Biocompatible magnetic nanoparticles for protein cellular targeting

Various inorganic biocompatible nanoparticles (NPs) are considered suitable carriers for targeted cellular delivery of various drugs, proteins, and peptides through the cell membrane into cells. Stable NP conjugates may also be used to verify the uptake specificity and to monitor the post-uptake fate of the conjugated species. In this frame, covalent conjugates between carboxymethyl-dextran-coated magnetic NPs and bovine betalactoglobulin (BLG, a common food allergen) were prepared to address the issue of allergen recognition and uptake. NP biocompatibility was confirmed on various model cell systems. Then, human monocytes were incubated with different kinds of NPs, and subsequently separated by a magnetic system. BLG-functionalized NPs were taken up in larger amounts and more rapidly than unmodified NPs. Binding of fluorescent probes either to the NPs or to the NP-BLG conjugates allowed studies on their intracellular localization by confocal microscopy. These studies indicate that conjugates of common food allergens with magnetic NPs may be used to monitor the intracellular (and, ultimately, the intratissutal) path followed by food allergens when taken up by humans.