Pyrene-Appended Boronic Acids on Graphene Foam Electrodes Provide Quantum Capacitance-Based Molecular Sensors for Lactate.

Molecular recognition and sensing can be coupled to interfacial capacitance changes on graphene foam surfaces linked to double layer effects and coupled to enhanced quantum capacitance. 3D graphene foam film electrodes (Gii-Sens; thickness approximately 40 μm; roughness factor approximately 100) immersed in aqueous buffer media exhibit an order of magnitude jump in electrochemical capacitance upon adsorption of a charged molecular receptor based on pyrene-appended boronic acids (here, 4-borono-1-(pyren-2-ylmethyl)pyridin-1-ium bromide, or abbreviated T1). This pyrene-appended pyridinium boronic acid receptor is employed here as a molecular receptor for lactate.

Polymer indicator displacement assay: electrochemical glucose monitoring based on boronic acid receptors and graphene foam competitively binding with poly-nordihydroguaiaretic acid.

The concept of a reversible polymer displacement sensor mechanism for electrochemical glucose monitoring is demonstrated. A pyrene-derivatised boronic acid chemo-receptor for glucose is adsorbed onto a graphene foam electrode. Spontaneous oxidative polymerisation of nordihydroguaiaretic acid (NHG) onto the graphene foam electrode leads to a redox active film (poly-NHG) covalently attached to the boronic acid receptors.