RBC Deformability Measurement via Tank-Treading Motion Analysis

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Solution Overview

Problem

Current methods for assessing red blood cell (RBC) deformability are inadequate, as they often rely on simplistic parameters and are not suitable for detecting changes due to diseases or physiological modifications, limiting their ability to predict complications associated with blood circulation disorders.

Innovation Solution

A method involving the measurement of tank-treading motion in RBCs, which is sensitive to mechanical parameters and deformability, by comparing the proportion of tank-treading RBCs in a sample to reference populations, allowing for the determination of significant variations in deformability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single mechanical parameter (e.g., cell elongation under high shear stress) is used to assess RBC deformability, then the measurement is simple, but it is too simplistic and inappropriate to correlate to the ability of RBCs to correctly circulate in the microvasculature

Engineering Contradiction:

Improvesimplicity of measurementVSAvoidaccuracy of deformability assessment

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The invention changes the measured parameter from simple cell elongation under high shear stress to the proportion of RBCs exhibiting tank-treading motion under moderate shear flow conditions (1-100 s^-1). This parameter change provides a more accurate correlation with microcirculatory function while maintaining measurement simplicity through automated image analysis

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention transitions from static or single-state measurements to dynamic observation of RBC motion regimes. By observing the dynamic tank-treading motion where the RBC membrane rotates around its circumference while the cell axis remains relatively stationary, the method captures the complex deformability behavior needed for accurate microcirculatory correlation

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If complex mechanical parameters (shear elasticity, viscosity, surface area to volume ratio) are measured to accurately assess RBC deformability, then the measurement precision is improved, but the experimental measurability and device complexity increase significantly

Engineering Contradiction:

Improveaccuracy of deformability assessmentVSAvoidcomplexity of measurement system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts the essential deformability information from the complex mechanical parameters by observing the macroscopic tank-treading motion behavior. Instead of measuring shear elasticity, viscosity, and surface area to volume ratio separately, the method extracts a single integrated parameter (proportion of tank-treading RBCs) that reflects the combined effect of these mechanical properties

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces complex mechanical measurement systems with an optical observation system. Instead of using rheometers or other sophisticated mechanical apparatus to measure shear elasticity and viscosity, the method uses microscopy and image analysis to observe and quantify tank-treading motion, significantly simplifying the measurement system

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If RBC deformability is assessed using traditional methods, then the measurement can be performed, but the ability to detect changes due to diseases or physiological modifications is limited

Engineering Contradiction:

Improvefeasibility of measurementVSAvoidsensitivity to disease detection

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The invention establishes reference ranges for the proportion of tank-treading RBCs in healthy populations before applying the method to disease detection. By pre-defining what constitutes normal deformability (criterion of at least 50% tank-treading RBCs), the method enables reliable detection of pathological changes without requiring complex diagnostic algorithms

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the tracking of RBC deformability changes and prediction of complications such as vaso-occlusive crises in sickle cell disease, providing a non-invasive and cost-effective means for monitoring and diagnosing blood disorders.

Implementation Method 1

under moderate shear flows, RBCs display a large variety of regimes of motion among which typical tumbling, rolling and tank-treading motions

Methodology Applied

Scientific EffectShear flow: Couette Flow

Implementation Method 2

the regime of motion observed at a given shear stress was governed by the cell deformability

Methodology Applied

Scientific EffectShear stress: Shear Stress

Data Source

PatentUS20220341912A1Method and device for determining red blood cells deformability

Publication Date: 2022.10.27 CENT NAT DE LA RECH SCI (C N R S)

AI summary

The invention is related to a method for measuring the variability of the red blood cells deformability of an individual by determining the amount of red blood cells having a tank-treading motion in a population of red blood cells from a tested blood sample of said individual, and comparing the amount to a reference amount. The determination of the amount of red blood cells having a tank-treading motion is carried out using a visualisation means such as a brightfield microscope.