Electrochemiluminescence sensing of vitamin B12 using laser-induced graphene based bipolar and single electrodes in a 3D-printed portable system

Vitamin B12 plays a very important role in human body and its deficiency can be detrimental to the production of red blood cells, anemia, memory loss, low immunity to infection, and permanent and severe damage in the nervous system and brain. In the present work, vitamin B12 sensing has been accomplished using two Electrochemiluminescence (ECL) platforms, one with Bipolar Electrode (BPE), while the second one Single Electrode (SE). The electrodes were fabricated on polyimide (PI) substrate by creating optimized Laser-Induced Graphene (LIG). With optimized speed and power of CO2 Laser, non-conducting portion of PI gets converted into conducting zone (electrodes) for ECL imaging. A 3D-printed miniaturized portable system was developed to detect and monitor the ECL signals. Android smartphone was effectively used to provide dual functions such as to drive the DC to DC buck-boost converter and to capture the ECL images. The sensing of vitamin B12 was accomplished in the linear range 0.5–700 nM and 0.5–1000 nM with a limit of detection (LOD) 0.107 nM (R2 = 0.98, n = 3) and 0.094 nM (R2 = 0.977, n = 3), respectively, for BPE and SE-based ECL platforms correspondingly. Therefore, proposed ECL platforms can be selectively used in various domains such as point of care testing (POCT) and biomedical applications.