Nanobody immobilization on magnetic nanoparticles via monomeric streptavidin-biotin specific interaction for aflatoxin adsorption

A new magnetic aflatoxin (AF) adsorbent was synthesized by nanobody (Nb28) immobilization on magnetic nanoparticles (MNPs). Monomeric streptavidin (mSA)-biotin specific interaction technology was used as a linker for nanobody immobilization. As a magnetic solid support, Fe₃O₄ nanoparticles were modified with tetraethyl orthosilicate (TEOS), (3-Aminopropyl) trimethoxysilane (APTMS), and glutaraldehyde (GA). According to the characterization results, modified MNPs were monodisperse, paramagnetic, with average diameter of 450 nm and they showed less susceptibility to oxidation on air. MNPs-Nb28 and MNPs-mSA-Nb28 enzymatic activity was analyzed by high-performance liquid chromatography (HPLC) and showed the highest level of adsorption under optimal conditions for aflatoxin G₂ (AFG₂), reaching concentration reduction up to 96.9% and 97.1%, respectively. MNPs-Nb28 showed higher stability over storage time, temperature, and pH compare to MNPs-mSA-Nb28. The maximum AF adsorption capacities of MNPs-Nb28 and MNPs-mSA-Nb28 were 193 µg·g⁻¹ and 194 µg·g⁻¹, respectively. Both nanocomposites were proven to be a reliable tool for fast and efficient removal of different aflatoxins (AFs) from solution.