Physicochemical characterization and cytotoxicity assessment of sodium dodecyl sulfate (SDS) modified chitosan (SDSCS) before and after removal of aflatoxins (AFs) as a potential mycotoxin Binder

Aflatoxins in food and feed with prominent toxic effects have jeopardized public health for decades. This investigation intends to explore synthesized SDS-modified chitosan as new generation of binder for removal of aflatoxin using a straightforward ionic cross-linking approach. The primary objective of this technique was to enhance affinity and adsorption capability of SDSCS towards aflatoxins. In this context, physicochemical properties of SDSCS characterized with advanced analytical techniques such as scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FT-IR) before and after removal of aflatoxin. In this study, effect of the pH on the adsorption of aflatoxins (6ppb) indicated that the increase in SDSCS concentration from low (0.5) to high (2 %) resulted in an increase of about 80 %, 78 % and 81 % in the adsorption percentage of AFB₁, AFG₁, and AFB₂ & AFG₂, respectively. FT-IR analysis showed the intramolecular interactions of the amine groups of chitosan and sulfate group of SDS formed a stable complex in the removal of aflatoxin that verified with appearance of three new additional peaks at 1323.50, 984.34 and 603.42 cm^-1. Notably, SEM images revealed that the porous SDSCS network was filled with aflatoxin molecules supported with EDS findings. Also, in vitro cytotoxicity assessments demonstrated that SDSCS protected HepG₂ cells against cytotoxic effect caused by aflatoxin (5 µM) in a concentration-dependent manner compared to the control (p<0.01). Collectively, the adsorption mechanism may involve attraction of anionic aflatoxin molecule into the interconnected pores of SDSCS complex with numerous cationic active site via hydrogen bond and van der waals force.