Ion Selective Transport Across Liquid Membrane Mimicking Renal Tubule Function

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09450307
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 生物・生体工学
• Research Institution: Waseda University
• Principal Investigator: SAKAI Kiyotaka Waseda University, Science and Engineering, Professor, 理工学部, 教授 (00063727)
• Project Period (FY): 1997 – 1998
• Keywords: Artificial kidney / Dialysis / Urea / Ion / Electrodialysis / Extraction / Surfactant / Chelate

Research Abstract

Further improvement of hemodialysis treatments with artificial kidney requires the development of a new renal tubule system that removes only uremic toxins from the blood, or recovers essential ions and solutes from outfiowing diatysate and returns them to the blood.
The objective of the present study is to separate ions (Na^+, Cl^-) and urea and to recover the ions from the outfiowing dialysate. A potential difference was applied as a driving force using an ion selective liquid membrane to separate ions (Na^+, Cl^-) and urea and to concentrate the ions by dialysis. A PTFE membrane, impregnated with an organic solution in which reversed micelles were formed or chelate was dissolved was used as a liquid membrane. Using a reversed micelle liquid membrane, the transfer rate of Na^+ and Cl^- was higher than that of urea, and increased by applying the potential difference. Using a chelate liquid membrane, its membrane stability was higher than that of the reversed micelle liquid membrane. On the other hand, when no potential difference was applied, Na^+ and Cl^- permeated across the liquid membrane as fast as urea. Then a three chambers batch cell mimicking an electrodialysis apparatus was devised using the reversed micelle liquid membrane. When a potential difference was applied between outside two chambers as a driving force, Na^+ and Cl^- concentrations in the middle cell increased and urea concentration was kept to be constant. Therefore, repeated operation or continuous operation with the same cells connected makes it possible to separate ions (Na^+, Cl^-) and urea and concentrate ions (Na^+, Cl^-) efficiently.
In conclusion, separation of ions (Na^+, Cl^-) and urea and concentration of ions (Na^+, Cl^-) in NaCI and urea solution with the three chambers batch cell are feasible using the reversed micelle liquid membrane, and the function of the renal tubule can be modeled and essential ions and solutes can be recovered from outflowing dialysate and returned to the blood.