Figure 3.

Photos of an electrochemical immunosensor developed for detecting an MS-associated protein biomarker, i.e., CCL5 chemokine. The sensor was based on biotinylated capture anti-CCL5 antibodies immobilized on magnetic beads (MBs) pre-coated with neutravidin (Neu), which could form sandwich-type immunocomplexes with the CCL5 analyte, detection anti-CCL5 antibodies and, finally, horseradish peroxidase-labeled secondary antibodies; the electrochemical signal is generated in the presence of the H₂O₂/hydroquinone system. (1). SPCE: Screen-printed carbon electrode. (2). Magnet casing prepared in-house from polymethylmethacrylate (PMMA) with an encapsulated magnet. (3). Addition of the suspension of MBs-Neu-immunocomplexes onto the SPCE-sensing surface. (4). SPCE with the MBs-Neu-immunocomplexes immersed into a 10 mL electrochemical cell to measure the electrochemical signal. (Reproduced from [78]).