Novel 3D printed single electrode-based portable and miniaturized electrochemiluminescence platform to detect lactate from human serum

In low- and middle-income countries, three-dimensional printing (3DP) microfluidic devices have demonstrated their potential to be employed in a variety of point-of-care testing applications. This is due to the fact that they offer many advantages over traditional fabrication techniques, like rapid response, easy integration with miniaturized systems, requiring less sample volume, fast prototyping and cost-effectiveness. To the best of our knowledge for the first time, a novel 3D printed single electrode based electrochemiluminescence (3DP-SE-ECL) sensing device was fabricated and utilized to detect various analytes. To fabricate the 3DP-SE-ECL device, the commercially available conductive filaments, like graphene and carbon, were used and an in-depth analysis was performed by sensing H2O2. Furthermore, in order to validate the analytical performance, the best conductive material (graphene filament) was chosen to realize the optimized 3DP-SE-ECL platform, which was validated for lactate sensing. To detect the electrochemiluminescence signal, two approaches were used, first using photomultiplier tube (PMT) and the second by using a smartphone. The lactate concentration was changed from 100 to 7000 µM and a linear range was obtained from 100 to 1000 µM using both PMT and smartphone. Further, the limit of detection was measured to be 6.47 µM and 5.33 µM by smartphone and PMT respectively. To validate the practical usability of 3DP-SE-ECL, real sample analysis of lactate with standard spiking method was performed with excellent recovery rate. Overall, the fabricated 3D-SE-ECL device has the possibilities to be used for a variety of applications, including biomedical and environmental monitoring.