A Green and Facile Approach of Graphite Conductive Ink Preparation for Electrochemical Sensing Application

Conventionally, Graphite (GR) conductive ink is formulated by dispersing GR particles in organic solvents like N-methyl-2-Pyrrolidone(NMP), Dimethylformamide(DMF), etc.; however, these solvents are toxic and require high annealing temperatures, render them incompatible for flexible substrate. Here, we report a green and facile method to synthesize GR conductive ink by employing the eco-friendly solvent ethanol and acetone with biodegradable binder Cellulose Acetate (CA) and its subsequent use in fabricating disposable paper sensors. Characterization of paper sensors revealed uniform morphology with good conductivity. The choice of CA to GR ratio and paper grade improved the sensor's electrochemical performance. Finally, we evaluated the utility of the fabricated paper sensor in estimating bovine serum albumin (BSA) by employing the redox cycling process. Chronoamperiometry detection of BSA showed a linear range between 0-500mg/dl with a detection limit of 1.48mg/dl. This work provides a promising way to formulate a sustainable, affordable, and easily scalable method for GR conductive ink preparation for flexible electrochemical sensing applications.