Water-based chitosan/reduced graphene oxide ink for extrusion printing of a disposable amperometric glucose sensor

Abstract

Recently, developing appropriate printing techniques and conductive inks has received considerable attention in the field of (bio)sensors. Extrusion printing technology is an interesting alternative to conventional screen-printing for making flexible and disposable electronics due to its special features such as, direct printing, easy control of design, and manufacturing processes. Moreover, fabricating highly dispersed and stable graphene inks with appropriate conductivity and printability is always a challenge in (bio)sensors. Here, a water-based chitosan/reduced graphene oxide (CS/rGO) ink was obtained using extrusion printing to make conductive electrodes on paper. CS/GO ratio of 0.2 showed the best stability, electrochemical performance and hydrophilicity (water contact angle of 85° ± 6). The resulting sensor was a simple two-electrode device based on the chronoamperometry technique, representing a good potential for detecting glucose in the linear range of 0.5 to 4 mM and with a limit of detection (LOD) of 0.45 mM (S/N = 3). Furthermore, this non-enzymatic sensor showed proper selectivity against interfering substances, as well as an excellent stability during 28 days (2.9% response fall). Ultimately, the developed conductive ink can be considered as an innovative material with high stability and dispersivity of rGO for the future studies on disposable (bio)sensors and flexible electronics.