Innovative Microfluidic Dialyzer: Redefining Care for Patients on Dialysis

Background: Development of a miniature dialyzer can benefit patients with kidney failure, especially infants and patients that perform in-home low-flow-rate dialysis. Despite a few decades of research, an alternative to the existing bulky dialyzers has remained elusive. Here, a breakthrough microfluidic dialyzer with an order of magnitude smaller size and blood compartment volume compared to the existing dialyzers is presented. Methods: A miniature microfluidic dialyzer (MD) has been developed and its hydrodynamics and sieving characteristics have been analyzed through comprehensive numerical and experimental studies. An iterative design process has been pursued to minimize the dialyzer pressure drop well below that of the existing dialyzers such that it could also be operated with the arterial blood pressure. Measurements at different flow rates and urea removal under static and variable hemodynamic conditions have been performed, aimed at characterizing the device performance and control measures for reliable dialysis. Results: The new dialyzer has a blood compartment volume of 16.3 mL substantially smaller than ~100 mL blood volume of the current dialyzers. It operates on a reduced blood flow rate of 100 mL/min compared to the typical 300-500 mL/min practiced in conventional dialyzers as planned for eventually targeted patient groups. A dialyzer with a pressure drop of 6.2 ± 1.4 mmHg has been developed for a blood flow rate of 100 ml/min. This pressure drop is an order of magnitude less than that of a conventional dialyzer with a pressure drop of 31.1 ± 3.4 mmHg, tested under identical conditions. The urea sieving coefficient of the developed microfluidic dialyzer is 0.74, only marginally lower than that of a conventional dialyzer of 0.83 measured under identical conditions. The accompanying numerical models for pressure drop and urea removal predicted the outcomes of the tests. Conclusion: The innovative microfluidic dialyzer represents a significant advancement in dialysis technology, offering a smaller size, lower pressure drop, and comparable urea removal efficiency compared to conventional dialyzers. This breakthrough has the potential to greatly benefit patients with kidney failure, particularly infants and those requiring in-home low-flow-rate dialysis. Funding: NIDDK Support