|Beads/microspheres visualization and tracking in vitro [87,88,89], ex vivo [20, 90] and in vivo ||- Easily visualized.|
- Potential for in vivo tracking.
|- Most applicable in vitro and in small animal models ex vivo/in situ.|
- Data analysis can require careful application of modelled calculations that present opportunities for error.
- Some of the in vivo applications may require expensive visualization set up.
|Histology & Immunostaining (using specific antibodies, Lectins, PAS/AB) [90, 92, 93]||- Inexpensive, easily visualized.|
- Specific antibodies can provide precise mucin detection and localization or co-localization with other molecules.
- Fluorescent lectins can be used for semi-quantitation by fluorescence intensity measurement and are inexpensive
|- Applicable mostly in vitro and ex vivo.|
- When scoring systems are utilized, careful analysis by multiple individuals blinded to group treatments are necessary.
- Fixation and washing steps might result in mucus being washed away.
- Lectins bind to different carbohydrates in the oligosaccharide chains of glycoproteins and glycolipids and therefore are not mucin specific.
|Electron microscopy ||- In depth view of micro anatomical structures of cells and gel-forming mucins.||- Difficult to detect more than one type of gel mucin at the same time.|
- The type and duration of fixation is very important for retention of mucin structures.
|X-ray imaging analysis [1, 20, 95,96,97,98]||- Novel techniques provide in vivo ability to detect mucus|
- Very recent X-ray synchrotron  and quazi-monochromatic X-ray phase-contrast imaging techniques have been applied successfully to measure MCT in vivo, together with lung motion.
- Can detect mucus plugs in humans in vivo.
|- Expensive set-up and materials.|
- Potential for exposure to harmful rays.
- At the moment, are limited in utility for longitudinal in vivo studies.
- Highly specialized equipment and skills
|Volumetric – submucosal gland bubble visualization [55, 99]||- Detect ex vivo/in vitro increased output from single cell or multiple glands under normal or treatment conditions.|
- The total volume technique gives a simple quantitation of total mucus secretion ex vivo/in vitro for a constant time period at baseline and/or after treatment.
|- Volume output may not necessarily comprise only mucus but can also include changes in serous gland- and non-glandular cell-secretions.|
- Currently not applicable in vivo.