Integrated Graphene’s latest Publications

• IL10 acts as a gene regulator with functions encompass the suppression and termination of inflammatory immune responses.

• Monitoring Interleukin 10 (IL-10) is essential for understanding the vast responses of T-cells in cancer, autoimmunity, and internal homeostasis after physical stress. However, current diagnostic methods are complex and more focused on medical screening rather than point-of-care monitoring.

• IL-10 is usually assayed using commercially available ELISA kits and its expression is evaluated through real-time PCR. All these techniques are reported as fast and straightforward; however, their sample preparation protocols are complex, not to mention the unique infrastructure and personnel requirements needed to perform them.

• You can maintain the benefits of our biosensors conductivity and flexibility without compromising on conductivity by employing π–π non-covalent functionalization with pyrene carboxylic acid (PCA) in a microfluidic chip.

• Adopting biosensors in clinical applications can shorten the response time of primary health services. However, the development of automated single-use biosensors is desired to offer widespread point-of-care monitoring and that’s where our Gii-Sens can be utilised. Finally, this approach reduced handling, and simple measuring achieved detection limits in the order of femtograms per millilitre.

Frias, I.A., Zine, N., Sigaud, M., Lozano-Sanchez, P., Caffio, M. and Errachid, A., 2023. Non-covalent π–π functionalized Gii-senseⓇ graphene foam for interleukin 10 impedimetric detection. Biosensors and Bioelectronics, 222, p.114954.

• Abnormal blood lactate concentrations resulting from conditions such as sepsis can be difficult to identify and diagnose in critically ill patients.

• Therefore, reliable real-time lactate detection through single-point or continuous sensing could be advantageous to outcomes in ICU care or during intensive surgery, and early detection could reduce acidosis mortality rates among critically ill patients. To realise this, low cost, reliable sensing methods capable of accurately detecting lactate in serum or blood without interference from other species present are required.

• Multiple experiments were performed with the same modified electrode with only minimal loss of sensing performance indicating the robustness of our product.

• The experiment successfully shows that we can successfully perform a polymer indicator displacement assay using our Gii-Sens platform.

• Gii-Sens can help to move benchtop devices to point of care as required in the application of such assays given it’s low cost and reliable.

Wikeley, S.M., Lozano-Sanchez, P., Caffio, M., James, T.D. and Marken, F., 2023. Polymer indicator displacement assay (PIDA) with boronic acid receptors on graphene foam electrodes for self-optimised impedimetric lactic acid determination. Sensors and Actuators B: Chemical, 377, p.133089.

• The goal of this paper was to catalyse a reaction whereby the polymer coating absorbs oxygen to enhance hydrogen peroxide production using Gii-Sens.

• Graphene and graphene-oxide-related materials have been shown to be active in producing hydrogen peroxide cathodically but the yield of H2O2 may vary, dependent on conditions, defects, or doping.

• Here, it is demonstrated that the formation of H2O2 on graphene foam can be enhanced by microporous polymer deposits on the Gii electrode surface.

Beluomini, M.A., Wang, Y., Wang, L., Carta, M., McKeown, N.B., Wikeley, S.M., James, T.D., Lozano-Sanchez, P., Caffio, M., Stradiotto, N.R. and Zanoni, M.V.B., 2022. Polymer of intrinsic microporosity (PIM-1) enhances hydrogen peroxide production at Gii-Sens graphene foam electrodes. Electrochemistry Communications, 143, p.107394.

• Successful diabetes management relies upon accurate and sensitive blood glucose testing methods to inform insulin dosage. However, enzyme-based biosensors are inherently affected by changes in temperature, pH and are dependent on localised oxygen concentration in the analyte, which can lead to reliability issues and may impact upon the ability of the patient to effectively manage their condition. Furthermore, current electrochemical glucose sensors on the market today are expensive.

• Here, we propose an alternative, low-cost yet effective electrochemical glucose chemo-sensing technique based on a boronic acid functionalisation upon Gii-Sens.

• The new methodology is shown to give apparent saccharide – boronic acid binding constants and to work in human serum, this shows in the future that this could be developed further to develop a glucose monitoring method.

Wikeley, S, Przybylowski, J, Lozano-Sanchez , P, Caffio , M, James, T, Bull, S, Fletcher, P & Marken, F 2022, 'Polymer Indicator Displacement Assay: Electrochemical Glucose Monitoring Based on Boronic Acid Receptors and Graphene Foam Competitively Binding with Poly-Nordihydroguaiaretic Acid', The Analyst, vol. 147, no. 4, pp. 661-670. https://doi.org/10.1039/d1an01991k

• Pressure sensors are widely used devices in a variety of sectors from automotive, medical, industrial and consumer devices.

• Currently flexible pressure sensors are primarily based on capacitive, resistive and piezoelectric methods.

• Advanced materials such as Gii has been proposed as a promising material due to enhanced electric properties (fast device response, low recovery time and low power consumption), mechanical properties (high durability, conformability) providing compatibility with flexible substrates.

• NAs the sensors are still in the initial fabrication process more data needs to be collected and analyzed to fully understand the exciting implications these sensors can provide for a variety of industries.

Douglas, C.I., Nuñez, C.G., Caffio, M. and Gibson, D., 2022. Ultra-Thin Graphene Foam Based Flexible Piezoresistive Pressure Sensors for Robotics. In Key Engineering Materials (Vol. 922, pp. 79-86). Trans Tech Publications Ltd.

• Part 2 of the “Ultra-Thin Grapheen Foam Based Flexible Piezoresistive Pressure Sensors for Robotics

• Pressure sensors are widely used devices in a variety of sectors from automotive, medical, industrial and consumer devices.

• Currently flexible pressure sensors are primarily based on capacitive, resistive and piezoelectric methods.

• Advanced materials such as Gii has been proposed as a promising material due to enhanced electric properties (fast device response, low recovery time and low power consumption), mechanical properties (high durability, conformability) providing compatibility with flexible substrates.

• NAs the sensors are still in the initial fabrication process more data needs to be collected and analyzed to fully understand the exciting implications these sensors can provide for a variety of industries.

Douglas, C.I., Nuñez, C.G., Gibson, D. and Caffio, M., 2021, June. Development of flexible and high sensitivity graphene foam based pressure sensors. In 2021 13th Spanish Conference on Electron Devices (CDE) (pp. 141-144). IEEE.

Abstract

In this work we investigate the potential of three-dimensional graphene (3DG) foam as an active layer in triboelectric nanogenerators (TENGs) and as an energy harvesting power source for autonomous sensors. A series of comprehensive measurements have been carried out to test the output characteristics of 3DG-TENG under cyclic mechanical stimulus, capable of operating TENG in contact-separation mode at different frequencies, gap distances between electrodes, and applied pressures. The triboelectric response of 3DG-TENG (with an effective surface of 16 cm2) showed maximum open-circuit voltage (Voc) and short-circuit current (Isc) of 400 V and 105.7 μA respectively when stimulated at 3 Hz (contact-separation frequency) and 70 mm (optimum gap distance). Under the same conditions, a maximum output power (Pout) of around 10.37 W/m2 is produced using an external load resistance of 40 MΩ; this is an order of magnitude lower resistance than that needed with other graphene based TENG variants. 3DG-TENG exhibited great stability in the output characteristics with 15,000 cyclic mechanical stimuli and a retention percentage in Pout above 95%. This is a significant improvement with respect to other carbon based TENG`s, which show enhanced deterioration of TENG performance due to material transfer between electrodes and plastic deformation of triboelectric materials. Simulations of TENG Voc using distance dependent model determined high triboelectric charge densities in the range of mC/m2. Here, we also demonstrate the potential of 3DG-TENG as an energy supply for energy storage devices, and as an active layer in an autonomous pressure sensing platform for anonymous room occupancy monitoring in smart buildings.

Emma Keel, Ammara Ejaz, Michael Mckinlay, Manuel Pelayo Garcia, Marco Caffio, Des Gibson, Carlos García Núñez, Three-dimensional graphene foam based triboelectric nanogenerators for energy systems and autonomous sensors, Nano Energy, Volume 112, 2023, 108475, ISSN 2211-2855.

Keywords: 3D graphene; Triboelectric nanogenerator; Energy harvesting; Self-powered sensors

Abstract

Optimisation of electrodeposition routes of birnessite manganese dioxide (MnO2) coatings onto 3D graphene foam substrates enabled greater attainable capacitances. Current pulse deposition method resulted in highest achievable areal capacitance of 530 mF/cm2 under a 10 mA/cm2 current rate, cycling performance with 91% retention after 9000 cycles, as well as improved rate capability when compared to the cyclic voltammetry or galvanostatic deposition. Introduction of oxygen functional groups to the graphene foam added initial pseudocapacitance and accelerated the rate for nucleation and growth of the MnO2 crystal grains, resulting in an areal capacitance of 410 mF/cm2 under a 10 mA/cm2 current rate. However, in this case the increase in specific capacitance was accompanied by sluggish kinetics for charge storage seen via impedance spectroscopy. The charge storage mechanism of the deposited MnO2 films was investigated using in situ Raman microscopy and analysis of peak shifts revealed expansion and contraction of birnessite MnO2, relating to exchange of Na+and H2O at the MnO2 interface.

Filipe Braga, Gabriel Casano, Luke M. Daniels, Marco Caffio, Laurence J. Hardwick, Electrodeposition of manganese dioxide coatings onto graphene foam substrates for electrochemical capacitors, Electrochimica Acta, Volume 455, 2023, 142433, ISSN 0013-4686, https://doi.org/10.1016/j.electacta.2023.142433.

Keywords: Birnessite MnO2; Pseudocapacitor; In situ Raman; Charge storage mechanism