FAQ Rheomuco

Rheology

What is Rheomuco?

Rheomuco is a rheometer designed to measure the viscoelastic properties of mucus.

What is the rheology?

Rheology is the study of deformation and flow of materials. Rheology is concerned with the question ‘what make a material flow or not under a force?’

What is mucus rheology?

The mucus is an integrated structure of biopolymers. Its physical behaviour is complex with highly variable visco-elastic properties that are between those of a viscous liquid and an elastic solid. Rheological measurements, including viscosity (resistance under flow) and elasticity (stiffness), are often used together to describe the consistency of mucus.

Why is mucus rheology relevant to respiratory diseases?

The major function of mucus is to protect the lung epithelium against foreign particles and chemicals entering the lung. The mucus is comprised of water, ions, and various kinds of macromolecules some of which possess the protective functions such as anti-microbial, anti-protease, and anti-oxidant activity. Mucus glycoproteins or mucins are mainly responsible for the viscoelastic property of mucus, which is crucial for the effective mucociliary clearance.

During bronchial infection for example in cystic fibrosis, the loss of water and the increase in macromolecules result in a marked increase in viscosity and adhesiveness responsible for the mucus transport impairment.

Therefore, the respiratory mucus needs appropriate physicochemical properties for the protection, hydration and lubrication of the underlying airway epithelium.

What type of respiratory diseases are concerned?

Lung diseases with abnormal mucus formation, commonly called muco-obstructive diseases such as COPD, cystic fibrosis, primary ciliary dyskinesia, and non-cystic fibrosis bronchiectasis.

What type of tests do you use to analyse the viscoelastic properties of the mucus?

We use a strain sweep test which is powerful tool to characterize structured fluids such as mucus. During the measurement the strain amplitude is progressively increased with a fixed frequency at 1Hz.

This test will not only give us the information needed about the storage modulus or elastic modulus (G’) and the loss modulus or viscous modulus (G”) but also the yield and flow points.

What are the output results of Rheomuco and what do they mean?

The results displayed by Rheomuco are:

Viscoelastic modulus (G*): Stiffness of the mucus at rest, related to constituents’ concentration in mucus
Damping factor (tan (δ)): Ratio of viscous effects on elastic effects, related to molecular nature of the constituents in mucus
Critical strain (γc): Stringiness, stretchability of the mucus before flow
Critical stress (σc): Gel force, strength of the mucus before flow

Can I do other tests than a strain sweep?

Yes, if you wish to use Rheomuco for research capacity, we do have Rheomuco research that allows you to choose between 3 predefined tests, strain sweep, frequency sweep and Flow and optain additional rheological properties. If you have advanced knowledge I rheology, you can choose to design your own test.

Can Rheonova help me understand the results?

Rheonova can assist you with your project and provide a complete analysis of your results. We also can provide you and your team with mucus rheology courses.

Sample

What type of bronchial mucus can I analyse?

Sputum from patient
Mucus extracted from animal testing
Mucus recovered from ALI (Air Liquid Interface) cell culture

What are the volume needed?

For ALI mucus: 20µL
For sputum and mucus: 150 µL to 680 µL

Does the mucus sample need to be fresh it can it be stored? If yes how?

The mucus can be tested fresh and stored in ice or 4°c up to 4 hours after extraction. But it can also be stored at – 20°C for short storage (1 or 2 months) and at -80°C for longer storage (more than 2 months)

At what temperature do you analyse the mucus?

We recommend to perform the analysis at 37°C (Rheomuco default setting, but temperature control can be enabled)

How do you handle sample evaporation?

The test time is quite fast 5 minutes and the sample does not have the time to evaporate. However, we do sell anti-evaporation trap

How do you prevent contamination?

During the analysis, there is protective glass that will limit projections.

After analysis, we recommend cleaning the surfaces and the geometries with anti-bacterial detergents

Can I analyse the same sample twice? Can I use the analysed to sample to do bacteriology testing?

No, the same sample cannot be analysed twice because the structure of the mucus is impacted by the analysis.
No, you cannot use the same sample for bacterial testing because the geometries are not sterile.

Device

Does it need any consumables?

No, we use reusable geometries

How long does geometries last?

Up to 500 uses if properly handled and stored

Does it need a computer to function?

Yes, Rheomuco works only through a computer with our applications.

The computer needs these minimum requirements for it to work:

Windows 10, 64 bits, with administrator rights
Processor: Intel Core i3
RAM: 4 Gb minimum
Hard drive: 500 Gb minimum
Minimum screen resolution: width 1280, height 768

Does it have a touch screen?

How long are the measurement?

For a strain sweep test, the measurement takes only 4 minutes

Where can I set up Rheomuco?

We recommend setting up Rheomuco on a Laboratory bench or table anchored in the ground with minimum vibration level. We do not recommend setting it up next to -80°C freezer or centrifuge.

During the analysis, do not use the centrifuge, do not slam doors or dance next the device. 😊

How do you handle the maintenance of Rheomuco?

After purchase, Rheomuco is warranted for the first year.

You can contact our services sup port@rheomuco.fr, describing the problem thoroughly and we will get back to you with a solution in the next 48 hours (during working days).

After the first year, Rheonova offers 3 types of maintenance contract

Please contact us at contact@rheomuco.fr if you wish to subscribe to a maintenance contract.