Monoclonal antibodies (mAbs) optical detection by coupling innovative imprinted biopolymers and magnetic beads: The case of therapeutic mAb anti-myostatin detection

Immunotherapy has revolutionized modern medicine, becoming the largest part of the growing bio-drugs market. Along with the progress in this direction, the need for reliable monoclonal antibodies (mAbs) monitoring methods is a current foremost issue. In this scenario, the goal of this study was to design a straightforward beads-based plasmonic approach that combines magnetic beads (MBs) with a polynorepinephrine imprinted biopolymer (IBP) for real-time mAbs detection in biological matrices. Specifically, MBs-encoded by a specific antigen were exploited not only for the selective capture of the target mAb from human serum, but also MBs are directly involved in the molecular architecture of a sandwich assay. The mAb extraction from the real matrix occurred in a site-oriented manner by exploiting a paratope-epitope specific recognition, while leaving the constant mAb fragment (Fc) free to interact with an IBP specific for the mAb Fc portion. Anti-MYO-029, a recombinant monoclonal IgG1 antibody developed for myostatin inhibition and muscular-wasting disorders' treatment in clinical settings, was addressed as biological target to evaluate the analytical performances of the beads-based sensing assay. Myostatin-neutralizing antibodies may be misused as performance-enhancing drugs in sports competitions and their effective quantification has a central role also in the anti-doping control field. The optimization of the assay conditions led to establishing an assay able to achieve very good analytical performances in terms of repeatability and sensitivity, with negligible cross-reactivity with other Ig classes and IgG subclasses. In this frame, we proposed an extremely modulable assay, with potential large applicability, for multiplexing mAbs detection.