Drying techniques for the visualisation of agarose-based chromatography media by scanning electron microscopy

Area of Science:

• Materials Science
• Biotechnology
• Microscopy

Background:

• Drying chromatography resins is crucial for Scanning Electron Microscopy (SEM) imaging.
• Agarose-based resins require careful drying to prevent artefacts and preserve ultrastructure.

Purpose of the Study:

• To compare critical point drying and freeze drying techniques for agarose-based chromatography resins.
• To evaluate the impact of drying methods on resin morphology and ultrastructure for SEM analysis.

Main Methods:

• Critical point drying and freeze drying protocols were applied to MabSelect™ and Capto™ Adhere resins.
• Morphological analysis of dried resins was performed using Scanning Electron Microscopy (SEM).

Main Results:

• Critical point drying yielded superior results, enabling clear visualization of polymer fibers (≈20 nm) and pore sizes (≈100 nm).
• Freeze drying induced significant bead damage, including fragmentation in MabSelect™ and partial disintegration in Capto™ Adhere resins.
• The extent of damage correlated with the agarose crosslinking and strength of the resins.

Conclusions:

• Critical point drying is the preferred method for high-resolution SEM imaging of agarose chromatography resins.
• Freeze drying, while causing damage, may offer insights into the mechanical properties of these resins.
• Understanding drying effects is vital for accurate structural characterization of chromatography media.