A Reusable Magnetic Probe Based on Staphylococcus aureus Peptidoglycan for Efficient Tetrodotoxin Removal

The residual tetrodotoxin (TTX) in discarded pufferfish viscera poses environmental and safety risks. However, current TTX removal technologies suffer from low efficiency, long processing time, and difficulty in separating adsorbents from toxins. To address this, we developed an efficient and convenient removal method by constructing an Staphylococcus aureus peptidoglycan-labeled magnetic bead probe (S-PG-MB) from Staphylococcus aureus peptidoglycan (S-PG) and carboxylated magnetic beads (MB). Using 1.0 μm MB at an MB-to-S-PG ratio of 1:2, activation with 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide (EDC) (20 mg/mL) for 45 min, and coupling in pH 6.5 sodium acetate buffer for 105 min, the resulting probe achieved up to 95% TTX removal at 37°C within 35 min—more than twice the efficiency of S-PG alone. Toxicity evaluation using SH-SY5Y neuronal cells and a mouse bioassay further confirmed that the S-PG-MB probe reduced TTX neurotoxicity by approximately 97%. It also effectively removed TTX from the internal organs of perch, with a removal rate of 73%, and maintained stable performance over five reuse cycles (< 4% efficiency loss). Kinetic and isotherm modeling indicated monolayer adsorption that was largely temperature-independent. The high performance was attributed to the uniform distribution on the probe surface, enabling rapid chemisorption. In summary, the S-PG-MB probe combines operational simplicity, high capacity, and reusability, offering a promising idea and approach for developing novel adsorbents and advancing efficient removal technologies for TTX and other marine biotoxins.