An Introduction to mucus Rheology

Rheology, the study of the flow of matter, provides quantitative and objective viscoelasticity data. When applied to sputum, this measurement indicates its physical properties.

Abnormally viscous (G”) and elastic (G’) sputum makes expectoration difficult and obstructs the pulmonary tract.

The abnormal viscoelastic properties are connected to the overproduction of mucin-type glycoproteins and hypersecretion, which are typical of chronic inflammatory lung diseases.
Rheology of sputum makes it possible to distinguish between and even stratify different condition.

The sharp increase in the viscoelasticity of biological fluids is related to the phases of exacerbation that are characteristic of many respiratory diseases, such as Chronic Obstructive Pulmonary Disease (COPD) and cystic fibrosis. Rheology is therefore a relevant method to better understand, anticipate or treat these phases.

Rheology has also been used in a clinical setting to confirm the effect of mucolytics.

Since the Sixties, researchers have increasingly studied the viscoelastic properties of sputum, with the number of published articles increasing from 10 to 20 per year since 2012. The data measured are tangible and rigorous evidence of the mechanical properties related to the sputum structure.
Rubin’s sputum composition

Rheonova has created Rheomuco, an innovative high-precision device that is easy to use and designed to analyse sputum.

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Despite conclusive results (see our documentation centre), this biophysical method was kept confidential due to the complexity of conventional rheology. The primary reason stems from the use of current macro and micro rheometers.

Macro rheometers require large sample volumes but make it possible to work on heterogeneous samples and use a large number of measurement protocols. However these scientific machines must only be used by rheology specialists.

Micro rheometers are easier to use, with only one protocol, but heterogeneities affect the repeatability of measurements. In addition, often these are not standardized test benches.

Lastly, some studies have concluded that a dedicated device should be developed. These findings inspired Rheonova to create Rheomuco, an innovative high-precision device that is easy to use, designed to analyse sputum.