Single-walled Carbon Nanotube Electrodes Research Articles

Dual-modified LiNi0.8Co0.1Mn0.1O2 cathode materials with lithium conducting hybrid oligomer and single-walled carbon nanotube for improving electrochemical performance and thermal stability of lithium-ion batteries: A novel approach for high-power and high-safety applications

In this study, we investigated the synergetic effect of a novel lithium-ion conducting hybrid oligomer [N, N′-bismaleimide-4, 4′-diphenylmethane (BMI), lithiated trithiocyanuric acid (Li-TCA) and Jeffamine®-M1000 (JA®); Li-BTJ] coating layer on a nickel-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material wrapped with highly electron-conductive single-walled carbon nanotubes (SWCNTs) to enhance electrochemical performance and thermal stability for high-power and high-safety lithium-ion batteries (LIBs). Morphological analyses using scanning electron microscopy/energy dispersive spectroscopy and transmission electron microscopy showed that the NCM811 active material surface was uniformly coated with a hybrid oligomer to form NCM811@Li-BTJ, which was subsequently wrapped with SWCNTs (NCM@Li-BTJ/SWCNT composite cathode). CR2032 coin-type cells with optimized NCM811@1 wt% Li-BTJ/0.2 wt% SWCNT composite electrodes delivered a significantly enhanced capacity retention (CR) of 90.1 % relative to that of bare NCM811 electrodes (CR: 82.1 %) at 1C for 200 cycles from 2.8 to 4.3 V (vs. Li/Li+). Electrochemical impedance spectroscopy and cyclic voltammetry revealed that this superior cycling performance resulted from a lower charge transfer resistance (Rct: 96.2 vs. 324.3 Ω) and a lower polarization voltage (∆V: 0.243 vs. 0.411 V vs. Li/Li+). The in-situ micro-calorimetric results presented the total heat generation (Qt) values of the coin cells with the delithiated NCM811@Li-BTJ and NCM@Li-BTJ/SWCNT electrodes at 5C and 35 °C were substantially lower by ~9.3 % and ~ 14.6 %, respectively, compared to the bare NCM811 counterpart, indicating that the surface modifications on the NCM811 active materials could prevent the LIBs' thermal instability. Furthermore, X-ray photoelectron spectroscopy studies revealed that the Li-BTJ hybrid oligomer coating layer effectively suppressed the formation of residual Li side products such as Li2CO3 evidently on the surface of the NCM811 active material particles, thereby inhibiting undesirable side reactions. Post-mortem analyses of the dual-modified NCM811 electrode after cycling revealed that the microstructure and particle morphology of the NCM composite cathode material were extensively maintained through the synergistic effects of the Li-BTJ ion-conductive and SWCNTs electron-conductive agents.

Self-Aligning Nanojunctions for Integrated Single-Molecule Circuits.

Robust, high-yield integration of nanoscale components such as graphene nanoribbons, nanoparticles, or single-molecules with conventional electronic circuits has proven to be challenging. This difficulty arises because the contacts to these nanoscale devices must be precisely fabricated with angstrom-level resolution to make reliable connections, and at manufacturing scales this cannot be achieved with even the highest-resolution lithographic tools. Here we introduce an approach that circumvents this issue by precisely creating nanometer-scale gaps between metallic carbon electrodes by using a self-aligning, solution-phase process, which allows facile integration with conventional electronic systems with yields approaching 50%. The electrode separation is controlled by covalently binding metallic single-walled carbon nanotube (mCNT) electrodes to individual DNA duplexes to create mCNT-DNA-mCNT nanojunctions, where the gap is precisely matched to the DNA length. These junctions are then integrated with top-down lithographic techniques to create single-molecule circuits that have electronic properties dominated by the DNA in the junction, have reproducible conductance values with low dispersion, and are stable and robust enough to be utilized as active, high-specificity electronic biosensors for dynamic single-molecule detection of specific oligonucleotides, such as those related to the SARS-CoV-2 genome. This scalable approach for high-yield integration of nanometer-scale devices will enable opportunities for manufacturing of hybrid electronic systems for a wide range of applications.

Double quantum dots in atomically-precise graphene nanoribbons

Bottom-up synthesized graphene nanoribbons (GNRs) are precise quantum materials, offering a high degree of tunability of their physical properties. While field-effect transistors and single quantum dot (QD) devices have been reported, the fabrication of double QD devices using GNRs remains challenging due to their nanometer-scale dimensions. In this study, we present a multi-gate double QD device based on atomically precise GNRs that are contacted by a pair of single-walled carbon nanotube electrodes. At low temperatures, the device can be tuned with multiple gates and reveals triangular features characteristic for charge transport through a double QD system. From these features, the QD level spacing, as well as the interdot tunnel coupling and lead-dot tunnel couplings are extracted. Double QD systems serve as essential building blocks for developing different types of qubits based on atomically precise GNRs.

Real-time selective detection of dopamine and serotonin at nanomolar concentration from complex in vitro systems

Electrochemical sensors provide means for real-time monitoring of neurotransmitter release events, which is a relatively easy process in simple electrolytes. However, this does not apply to in vitro environments. In cell culture media, competitively adsorbing molecules are present at concentrations up to 350 000-fold excess compared to the neurotransmitter-of-interest. Because detection of dopamine and serotonin requires direct adsorption of the analyte to electrode surface, a significant loss of sensitivity occurs when recording is performed in the in vitro environment. Despite these challenges, our single-walled carbon nanotube (SWCNT) sensor was capable of selectively measuring dopamine and serotonin from cell culture medium at nanomolar concentration in real-time. A primary midbrain culture was used to prove excellent biocompatibility of our SWCNT electrodes, which is a necessity for brain-on-a-chip models. Most importantly, our sensor was able to electrochemically record spontaneous transient activity from dopaminergic cell culture without altering the culture conditions, which has not been possible earlier. Drug discovery and development requires high-throughput screening of in vitro models, being hindered by the challenges in non-invasive characterization of complex neuronal models such as organoids. Our neurotransmitter sensors could be used for real-time monitoring of complex neuronal models, providing an alternative tool for their characterization non-invasively.

Manipulation of quantum spin transport of TM (Mn, Fe, Co, and Ni) (II) phthalocyanines coupled to carbon nanotube leads applicable in spintronic devices

We conducted a theoretical scrutiny on the quantum spin transport characteristics of a class of open-shell 3d-transition metal (TM = Mn, Fe, Co, and Ni) (II) phthalocyanines (TMPcs) molecules sandwiched between two semi-infinite armchair single-walled carbon nanotube probes. Herein, the spin density functional formalism is utilized in conjunction with state-of-the-art non-equilibrium Green's function technique. Molecular junctions composed of MnPc and FePc have higher local magnetic spin moments than CoPc and NiPc because of the strong exchange spin-splitting between the 3d-states of the Mn or Fe cation atoms and the p-states of the N anion atom. This indicates that TMPc molecules (TM = Mn, and Fe) bridged between two single-walled carbon nanotube (SWCNT) electrodes with a π-type geometry demonstrate a pronounced transmission near the Fermi level. Furthermore, the sign and robustness of spin filter efficiency are tailored by manipulating the central atom of 3d-transition metal and the contact SWCNT electrodes. Subsequently, FePc and MnPc molecular junctions have the advantage of operating practically as ideal spin filter devices compared to CoPc and NiPc molecular structures. Moreover, the tunneling magnetoresistance (TMR) of these molecular devices is assessed. For MnPc and FePc molecular junctions, the estimated total conductance exhibited a robust trend at zero bias voltage, whereas the magnitudes of spin-up and spin-dn quantum conductances increased significantly in CoPc and NiPc molecular configurations with bias voltages range between ±0.45 and ±0.95 Volt. Spin-down carriers essentially govern the quantum conductance of TMPc (Mn, Fe, Co, and Ni) molecular junctions at bias voltage around ±0.75 Volt. By examining their I-V characteristics, it has been established that MnPc, and FePc molecular junctions exhibit metal-like behavior, whereas CoPc and NiPc molecular devices are subject to negative differential resistance. As a result of our theoretical findings, it is found that TMPcs (TM = Fe, Mn) coupled to SWCNT probes yield a robust spin filter efficiency that may be of interest for prospective technological realizations in organic-inorganic molecular spintronic devices.

Remarkable modulation of the spin transport properties of transition metal dibenzotetraaza[14]annulenes by adsorption of oxygen

Here, the spin transport properties of molecular devices comprised of a transition metal-dibenzotetraaza[14]annulene complex (TM-DBTAA, TM=Co, Cu, Ni) connected to two single-walled carbon nanotube (SWCNT) electrodes have been theoretically investigated by using the first-principles method. In addition, the effect of O2 adsorption on the TM atom on the spin transport properties of the investigated devices is inspected. The calculations reveal that Co-DBTAA behaves as a spin filter with SFE close to 100%. Upon O2 adsorption, the spin polarization of the current for Co-DBTAA is changed from spin-down to spin-up with the magnitude of SFE nearly unchanged. More interestingly, for the spin non-polarized and nonconducting Ni-DBTAA, the adsorption of an O2 molecule induces a spin-up polarized current with remarkable SFE larger than 90%. This work is helpful for future designing of molecular spin filters as well as gas sensors.

Electroanalytical biosensor based on GOx/FCA/PEG-modified SWCNT electrode for determination of glucose

This paper describes a simple electrochemical sensing platform based on single-walled carbon nanotube (SWCNT) electrodes for glucose detection. The device fabrication using O2-plasma treatment allows precision and uniformity for the construction of three SWCNT electrodes on the flexible plastic substrate. Glucose assay can be simply accomplished by introducing a glucose sample into the fabricated biosensor. The marked electrocatalytic and biocompatible properties of biosensors based on SWCNT electrodes with the incorporation of ferrocenecarboxylic acid and polyethylene glycol enable effective amperometric measurement of glucose at a low oxidation potential (0.3 V) with low interferences from coexisting species. The device shows efficient electroanalytical performances with high sensitivity (5.5 μA·mM−1·cm−2), good reproducibility (CV less than 3%), and long-term stability (over a month). A linear range of response was found from 0 to 10 mM of glucose with a fast response time of 10 s. This attractive electroanalytical device based on GOx/FCA/PEG/SWCNT electrodes offers a promising system to facilitate a new approach for diverse biosensors and electrochemical devices.

Nitrate detection at Pd-Cu-modified carbon screen printed electrodes

Carbon nanofibers (CNF) and single-walled carbon nanotubes (SWCNT) screen printed electrodes (SPEs) are used for bi-metal, Pd-Cu, modification. Pd nanoparticles (NPs) are deposited first on the pre-reduced carbon SPEs by means of a spontaneous electroless process in the absence of solute reductants. Copper is deposited in a next step under galavanostatic conditions. For both electrodes the Pd deposit consists of NPs with sizes in the 10-ths of nm range with a much denser population and larger amount of the metallic phase in the SWCNT case. The copper deposit on the Pd-modified SPEs differs markedly depending on the type of the underlying substrate with a three times larger mass ratio Pd/Cu of the deposited metals for the SWCNT electrode compared to the CNF one. Nitrate detection is studied on the Cu- and Pd-Cu-modified electrodes in slightly acidic sulfate solution by means of linear sweep voltammetry. The comparison of the mono- and bi-metal- modified electrodes shows a significant enhancement of the nitrate-related reductive currents at the Pd-Cu-modified carbon SPEs. Between the two bi-metal modified electrodes the SWCNT-based one has a higher sensitivity and a larger concentration range of reproducible electroanalytical signal. The non-linear concentration dependence of the nitrate reduction peak currents is modeled by means of a Langmuir type of equation and used for recovery measurements. The Pd-Cu-modified SWCNT-based SPE shows a good stability of the metallic phases over extended nitrate reduction measurements series.

Electrochemical impedance spectroscopy analysis of plasma-treated, spray-coated single-walled carbon-nanotube film electrodes for chemical and electrochemical devices

In this study, carbon-nanotube (CNT) surfaces were treated with oxygen plasma, and the improvement in surface inertness was analyzed using electrochemical impedance spectroscopy (EIS). Among nanomaterials, CNTs are the most attractive owing to their outstanding properties. However, the chemical inertness of CNT surfaces hinders the widespread implementation of CNTs in bioanalytical applications. Therefore, we present in detail the electrochemical properties of CNTs treated in various plasma conditions. The single-walled carbon nanotube (SWCNT) films were spray-coated onto working electrodes with a three-electrode configuration fabricated on a glass substrate and activated at various plasma conditions. The EIS spectra of the SWCNT film revealed typical porous structure characteristics. As the thickness of the SWCNT film increased by spray coating, the charge-transfer resistance sharply increased owing to the reduction of the effective electrode area caused by the decreased roughness and porosity of the SWCNT film. The Nyquist plots of the plasma-treated SWCNT electrodes featured two semicircular regions at high and intermediate frequencies, as well as one straight line at low frequencies. The plasma-treated SWCNT electrode had a less distinct separation of the second arc and straight line than the untreated SWCNT electrode because the time constant was lowered owing to the diffusion process generated where the charge-transfer reaction occurred. We analyzed the change in the electrodes through EIS, which can identify individual contributions to the total impedance of an electrochemical system.

Spiro-OMeTAD versus PTAA for single-walled carbon nanotubes electrode in perovskite solar cells

Poly(triarylamine) (PTAA)-wrapped single-walled carbon nanotubes (SWCNTs) functioned in a dual role as an efficient hole-transporting layer and electrode in perovskite solar cells (PSCs). Thanks to the well-matched energy level, increased hole-transporting mobility, and hydrophobicity rendered by dopant-free PTAA, this dual-role SWCNTs electrode applied-PSCs using dopant-free PTAA achieved a better efficiency and stability than reference standards using LiTFSI-doped Spiro-OMeTAD. This dopant-free PTAA-applied SWCNTs electrode is expected to not only give a solution for efficiently using the SWCNTs electrode in PSCs, but also unveil the mechanism of the interaction between the hole-transporting layer and SWCNTs.

Highly Sensitive MoS2 Photodetectors Enabled with a Dry-Transferred Transparent Carbon Nanotube Electrode.

Fabricating electronic and optoelectronic devices by transferring pre-deposited metal electrodes has attracted considerable attention, owing to the improved device performance. However, the pre-deposited metal electrode typically involves complex fabrication procedures. Here, we introduce our facile electrode fabrication process which is free of lithography, lift-off, and reactive ion etching by directly press-transferring a single-walled carbon nanotube (SWCNT) film. We fabricated Schottky diodes for photodetector applications using dry-transferred SWCNT films as the transparent electrode to increase light absorption in photoactive MoS2 channels. The MoS2 flake vertically stacked with an SWCNT electrode can exhibit excellent photodetection performance with a responsivity of ∼2.01 × 103 A/W and a detectivity of ∼3.2 × 1012 Jones. Additionally, we carried out temperature-dependent current-voltage measurement and Fowler-Nordheim (FN) plot analysis to explore the dominant charge transport mechanism. The enhanced photodetection in the vertical configuration is found to be attributed to the FN tunneling and internal photoemission of charge carriers excited from indium tin oxide across the MoS2 layer. Our study provides a novel concept of using a photoactive MoS2 layer as a tunneling layer itself with a dry-transferred transparent SWCNT electrode for high-performance and energy-efficient optoelectronic devices.

One-dimensional semimetal contacts to two-dimensional semiconductors

Two-dimensional (2D) semiconductors are promising in channel length scaling of field-effect transistors (FETs) due to their excellent gate electrostatics. However, scaling of their contact length still remains a significant challenge because of the sharply raised contact resistance and the deteriorated metal conductivity at nanoscale. Here, we construct a 1D semimetal-2D semiconductor contact by employing single-walled carbon nanotube electrodes, which can push the contact length into the sub-2 nm region. Such 1D–2D heterostructures exhibit smaller van der Waals gaps than the 2D–2D ones, while the Schottky barrier height can be effectively tuned via gate potential to achieve Ohmic contact. We propose a longitudinal transmission line model for analyzing the potential and current distribution of devices in short contact limit, and use it to extract the 1D–2D contact resistivity which is as low as 10−6 Ω·cm2 for the ultra-short contacts. We further demonstrate that the semimetal nanotubes with gate-tunable work function could form good contacts to various 2D semiconductors including MoS2, WS2 and WSe2. The study on 1D semimetal contact provides a basis for further miniaturization of nanoelectronics in the future.

Effects of ambient air on functional stability of single-molecule spin logic gate

Single-molecule spin logic gates provide fundamental functions and are of importance in the field of molecular spintronics. Here, by using the firstprinciples method, the effects of ambient gas molecules (CO2, O2, N2, or H2O) on the functional stability of the investigated single-molecule spin logic gate consisting of two serially connected cobalt dibenzotetraaza[14]annulene (CoDBTAA) molecules between single-walled carbon nanotubes (SWCNTs) electrodes, have been theoretically investigated. The calculated results suggest that the investigated spin logic gate can realize AND, NOR, or XNOR logic functions depending on the definition of the input and output signals. It is found that these logic functions are not affected by CO2 adsorption. On the contrary, these logic functions are no longer retained upon O2, N2, or H2O adsorption. Further analysis reveals that the interaction between the CoDBTAA molecule and the CO2 adsorbate is very weak while it is strong for O2, N2, or H2O molecules. Therefore, the electronic states of the logic gate around Fermi energy (EF) are almost unchanged for CO2 adsorption. While the adsorption of O2, N2, or H2O obviously modifies the electronic states around EF. The strong interaction between CoDBTAA and these three gas adsorbates drives the conductive electronic states to move far away from EF, resulting in the blocking of both spin-up and spin-down currents and further voiding the logic functions. This work suggests that ambient air has an important effect on the functional stability of single-molecule devices and should be carefully evaluated in the future design of functional single-molecule devices.

Ascorbic acid does not necessarily interfere with the electrochemical detection of dopamine

It is widely stated that ascorbic acid (AA) interferes with the electrochemical detection of neurotransmitters, especially dopamine, because of their overlapping oxidation potentials on typical electrode materials. As the concentration of AA is several orders of magnitude higher than the concentration of neurotransmitters, detection of neurotransmitters is difficult in the presence of AA and requires either highly stable AA concentration or highly selective neurotransmitter sensors. In contrast to the common opinion, we show that AA does not always interfere electrochemical detection of neurotransmitters. The decay of AA is rapid in cell culture medium, having a half-time of 2.1 hours, according to which the concentration decreases by 93% in 8 hours and by 99.75% in 18 hours. Thus, AA is eventually no longer detected by electrodes and the concentration of neurotransmitters can be effectively monitored. To validate this claim, we used unmodified single-wall carbon nanotube electrode to measure dopamine at physiologically relevant concentration range (25–1000 nM) from human midbrain organoid medium with highly linear response. Finally, AA is known to affect dopamine oxidation current through regeneration of dopamine, which complicates precise detection of small amounts of dopamine. By designing experiments as described here, this complication can be completely eliminated.

Ultralow-Power and Miniaturized X-ray Sensor Using the Single-Walled Carbon Nanotube Micro Network-Based Geiger Counter Design

We present an ultralow-power, highly sensitive, and miniaturized X-ray sensor with micropatterned single-walled carbon nanotube (SWCNT) interdigitated networks inspired by the Geiger-Mueller counter design. Due to the unique nanostructured surface and superb electronic transport nature of assembled SWCNTs, a strong electric field is formed between and within highly organized SWCNT interdigitated electrodes, which effectively separates electrons and ionized ions created by incident X-rays into electrodes, facilitating electron detection. As a result, the device can detect a low X-ray dose rate (9.97 μGy·s–1) with an extremely low power consumption of 80–90 fW, demonstrating a sensitivity of up to 203.96 μC·Gy–1·cm–2. Furthermore, the interdigitated SWCNT electrode design produces a low noise level in the picoampere range, permitting exceptional real-time signal detection during X-ray exposure. These unique features of our SWCNT X-ray sensing device enable various low SWaP (size, weight, and power) radiation detectors in the fields of medicine, homeland security, and defense.

Non-noble metal FeMn and single-walled carbon nanotubes nanocomposites as effective bifunctional electrocatalysts in alkaline media for oxygen/hydrogen revolution reactions

Single-walled carbon nanotubes (SWCNTs) are one of electrochemical materials with excellent electrical properties. Herein, we design the new FeMn x /SWCNTs nanocomposites which are synthesized in one step by the direct current (DC) arc discharge method. The overpotentials of oxygen/hydrogen revolution reactions of FeMn 1 /SWCNTs electrodes in alkaline solution are 190 and 317 mV respectively when the current density reaches 10 mA cm −2 . The synergistic effect between FeMn compounds and single-walled carbon nanotubes can not only increase the active sites of the composites, but also optimize the electronic structure of the composites, thereby significantly improving the OER and HER performance of the materials. This work provides an idea that the composites of SWCNTs and bimetallic hybrids have excellent electrocatalytic performance.

Controlling Dynamic DNA Reactions at the Surface of Single-Walled Carbon Nanotube Electrodes to Design Hybridization Platforms with a Specific Amperometric Readout.

Carbon nanotube (CNT)-based electrodes are cheap, highly performing, and robust platforms for the fabrication of electrochemical sensors. Engineering programmable DNA nanotechnologies on the CNT surface can support the construction of new electrochemical DNA sensors providing an amperometric output in response to biomolecular recognition. This is a significant challenge, since it requires gaining control of specific hybridization processes and functional DNA systems at the interface, while limiting DNA physisorption on the electrode surface, which contributes to nonspecific signal. In this study, we provide design rules to program dynamic DNA structures at the surface of single-walled carbon nanotubes electrodes, showing that specific DNA interactions can be monitored through measurement of the current signal provided by redox-tagged DNA strands. We propose the use of pyrene as a backfilling agent to reduce nonspecific adsorption of reporter DNA strands and demonstrate the controlled formation of DNA duplexes on the electrode surface, which we then apply in the design and conduction of programmable DNA strand displacement reactions. Expanding on this aspect, we report the development of novel amperometric hybridization platforms based on artificial DNA structures templated by the small molecule melamine. These platforms enable dynamic strand exchange reactions orthogonal to conventional toehold-mediated strand displacement and may support new strategies in electrochemical sensing of biomolecular targets, combining the physicochemical properties of nanostructured carbon-based materials with programmable nucleic acid hybridization.

Disposable carbon nanotube-based antifouling electrochemical sensors for detection of morphine in unprocessed coffee and milk

The direct on-site detection of illegal additives in unprocessed food samples is usually a great challenge for electrochemical sensors because of electrode biofouling. In this work, a simple filtration method for the scalable fabrication of disposable single-walled carbon nanotubes (SWCNTs)-based antifouling electrochemical sensors is reported. This method employs flash foam stamp-assisted polydimethylsiloxane (PDMS) patterns to control the region-selective deposition of SWCNTs on polyvinylidene fluoride (PVDF) membranes during filtration, which enables the scalable fabrication of a SWCNTs three-electrode-based sensor with high conductivity, good reproducibility and excellent flexibility. The resulting SWCNTs sensor exhibits a sensitive response towards morphine with a calibration range of 0.2 ∼ 100 μg mL−1 and a detection limit of 0.06 μg mL−1 (S/N = 3). Moreover, probably owing to its unique nanoporous structure, this SWCNTs sensor possesses apparently improved antifouling ability as compared with the widely used glassy carbon electrode (GCE), and allows the direct detection of morphine in unprocessed complex foods such as milk and coffee. The present work thus establishes a simple approach to the scalable production of self-designed SWCNTs electrode arrays suitable for on-site food analysis, which may also provide an alternative to commercial screen-printed carbon electrodes (SPCEs) for electrochemical sensing applications.

Theoretical design of thermal spin molecular logic gates by using a combinational molecular junction

Based on the density functional theory combined with the nonequilibrium Green function methodology, we have studied the thermally-driven spin-dependent transport properties of a combinational molecular junction consisting of a planar four-coordinate Fe molecule and a 15,16-dinitrile dihydropyrene/cyclophanediene molecule, with single-walled carbon nanotube bridge and electrode. Our results show that the magnetic field and light can effectively regulate the thermally-driven spin-dependent currents. Perfect thermal spin-filtering effect and good thermal switching effect are realized. The results are explained by the Fermi–Dirac distribution function, the spin-resolved transmission spectra, the spatial distribution of molecular projected self-consistent Hamiltonian orbitals, and the spin-resolved current spectra. On the basis of these thermally-driven spin-dependent transport properties, we have further designed three basic thermal spin molecular AND, OR, and NOT gates.

In vitro enzymatic electrochemical monitoring of glucose metabolism and production in rat primary hepatocytes on highly O2 permeable plates

In situ continuous glucose monitoring under physiological culture conditions is imperative in understanding the dynamics of cell and tissue behaviors and their physiological responses since glucose plays an important role in principal source of biological energy. We therefore examined physiologically relevant dynamic changes in glucose levels based on glucose metabolism and production during aerobic culture (10% O2) of rat primary hepatocytes stimulated with insulin or glucagon on a highly O2 permeable plate, which can maintain the oxygen concentration close to the periportal zone of the liver. As glucose monitoring devices, we used oxygen-independent glucose dehydrogenase-modified single-walled carbon nanotube electrodes placed close to the surface of the hepatocytes. The current response of glucose oxidation slightly decreased after the addition of insulin in the presence of glucose due to the acceleration of glucose uptake by the hepatocytes, whereas that significantly increased after the addition of glucagon and fructose even in the absence of glucose due to the conversion of fructose to glucose based on gluconeogenesis. These phenomena might be consistent relatively with the physiological behaviors of hepatocytes in the periportal region. The present monitoring system would be useful for the studies of glucose homeostasis and diabetes in vitro.