Regenerative Core–Shell Nanoparticles for Simultaneous Removal and Detection of Endotoxins

Detection and removal of lipopolysaccharides (LPS) from food and pharmaceutical preparations is important for their safe intake and administration to avoid septic shock. We have developed an abiotic system for reversible capture, removal, and detection of LPS in aqueous solutions. Our system comprises long C18 acyl chains tethered to Fe3O4/Au/Fe3O4 nanoflowers (NFs) that act as solid supports during the separation process. The reversible LPS binding is mediated by facile hydrophobic interactions between the C18 chains and the bioactive lipid A component present on the LPS molecule. Various parameters such as pH, solvent, sonication time, NF concentration, alkane chain length, and density are optimized to achieve a maximum LPS capture efficiency. The NFs can be reused at least three times by simply breaking the NF-LPS complexes in the presence of food-grade surfactants, making the entire process safe, efficient, and scalable. The regenerated particles also serve as colorimetric labels in dot blot bioassays for simple and rapid estimation of the LPS removed.