BSA Retention in Single Channel Dialyzer

Regarding the single channel dialyzer chip with 20-nm thick nano-porous silicon membrane: 10 mm long, 300 µm deep, 500 µm wide channels.
Now that we’ve shown that a measurable quantity of urea is filtered out of DI water in one pass through the single channel dialyzer chip, we turn our attention to “Things Which Must Not Pass”. Albumin must be retained in the blood during HD so we will pump fluorescence tagged BSA through the single channel dialyzer chip at 5.6 µL/min and ensure that no measurable quantity is filtered through the membrane. To do this we have set up a dual path test. The first is the dialyzer submerged in a stirred beaker of DI water, just as used in the urea filter test. The other path pumps the BSA through tubing straight to a collection vessel. The length of the tubing is such that the volume is the same as the total volume in the dialyzer path. The idea is that there will be some loss of fluorescence due to photo bleaching and the control path will measure this. Both pumped and unpumped samples will be measured with the TECAN for fluorescence, excitation 495 nm, emission 535 nm. The graph below shows the results.

Figure 1: Graph of fluorescence results for Bovine Serum Albumen (tagged).


Conclusion: I hoped that the above graph will show that indeed, no albumin passes through the nanoporous membrane. But it doesn't really show much. The reasons are evident in the following picture. The BSA clumps will, in the future, be broken up using the sonicator. The DST will be utilized to verify the particle size after sonification.

Figure 2: Bovine Serum Albumen clumps and a broken honeycomb.

Future Tests Plans

Grafting PEG