01
Aggregation and disaggregation kinetics
Measurement of how red blood cell clusters form and rupture as a function of shear rate, interaction strength, haematocrit and cell mechanical properties.
ESA Human and Robotic Exploration
KRABS Kinetics of Red Cell Aggregation and Blood Structure–Rheology Link
An interdisciplinary microgravity experiment investigating how red blood cell aggregation influences blood structure, viscosity and the risk of coagulation during spaceflight.
Status
Selected
ESA reference
I-2022-00061
Experimental platform
Sounding rocket
Discipline
Life Sciences
Project overview
Understanding blood aggregation in microgravity
KRABS investigates how red blood cell aggregates form,
evolve and disintegrate under flow when sedimentation is
suppressed.
Blood plasma proteins promote the reversible aggregation of red blood cells. These aggregates increase blood viscosity, particularly in stagnant regions or under low-shear conditions.
In microgravity, reduced flow velocities and haematological changes may reinforce aggregation, increase local blood viscosity and contribute to conditions favourable to coagulation and thrombus formation.
KRABS will use extended periods of microgravity aboard a sounding rocket to characterise the morphology, size distribution and dynamic evolution of red blood cell aggregates under controlled shear flow.
Scientific approach
Three connected levels of investigation
The project connects microscopic aggregate dynamics with macroscopic blood rheology and potential countermeasures against coagulation.
02
Blood structure and rheology
Characterisation of aggregate morphology, gel-like networks, fractal structure, viscosity and yield stress under conditions where sedimentation is suppressed.
03
Nanomaterial countermeasures
Investigation of nanoparticles and two-dimensional nanomaterials, including MXenes, for their potential to modulate coagulation and reduce thrombotic risk.
Experimental concept
From controlled blood samples to quantitative microgravity data
The experiment combines controlled sample preparation, low-shear flow and advanced optical diagnostics during an extended microgravity phase.
Sample preparation
Red blood cell suspensions are prepared with selected concentrations of fibrinogen, dextran or anticoagulant nanomaterials and maintained under continuous stirring before injection.
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Microgravity flow experiment
Samples are injected into a controlled flow chamber and subjected to low or moderate shear for approximately 20–120 seconds while aggregation and disaggregation occur.
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Integrated analysis
Optical, rheological and biochemical measurements are combined to establish links between blood microstructure, viscosity, aggregation kinetics and coagulation behaviour.
Project objectives
Linking cell-scale interactions to cardiovascular risk
Measure the time evolution and steady-state size distribution of red blood cell aggregates under shear.
Develop kinetic equations describing aggregation and disaggregation rates in flowing blood.
Characterise gel-like aggregate networks, connectivity and fractal structure at very low shear rates.
Establish the relationship between blood microstructure, viscosity and yield stress.
Assess the influence of haematocrit, aggregation strength and red blood cell deformability.
Evaluate selected nanomaterials as potential countermeasures against enhanced coagulation.
Experimental systems
Integrated optical, fluidic and rheological instrumentation
The experimental module is designed to provide complementary measurements of red blood cell structure, dynamics and rheological behaviour.
Flow chamber
A compact chamber approximately 100–200 µm thick, designed to support controlled shear flow and the formation of extended red blood cell aggregates.
Digital holographic microscopy
Three-dimensional optical reconstruction of aggregate morphology, volume and size distribution during flow.
Light scattering
Static and dynamic scattering measurements providing information about aggregate size, organisation and motion.
Rheological sensing
Pressure, flow or stress measurements used to derive viscosity, shear response and yield stress in microgravity.
Expected impact
Scientific relevance in space and on Earth
Spaceflight health
Improved understanding of how microgravity-induced changes in blood flow and composition may contribute to stasis, coagulation and thrombus formation.
Blood rheology models
New experimental data and kinetic models connecting red blood cell aggregation dynamics to non-Newtonian blood behaviour.
Biomedical countermeasures
Assessment of nanomaterial-based approaches that may support future strategies for managing coagulation and cardiovascular dysfunction.
Consortium
Participating organisations
KRABS brings together expertise in blood rheology, microgravity experimentation, digital holography, nanomaterials and biomedical analysis.
France · Coordinator
CNRS / Université Grenoble Alpes
Coordinator:
Thomas Podgorski
Blood sample preparation, rheological parameters and
experimental requirements.
Belgium
ULB-CREST
Science team:
Christophe Minetti
Carlo Saverio Iorio
Optical systems, experimentation and data processing.
