Numerical investigation of selective withdrawal in a pancreatic cell islet encapsulation apparatus

Abstract

The development of an efficient microencapsulation apparatus is a major challenge for islet transplantation. To that end, the flow generated by selective withdrawal in an apparatus for micro-encapsulation of pancreatic islets is studied through CFD simulations. Each islet enters individually a chamber containing a twolayer system in which is encapsulated by selective withdrawal. Optimal encapsulation occurs, when the perturbed interface is kept stable and transition to viscous entrainment is prevented. Simulations were validated with experimental data. Contrary to previous studies that simplify the problem by approximating the tubes as a doublet of a point mass source and sink, the model presented here employs a detailed geometry. Numerical results shed light on the dependence of the shape of the interface on flow, geometry and physical parameters. These observations can contribute to the design of encapsulation apparatuses considering polydispersity in size and the different shape of the islets.