An Organoid-derived Cell Layer as an in vitro Model for US-mediated Drug Delivery Studies

Standard in vitro models to study intestinal drug absorption and delivery, including ultrasound (US)-mediated drug delivery, are grown from tumorous colon and rectum cells. However, the intestinal epithelium is a heterogeneous tissue and includes stem cells that differentiate into multiple cell types, including those responsible for absorption of nutrients, secretion of mucus, sensing of nutrients and immunity. Conventional cell monolayers lack this complexity. Organoid (OG)-derived cell layers may be more physiologically relevant. This paper presents a method for growing a confluent cell layer from rectal OGs on inserts and describes how this layer was used to compare the effects of US in combination with microbubbles (MBs) and US plus nanodroplets (NDs) on the intestinal barrier function and the permeation of insulin across the cell layer. Both treatments decreased the barrier function of the cell layer to about half their original values. US with MBs created a pore in the tissue and resulted in a 13-fold increase in insulin permeation compared to US with NDs.