Effect of agitation in magneto-assay performance

Here, we optimized a classical ELISA for detection of myeloperoxidase (MPO) that took 3 h and generated a limit of detection (LOD) of 4.87 ng mL−1. This assay was then formatted into a 30-min magneto-immunoassay that had an LOD of 1.65 ng mL−1. MPO magneto-immunodetection was next performed under different agitation conditions. The results showed that sample volume had a high effect in the incubations performed under rotation, with signals 50% higher in 0.5-1 mL than in 100 μL samples. On the contrary, vortex agitation generated similar signals for the different volumes tested (100 μL, 500 μL and 1 mL), which entailed a 50% enhancement in target recovery in 100 μL samples compared to rotation. This demonstrated that sample volume had different effect in magneto-immunobinding efficiency under different agitation conditions and suggested that magneto-assay automation could benefit from combinations of agitation types, selected in accordance to analyte type and sample volume.