Multiphase modelling of an experimental device for conformal coating of pancreatic islets

This paper illustrates the development of an SPH model for the analysis of a relatively complex multiphase flow occurring in an experimental microfluidic device for encapsulation of islets of Langerhans (i.e. pancreatic cells aggregates) through a bio-compatible and permeable polymeric coating. Cell encapsulation guarantees optimal immunoisolation while allowing glucose and insulin diffusion, thus enhancing the possibility of transplantation without immunosuppression in Type-1 diabetic patients to restore correct glucose metabolism. A WCSPH numerical modelling, based on the formulation by Adami et al. (2010), of the multiphase flow in the experimental device proved to be phase conservative with respect to finite volume / finite element models early setups, and is able to accurately mimic the encapsulation process. The SPH model allows evaluating: (i) the feasibility of reproducing the physical phenomenon leading to islet encapsulation, such as surface tension at the interface and physical viscosity of both fluids (as shown experimentally by Suryo & Basaran, 2006); (ii) the influence of modulating different process parameters on the fluid dynamics and coating characteristics; and (iii) to overcome the limits of the early numerical model while increasing the resolution. The model represents a valuable, time-and cost-effective tool for further refinement of the experimental process.