Screen-printed graphene-based electrochemical sensors for a microfluidic device

This work presents a new method for mass fabrication of a new microfluidic device with integrated graphene-based electrochemical electrodes by the screen printing technique for in-channel amperometric detection. Graphene-based working and counter electrodes were fabricated by screen printing graphene paste on a glass substrate, followed by screen printing of a silver/silver chloride (Ag/AgCl) reference electrode. The screen-printed substrate was then bonded to a prefabricated polydimethylsiloxane (PDMS) sheet containing microchannels via oxygen plasma treatment. The developed microfluidic device was then applied for glutathione analysis in pharmaceutical products. The method offers effective and fast glutathione detection with good analytical features including a wide dynamic range (10-500 mu M) and a low detection limit (3 mu M). In addition, the screen printed graphene electrode (SPGE) exhibits a good stability in a microfluidic flow system and good repeatability for amperometric detection. The method has numerous advantages including low fabrication cost, high sensitivity, high throughput and satisfactory reproducibility. Thus, it holds great promise for advanced analytical applications.