Microfluidic Plasma Layer Optical Analyte Detection

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Solution Overview

Problem

Current methods for determining analyte concentration in whole blood are hindered by hemolysis, which alters blood plasma composition and requires time-consuming plasma separation, making it difficult to detect analytes like extracellular hemoglobin efficiently.

Innovation Solution

A method utilizing the Fahraeus effect to generate a plasma layer in a microfluidic channel, where light is directed and reflected, allowing for the analysis of analyte concentration without separating blood plasma from whole blood, using index matching substances to ensure light interaction with the plasma layer and not the channel surface, and capturing the reflected light to determine the analyte concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If plasma separation is performed to detect analyte concentration, then measurement precision is improved, but loss of time increases

Engineering Contradiction:

Improveanalyte concentration detection accuracyVSAvoidtime for plasma separation

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The invention segments the whole blood sample into different layers (plasma layer and cell layer) using the Fahraeus effect in a microfluidic channel. This segmentation allows direct optical measurement of the plasma layer without requiring complete separation, thus reducing time loss while maintaining measurement precision for analyte concentration detection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention extracts only the necessary plasma layer containing the analyte from the whole blood sample using the Fahraeus effect, rather than performing complete plasma separation. This extraction approach enables direct measurement of analyte concentration in the plasma layer while minimizing time consumption associated with full separation procedures.

Inventive Principle:

Principle #2Taking out (Extraction)

2Quantity of substance

If hemolysis occurs in whole blood, then analyte concentration changes, but measurement reliability deteriorates

Engineering Contradiction:

Improveanalyte concentrationVSAvoidblood sample usability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention converts the harmful effect of hemolysis (which releases intracellular contents into plasma) into a beneficial measurement opportunity. By using the Fahraeus effect to separate and measure the plasma layer optically, the system can detect and quantify hemolysis-induced changes in analyte concentration, transforming a quality degradation into a measurable signal for reliability assessment.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If light is directed through whole blood, then analyte detection is possible, but light scattering from blood cells interferes with measurement

Engineering Contradiction:

Improveanalyte concentration detectionVSAvoidlight scattering interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention segments the whole blood into a plasma layer and a cell layer using the Fahraeus effect in a microfluidic channel. By directing light through only the plasma layer (which is free of blood cells), the measurement achieves high precision for analyte concentration detection without interference from light scattering caused by blood cells.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The microfluidic channel structure acts as an intermediary that uses the Fahraeus effect to create a cell-free plasma layer at the channel walls. This intermediary structure enables light to interact with the plasma layer without encountering blood cells, thereby eliminating light scattering interference while maintaining measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables fast, cost-effective detection of analyte concentration in whole blood samples with minimal sample volume and no additional reagents required, allowing for accurate measurement of hemolysis without interference from blood cells.

Implementation Method 1

exposing the plasma layer to light. Furthermore, the method includes capturing light reflected from the plasma layer

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

A method utilizing the Fahraeus effect to generate a plasma layer in a microfluidic channel

Methodology Applied

Scientific EffectFahraeus effect:

Data Source

PatentEP4134657A1Device for determining the concentration of an analyte in whole blood

Publication Date: 2023.02.15 SIEMENS HEALTHCARE DIAGNOSTICS INC

Figure 1
Figure 2A~2B
Figure 3A~3B

AI summary

A device for determining the concentration of an analyte in whole blood is disclosed. A plasma layer (302, 308) is generated in the whole blood sample. Furthermore, the the plasma layer (302) is exposed to light (303, 304). Light (305) reflected from the plasma layer (302) is captured. Additionally, the reflected light (305) is analyzed to determine the concentration of the analyte. A device for determining the concentration of an analyte in a whole blood sample comprises a channel (309) configured to carry whole blood; a light source configured to direct light (303) on the channel (309); and an optical fiber (301), wherein within the optical fiber (301) the light (303) is reflected multiple times to form reflected light (304), the optical fiber (301) being located inside the channel (309) and extending in parallel with the channel (309).