Extraction of Bionanomaterials from the Aqueous Bulk by Using Surface Active and Water-Soluble Magnetic Nanoparticles

Surface active and water-soluble magnetic nanoparticles (NPs) were used to demonstrate the extraction of bionanomaterials from the aqueous bulk. Au NPs conjugated with different water-insoluble and water-soluble proteins were used as model bionanomaterials. UV–visible studies, zeta potential, and microscopic analyses were performed to quantify the extraction. Sodium dodecyl sulfate and dimethylene bis­(dodecyldimethylammonium bromide) (12-2-12) stabilized surface active magnetic NPs were fully capable of extracting Au NPs conjugated with predominantly hydrophobic proteins from the aqueous bulk when placed at the aqueous–air interface. However, they were poor in extracting Au NPs from the aqueous bulk which were coated with predominantly hydrophilic water-soluble protein. On the other hand, water-soluble dodecyldimethyl-3-ammonio-1-propanesulfonate stabilized magnetic NPs proved to be fully capable of extracting all kinds of Au NPs conjugated with either water-soluble or water-insoluble proteins. The results highlight the remarkable ability of magnetic NPs in the extraction of bionanomaterials when placed at either biointerfaces or in the aqueous bulk of biological systems.