Design and development of an apparatus for microencapsulation of pancreatic cell islets

Abstract

Transplantation of encapsulated islets of Langerhans is a therapeutic modality for treatment of Type 1 diabetes mellitus. Conventional microencapsulation technologies fail to prevail, as they produce single-sized microcapsules and attain low efficiencies. Given the fact of polydispersity in islets, a different manipulation is required in every occasion, in order to fabricate microcapsules of proper size efficiently. Efficiency here is defined as the ratio of the number of properly encapsulated islets to the total number of islets fed. By proper encapsulation it is meant one in which the encapsulated islets are viable and functional. In this Dissertation, we propose a novel isleτ microencapsulation apparatus designed by the principles of Mechanics and Cytotechnology. The fundamental idea of our approach is that encapsulation is driven by islet motion and capsule size and shape are determined by the individual islet size and shape, respectively. We focus on two requirements; the accurate separation of loaded islets to encapsulate one islet per capsule and the uniform thickness of the capsule membrane to accommodate the heterogeneous morphology of islets. The first requirement is met by the utilization of hydrodynamic focusing as a feeding system in our device. The second requirement is met by the employment of selective withdrawal as an encapsulation method.