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Organs-on-a-chip (OoC) are cell culture platforms that replicate key functional units of tissues in vitro. Barrier integrity and permeability evaluation are of utmost importance when studying barrier-forming tissues. Impedance spe...
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Organs-on-a-chip (OoC) are cell culture platforms that replicate key functional units of tissues in vitro. Barrier integrity and permeability evaluation are of utmost importance when studying barrier-forming tissues. Impedance spectroscopy is a powerful tool and is widely used to monitor barrier permeability and integrity in real-time. However, data comparison across devices is misleading due to the generation of a non-homogenous field across the tissue barrier, making impedance data normalization very challenging. In this work, we address this issue by integrating PEDOT:PSS electrodes for barrier function monitoring with impedance spectroscopy. The semitransparent PEDOT:PSS electrodes cover the entire cell culture membrane providing a homogenous electric field across the entire membrane making the cell culture area equally accountable to the measured impedance. To the best of our knowledge, PEDOT:PSS has never been used solely to monitor the impedance of cellular barriers while enabling optical inspection in the OoC. The performance of the device is demonstrated by lining the device with intestinal cells where we monitored barrier formation under flow conditions, as well as barrier disruption and recovery under exposure to a permeability enhancer. The barrier tightness and integrity, and the intercellular cleft have been evaluated by analyzing the full impedance spectrum. Furthermore, the device is autoclavable paving the way toward more sustainable OoC options.
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Correction for ‘Organ-on-a-chip with integrated semitransparent organic electrodes for barrier function monitoring’ by Denise Marrero et al., Lab Chip, 2023, https://doi.org/10.1039/d2lc01097f.
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? 2023 The AuthorsThe early detection of very low bacterial concentrations is key to minimize the healthcare and safety issues associated with microbial infections, food poisoning or water pollution. In amperometric integrated cir...
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? 2023 The AuthorsThe early detection of very low bacterial concentrations is key to minimize the healthcare and safety issues associated with microbial infections, food poisoning or water pollution. In amperometric integrated circuits for electrochemical sensors, flicker noise is still the main bottleneck to achieve ultrasensitive detection with small footprint, cost-effective and ultra-low power instrumentation. Current strategies rely on autozeroing or chopper stabilization causing negative impacts on chip size and power consumption. This work presents a 27-μW potentiostatic-amperometric Delta-Sigma modulator able to cancel its own flicker noise and provide a 4-fold improvement in the limit of detection. The 2.3-mm2 all-in-one CMOS integrated circuit is glued to an inkjet-printed electrochemical sensor. Measurements show that the limit of detection is 15 pArms, the extended dynamic range reaches 110 dB and linearity is R2 = 0.998. The disposable device is able to detect, in less than 1h, live bacterial concentrations as low as 102 CFU/mL from a 50-μL droplet sample, which is equivalent to 5 microorganisms.
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Flexible gas sensor devices comprised of heating and transducing elements are produced by directly integrating multilayer polymeric-based platforms and highly crystalline semiconducting metal oxide nanostructures grown via vapour-...
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Flexible gas sensor devices comprised of heating and transducing elements are produced by directly integrating multilayer polymeric-based platforms and highly crystalline semiconducting metal oxide nanostructures grown via vapour-phase method, as main improvement over other methods for fabricating flexible gas sensors. Thermal simulations and characterizations of the heating element demonstrate these devices provide uniform temperature distribution at the sensing active area, and the electrical properties of the sensing film and electrodes indicate the networked-nanostructures are ohmically connected. Validation of the sensing device shows repeatable and satisfactory responses towards ethanol, demonstrating this fabrication method, with potential in a cost effective production for large-scale applications, is an attractive route for developing next generation of gas sensing devices provided of flexibility and functionality.
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The fabrication of CMOS devices in SiC is important for both a higher operating temperature capability and the integration with SiC power devices. In this work, n-channel and p-channel signal MOSFETs have been successfully fabrica...
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The fabrication of CMOS devices in SiC is important for both a higher operating temperature capability and the integration with SiC power devices. In this work, n-channel and p-channel signal MOSFETs have been successfully fabricated using a process technology fully compatible with our HV SiC VDMOS technology. A preliminary SiC CMOS inverter has been also integrated. The gate oxide configuration includes the use of Boron to improve SiO<sub>2</sub>/SiC. Electrical characterizations have been carried out at room temperature and a summary of the results is presented. The biggest challenge is to balance the n-type and p-type MOSFETs not only in area but also in V<sub>th</sub> value.
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A new vertical JFET technology, based on a 3D trenched design, has been developed at the IMB-CNM. These transistors are conceived to work as rad-hard protection switches in the renewed High Voltage powering scheme for the Upgrade ...
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A new vertical JFET technology, based on a 3D trenched design, has been developed at the IMB-CNM. These transistors are conceived to work as rad-hard protection switches in the renewed High Voltage powering scheme for the Upgrade ATLAS ITk strip detectors. The first fabricated wafers have been fully characterized and the V-JFET performance is very close to the required specifications, showing excellent agreement with simulations. In thiswork the performance of the fabricated prototypes is tested under harsh ionizing radiation conditions. The variation of the main figures of merit is evaluated as a function of the Total Ionising Dose (TID) and the impact of different design parameters and fabrication strategies are compared. A final study, performed with the aid of TCAD simulations, is also included to understand the effects of the ionization damage observed on the V-JFET performance.
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? 2021 The AuthorsNeuroelectronic interfaces with the nervous system are an essential technology in state-of-the-art neuroscience research aiming to uncover the fundamental working mechanisms of the brain. Progress towards increas...
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? 2021 The AuthorsNeuroelectronic interfaces with the nervous system are an essential technology in state-of-the-art neuroscience research aiming to uncover the fundamental working mechanisms of the brain. Progress towards increased spatio-temporal resolution has been tightly linked to the advance of microelectronics technology and novel materials. Translation of these technologies to neuroscience has resulted in multichannel neural probes and acquisition systems enabling the recording of brain signals using thousands of channels. This review provides an overview of state-of-the-art neuroelectronic technologies, with emphasis on recording site architectures which enable the implementation of addressable arrays for high-channel-count neural interfaces. In this field, active transduction mechanisms are gaining importance fueled by novel materials, as they facilitate the implementation of high density addressable arrays.
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In this work, we study the electrochemical behaviour of skatole, one of the compounds responsible for the offensive smell in pork meat that is known as boar taint, at different metal and carbon electrodes. We then demonstrate for ...
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In this work, we study the electrochemical behaviour of skatole, one of the compounds responsible for the offensive smell in pork meat that is known as boar taint, at different metal and carbon electrodes. We then demonstrate for the first time that skatole and indole, the main electroactive interferent potentially present in real samples, can be discriminated and separately quantified using cheap and disposable screen printed electrodes (SPE). This implies significant progress compared to the colorimetric method reported by Mortensen in 1983.
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Carbon nanotubes (CNT) have been exploited for an important number of electroanalytical and sensing purposes. Specifically, CNT incorporation to an electrode surface coating increases its roughness and area, provides electrocataly...
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Carbon nanotubes (CNT) have been exploited for an important number of electroanalytical and sensing purposes. Specifically, CNT incorporation to an electrode surface coating increases its roughness and area, provides electrocatalytic activity towards a variety of molecules, and improves electron transfer. This modification is generally based on the irreversible deposition of CNT on surface. Nevertheless, CNT are highly porous materials that might promote molecule non-specific adsorption and/or electrodeposition, which could induce sample-to-sample cross-contamination and affect measurement specificity and reproducibility. This drawback has been often circumvented by combining CNT with charged polymers able to repel molecules of opposed charge.We demonstrate that single-walled CNT (SWCNT) have a strong tendency to non-specifically adsorb onto the surface of protein-coated magnetic particles (MP). Magnetic capture of those MP generates CNT coentrapment and allows extremely fast, simple and reversible production of SWCNT electrodes. We have exploited this phenomenon for the production of modified screen-printed electrodes (MP/CNT-SPE), which have been characterized by Scanning Electron Microscopy. The surface has been additionally optimized by evaluating the electrochemical performance of SPE modified with different amounts and proportions of MP and CNT. The modified devices have then been used for dopamine detection. MP/CNT-SPE generated improved assay sensitivity, lower limit of detection, and up to 500% higher current signals than bare electrodes. Magnetic entrapment is proposed as a promising strategy for the fast, simple and reversible generation of nanostructured electrodes of enhanced performance within a few minutes and electrode re-utilisation by simple magnet removal and surface washing.
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Microdevices are fractured at specific sites to fabricate free-standing multilayered submicrometer structures, which consist of the microdevice cross sections that become exposed after fracture. As determined by finite-element mod...
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Microdevices are fractured at specific sites to fabricate free-standing multilayered submicrometer structures, which consist of the microdevice cross sections that become exposed after fracture. As determined by finite-element modeling, the microdevices feature a fracturing point where stress concentrates under applied pulling forces. The structures fabricated here have a core of phosphosilicate glass surrounded by a layer of polycrystalline silicon.
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