A functionalization study of aerosol jet printed organic electrochemical transistors (OECTs) for glucose detection

In this work, we have conducted a functionalization study of organic electrochemical transistors (OECTs) for glucose detection. The functionalization method of a biosensing device strongly affects its sensitivity and range of detection. Here, a glucose sensing study was performed on aerosol jet (AJ) printed OECTs via four different functionalization configurations: unfunctionalized device with floating GOx, PEDOT:PSS channel functionalized with GOx, printed Pt gate functionalized with GOx, and sputtered Pt gate functionalized with GOx, in order to study the effect of the functionalization site and the utilized nanomaterials on the sensing range and sensitivity. We found that the printed OECT with the GOx functionalized printed Pt gate exhibits the best performance. It demonstrates a large glucose (in PBS solution) detection range between 100 nM and 50 mM with two sensitivities of 0.022 NR per dec for 100 nM to 250 μM and 0.255 NR per dec for 250 μM to 50 mM. The OECT with the functionalized printed Pt gate was then evaluated for the detection of glucose in an artificial sweat buffer, demonstrating a detection range of 0.1 to 10 mM with two linear slopes of 0.068 NR per dec for 100 nM–500 μM and 0.384 NR per dec for 500 μM–10 mM. Also, AJ printing and laser sintering offer the benefit of simultaneous deposition and patterning of materials and rapid annealing of materials, and hence, they simplify the fabrication process and reduce the fabrication cost. These results confirm that these functionalized printed OECT based sensors are highly promising for application as non-invasive electrochemical glucose sensors. Thus, clearly for biosensor development, the choice of the functionalization site and material is very important.