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Nylon-Based Affinity Membranes: Impacts of Surface Modification on Protein Adsorption
1Biochemical Engineering Division, GBF, Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, Mascheroder Weg 1, D-38124, Germany
Journal of Colloid and Interface Science
|October 30, 1998
Summary
Formaldehyde activation of nylon membranes with dextran offers a cost-effective method for reducing protein adsorption. This technique yields high dextran density and stable coatings, outperforming bisoxirane activation for membrane applications.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Surface Chemistry
Background:
- Nylon microfiltration membranes are susceptible to protein adsorption, limiting their use in biomedical applications.
- Surface modification is crucial to reduce nonspecific protein binding and enhance membrane performance.
- Dextran coatings are explored for their biocompatibility and ability to create antifouling surfaces.
Purpose of the Study:
- To compare the efficacy of bisoxirane and formaldehyde activation methods for immobilizing dextran onto nylon membranes.
- To evaluate the resulting dextran-coated membranes for hemoglobin adsorption and stability.
- To investigate the potential of these modified membranes for biomolecule immobilization and affinity chromatography.
Main Methods:
- Nylon membranes were activated using bisoxirane and formaldehyde to functionalize terminal amino and amide groups.
- Dextran polymers of varying molecular weights were covalently immobilized onto the activated membranes.
- Hemoglobin adsorption, coating stability across pH ranges, and ligand immobilization capacities were assessed.
Main Results:
- Both activation methods reduced hemoglobin adsorption, with formaldehyde activation being simpler, cheaper, and yielding higher dextran density.
- Formaldehyde activation required lower molecular weight dextran (6000 Da) compared to bisoxirane activation (>40,000 Da).
- Dextran coatings enabled high immobilization of Cibacron Blue F3G-A and iminodiacetic acid, leading to significant protein binding capacities.
Conclusions:
- Formaldehyde activation is a superior method for creating dextran-coated nylon membranes due to its cost-effectiveness, efficiency, and high performance.
- The dextran coating structure influences hydraulic permeability and facilitates high ligand loading for affinity applications.
- Dextran-modified membranes demonstrate potential for use in affinity chromatography with substantial binding capacities for proteins like lysozyme and concanavalin A.