


Like Mother’s Milk?


"The key challenge is how to make a nanoparticle get through this barrier of cells,” Omid Farokhzad, director of the Laboratory of Nanomedicine and Biomaterials at BWH, stated in the press release. He explained how the lining is “analogous to a brick wall where the bricks are the cells and the mortar is the attachments, and nothing can penetrate that wall.” To break through the barrier, he and his colleagues based their work on previous research that explained how babies are able to absorb antibodies from their mothers' milk in order to enhance their own immune defenses. Essentially, antibodies within maternal milk attach to a cell surface receptor called the FcRN, and this grants them passport through a baby's intestinal lining into adjacent blood vessels. Mimicking this mechanism, the researchers coated nanoparticles with Fc proteins — the part of the antibody that binds to the FcRN receptor. After ingestion, the protein would bind to the FcRN in the intestinal lining and gain entry, bringing the entire nanoparticle with them.

For this study, the researchers demonstrated how nanoparticle pills could deliver insulin to mice. After coating the pills with Fc proteins, the team discovered that the insulin they contained reached the bloodstream 11 times more efficiently than nanoparticle pills without the coating. Most importantly, the amount of insulin delivered was large enough to lower the mice's blood sugar levels. The team is now hoping to design nanoparticles that are able to cross other barriers, such as the blood-brain barrier, which prevents many drugs from reaching the brain. "If you can penetrate the mucosa in the intestine, maybe next you can penetrate the mucosa in the lungs, maybe the blood-brain barrier, maybe the placental barrier," Farokhzad said.

Source: Pridgen E, Farokhzad O, Langer R, et al. Transepithelial Transport of Fc-Targeted Nanoparticles by the Neonatal Fc Receptor for Oral Delivery. Science Translational Medicine. 2013.