Development of a specific magnetic support for tetanus toxoid separation 

Magnetic separation is currently gaining significant attention as a process in the biotechnology industry. The innovative solutions offered by this methodology for separating analytes of interest have advanced beyond the analytical scale. The complexity of this technique lies in developing an optimal separation support for the system in question. Considering that tetanus toxoid is part of a wide range of products in the pharmaceutical industry, such as conjugate vaccines based on tetanus toxoid as a carrier protein, the development of selective magnetic separation techniques for tetanus toxoid represents a novel alternative. For this reason, in this work, a magnetic support was developed based on anti-tetanus toxoid antibody immobilized on iron oxide nanoparticles. The nanoparticles were obtained by coprecipitation and post-synthesis modification with polyacrylic acid and gallic acid. The antibody immobilization was carried out through interaction with protein G, which was previously anchored to the nanoparticles. The nanoparticles were characterized by X-ray Diffraction, Infrared Spectroscopy, Transmission Electron Microscopy, Scanning Electron Microscopy, Thermogravimetry, Vibrating Sample Magnetometry, Dynamic Light Scattering, and Zeta Potential. The obtained nanoparticles showed a diffraction pattern corresponding to magnetite, a morphology of aggregated spheres with a particle size of 13 nm, and stability in aqueous suspension. The covalent anchoring of protein G was evaluated through colorimetry and SDS-PAGE Electrophoresis. The functionalized nanoparticles with protein G were able to immobilize tetanus toxoid antibody through interaction in an aqueous medium.