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Updated: Jun 25, 2025

Three-Dimensionally Printed Microfluidic Cross-flow System for Ultrafiltration/Nanofiltration Membrane Performance Testing
Published on: February 13, 2016
Buffer effects on protein sieving losses in ultrafiltration and their relationship to biophysical properties
Aylin Mohammadzadehmarandi1, Andrew L Zydney1
1Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA.
Abstract:
The design of effective ultrafiltration/diafiltration processes for protein formulation requires the use of membranes with very high protein retention. The objective of this study was to examine the effects of specific buffers on the retention of a model protein (bovine serum albumin) during ultrafiltration. Albumin retention at pH 4.8 was significantly reduced in phosphate buffer compared with that in acetate, citrate, and histidine. This behavior was consistent with a small change in the effective albumin hydrodynamic diameter as determined by dynamic light scattering. The underlying conformational changes leading to this change in diameter were explored using circular dichroism spectroscopy and differential scanning calorimetry. These results provide important insights into the factors controlling protein retention during ultrafiltration and diafiltration.
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