Bile acid transporter mediated endocytosis of oral bile acid conjugated nanocomplex.

The development of highly funtional and orally available nanoparticles is the ultimate goal in nanoparticle delivery. Various functional nanoparticles have been studied to that end but there has yet to be an oral nanoparticle that can be successfully applied. Here, we describe for the first time a novel bile acid conjugated nanoparticle that can be selectively absorbed by bile acid transporters in the small intestine. The bile acid conjugate nanoparticles that were first treated with enterocytes were successfully attached to the cell surface and then internalized inside the cells. We show that bile acid based interaction between a nanoparticle and its transporter induces its endocytosis and cellular uptake. This feature of cellular activity, described here for the first time, could be well utilized in the uptake of nanoparticles or macromolecules inside epithelial cells for oral delivery. In animal studies, bile acid conjugated self-assembling nanocomplexes successfully interacted with bile acid transporters in the ileum and were subsequently taken up into the epithelial cells. Considering the importance of orally deliverable nanoparticles, this nanotechnology using bile acid conjugation and transporter mediated endocytosis could be a crucial method for the successful application of various nanoparticles.