The insulin-dependent (type I) diabetic population is increasing worldwide at an alarming rate, with no permanent cure foreseen in the near future. A promising alternative to insulin injection therapy is the intravascular hybrid artificial pancreas (HAP), which consists of an inert cylindrical housing enclosing a single, tubular semipermeable hollow fiber membrane epoxied at the ends. Donor islets of Langerhans can be seeded in the annular space, and are thus protected from the recipient's immune system HAP-type devices were proposed in the early 1970s, but have not reached the clinical stage due to lack of scale-up criteria The goal of this project was to establish design criteria for HAPs based on classical chemical engineering principles which would allow their use in human diabetics One approach involved the in vitro perfusion of HAPs in which the annular compartment was initially filled with a glucose solution of known concentration. A washout experiment was then conducted by perfusing the HAP with solute-free buffer The glucose washout time was found to depend on flow rate, device dimensions, membrane fouling with bovine serum albumin, and the presence of glass beads in the annular space representing islets HAP performance was also analyzed using a theoretical transport model which accounts for both solute convection and diffusion in all three regions of the HAP (lumen, membrane, and annular space). The model was found to be in very good agreement with the glucose washout data Our results show that mass transfer in the HAP is very complex; but that through the rational design of experiments and mathematical simulations one can obtain new insights into the solute transport behavior ultimately leading to devices suitable for human use.
|Published - Dec 1 1997
All Science Journal Classification (ASJC) codes
- Molecular Biology