Functionalized graphene foam as electrode for improved electrochemical storage

Non-covalent π-π functionalized Gii-senseⓇ graphene foam for interleukin 10 impedimetric detection

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. Biosensors based on graphene's conductivity and flexibility are attractive to offer simple single-use and reduced handling. However, oxidation of its carbon lattice to develop functional moieties for biomolecule immobilization cuts down its electronic conductivity potential. In this work, the authors present a microfluidic lab-on-chip device for simple impedimetric monitoring of IL-10 based on graphene foam (GF) flexible electrodes. Graphene's structure was maintained by employing π-π non-covalent functionalization with pyrene carboxylic acid (PCA). Impedimetric measurements could be performed in low ionic strength phosphate-buffered saline (LI-PBS). The PCA-antibody modification showed to endure the incubation, measurement, and washing processes performed in the microfluidic device. Electrode modification and measurements were characterized by, electrochemical impedance spectroscopy (EIS), contact angle, and scanning electron microscopy. From the contact angle results, we found that the wettability of the graphene surface increased gradually after each modification step. Detection measurements performed in the 3D-printed microfluidic device showed a linear response between 10 fg/mL to 100 fg/mL with a limit of detection (LOD) of 7.89 fg/mL in artificial saliva. With these features, the device was used to quantify IL-10 samples by the standard addition method for 10 fg and 50 fg with recoveries between 82% and 99%. Specificity was evaluated towards interleukin 6, TNF-⍺ and bovine serum albumin.

A high energy density asymmetric supercapacitor utilizing a nickel phosphate/graphene foam composite as the cathode and carbonized iron cations adsorbed onto polyaniline as the anode

This work presents the effect of different contents of graphene foam (GF) on the electrochemical capacitance of nickel phosphate Ni₃(PO₄)₂ nano-rods as an electrode material for hybrid electrochemical energy storage device applications.

Current and future directions in electron transfer chemistry of graphene

The participation of graphene in electron transfer chemistry, where an electron is transferred between graphene and other species, encompasses many important processes that have shown versatility and potential for use in important applications.