothermal amplified cathodic ZnO quantum dots/Ru(bpy)32+/S2O82- ternary system for ultrasensitive electrochemiluminescence detection of thyroglobulin

Herein, an ultrasensitive electrochemiluminescence (ECL) immunosensor based on a high performance probe of Nb2CTx MXene immobilized ZnO quantum dots (QDs) was constructed for Thyroglobulin (Tg) detection. ZnO QDs with good biocompatibility and catalytic property was for the first time utilized as coreaction accelerator in Ru(bpy)32+/S2O82− system and enhanced ECL signal. Specifically, ZnO QDs can facilitate S2O82− reduction to generate more SO4−, and then reacted with cathodic radical of Ru(bpy)32+, realizing 2-fold enhancement in ECL intensity. Additionally, Nb2CTx MXene possesses excellent properties and was used as prominent supporter, improving the loading capacity of Ru(bpy)32+ and ZnO QDs, and accelerating the electron transfer, resulting in ECL signal enhancement. Furthermore, Nb2CTx MXene acted as temperature controller and increased the electrode surface temperature by converting laser energy into heat, further amplified ECL signal. Because of the high sensitivity, good specificity and favorable stability, the proposed immunosensor realized sensitive detection of Thyroglobulin and had a great application prospect in bioanalysis and clinical diagnosis.

Versatile NiCo2O4 nanosheets hybrids-based label-free immunosensor for thyroglobulin using photothermal amplification

Herein, an ultrasensitive label-free electrochemiluminescence (ECL) immunosensor based on electrocatalytic and photothermal amplification was constructed and was applied to detect Thyroglobulin (Tg). Single-walled carbon nanotube (SWCNTs) with charming merits was used as supporter for porous NiCo2O4 nanosheets (pNiCo2O4 NSs), the formed pNiCo2O4 NSs/SWCNTs hybrids was utilized as an effective matrix and realized multiple signal amplification. To be specific, pNiCo2O4 NSs/SWCNTs hybrids on the one hand can facilitate the electron transfer and enhance ECL signal. On the other hand can catalyze the oxygen evolution reaction (OER) to increase the concentration of dissolved O2 for further strengthening ECL signal. What’s more, the pNiCo2O4 NSs/SWCNTs hybrids had a strong near-infrared harvesting capability, can convert laser energy into heat to increase the electrode surface temperature, resulting in the significant enhancement in ECL signal. Based on excellent properties of pNiCo2O4 NSs/SWCNTs hybrids, a highly-efficient label-free ECL immunosensor was developed and exhibited a wide linear range (10−5 ng/mL to 100 ng/mL) and a low detection limit (3.3 × 10−6 ng/mL) for Tg determination, which was approximately 7.1 fold-lower than at room temperature. This work provided a new thought for high-performance ECL sensing platform construction.

Use of single needle high frequency irreversible electroporation (sn-hfire) to create reproducible pancreatic ablations in a survival swine model

Presenter: Patrick Salibi MD | Atrium Health Background: Irreversible electroporation (IRE) is an alternative to thermal ablation for treating unresectable pancreatic malignancies. However, IRE can be technically demanding due to the need to place multiple electrodes in an anatomically challenging environment, the risk of thermal damage to critical structures adjacent to the electrodes and extended intraoperative times (relative to thermal ablation). To address these limitations, we developed an experimental single needle-dual electrode high frequency IRE (SN-HFIRE) delivery system. The aim of this study was to evaluate the efficacy of SN-HFIRE in vivo by performing pancreatic ablations using different pulse delivery parameters designed to maintain ablation size while reducing the potential for thermal damage in a survival swine model. Methods: Under surgical anesthesia and ultrasound guidance, the SN-HFIRE device was placed in either the head or tail of the pancreas. Bipolar HFIRE pulses of 2,250 or 2,750V were delivered using a 2-5-2 pulse waveform (on-off-on time [μs]) as either a single contiguous series of pulse trains (CD; 2,250V, 1x100-bursts, 100μs on-time/burst), or four sets of 25 bursts (2,500V, 4x25-bursts, 60μs on-time/burst) with a 60sec delay between each set (DD). Intraoperative SN-HFIRE delivery was performed in the absence of paralytics or cardiac synchronization. Intraoperatively, tissue surface and electrode temperature were continuously measured along with physiological parameters (Chem-8), muscle movement, and cardiac output. Following SN-HFIRE delivery the laparotomy was closed and animals recovered and monitored for 3-days. At necropsy, tissue was collected and analyzed for ablation size, and ablation characteristics assessed histologically to identify areas of necrotic versus apoptotic cell death. Results: All animals (n=4) survived the procedures to experimental completion in the absence of detectable adverse events. Pancreatic SN-HFIRE device placement was achieved in less than 5mins and delivery of SN-HFIRE pulses was completed in 100secs (CD) versus 240sec (DD) (n=4 per group). No discernable muscle movement or cardiac events were detected during SN-HFIRE delivery for either CD or DD settings. Electrode surface temperature was significantly higher in CD versus DD (16.3+/-1.00C versus 6.5+/-0.60C) and translated to changes in measurement of tissue surface temperature (5.6+/-1.3 (CD) versus 0.3+/-0.50C [DD]). At necropsy, there were no abnormalities in the physiological parameters measured (Chem-8), and sites of ablation were readily identifiable prior to sectioning/staining. Following tissue staining (tetrazolium chloride) ablated regions demonstrated clearly defined boundaries of live-dead tissue from which measurements were used to calculate ablation volume. Using the CD approach mean ablation volume was 938+/-181mm3 versus 1044+/-208cm3 (DD). Histologically, H&E staining confirmed clear demarcation between ablated and healthy tissue, with a notable absence of infiltrating immune cells in both the CD and DD groups. Conclusion: SN-HFIRE allows the ability to rapidly create reproducible pancreatic ablations in vivo using a single-needle delivery device. The use of SN-HFIRE further simplifies intraoperative procedures and reduces pulse delivery time as it obviates the need for cardiac synchronization or intraoperative paralytics. Refining the pulse characteristics to include a delay between pulse train delivery significantly reduces the potential for thermal damage adjacent to the electrodes without compromising the ablation size that can be achieved.