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Air-sampled Filter Analysis for Endotoxins and DNA Content
Published on: March 7, 2016
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DNA RETENTION ON DEPTH FILTERS
Ohnmar Khanal1, Xuankuo Xu2, Nripen Singh2
1Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA.
Journal of Membrane Science
|June 22, 2019
Summary
Understanding how depth filters retain impurities like double-stranded DNA (dsDNA) is crucial for bioprocessing. This study reveals DNA retention mechanisms, showing smaller DNA fragments are retained more effectively within depth filter media.
Area of Science:
- Bioprocessing
- Filtration technology
- Molecular biology
Background:
- Depth filtration is vital for removing impurities during bioprocessing.
- Understanding impurity retention mechanisms in depth filters is complex due to filter composition.
- Double-stranded DNA (dsDNA) is a key impurity that needs efficient removal.
Purpose of the Study:
- To investigate the mechanisms of dsDNA retention within depth filter media.
- To elucidate the influence of DNA size and operational parameters on retention.
- To visualize DNA distribution within spent depth filter discs.
Main Methods:
- Confocal fluorescence microscopy was used to visualize fluorescently-labeled dsDNA distribution.
- Experiments varied DNA length, wash volume, and buffer ionic strength.
- Cellular DNA was labeled using 5-ethynyl-2'-deoxyuridine (EdU) in Chinese Hamster Ovary (CHO) cells.
Main Results:
- DNA displacement into the depth filter increased with decreasing DNA length.
- Increased wash volume and buffer ionic strength enhanced DNA displacement.
- CHO cellular DNA migrated deeper into the filter than pelletized DNA, highlighting size-dependent migration.
Conclusions:
- DNA size significantly impacts its migration and retention within depth filters.
- Operational parameters like wash volume and ionic strength modulate DNA retention.
- The study provides insights into nucleic acid and impurity removal in bioprocessing, with potential for small-scale studies.
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