Flexible NIR Spectroscopic Sensor for Skin and Fat Interference

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Solution Overview

Problem

Existing spectroscopic sensors face challenges in accurately measuring near-infrared spectra of tissues, particularly due to interference from skin and fat layers, which affects the determination of sample properties.

Innovation Solution

The development of circuit board-based sensors that include multiple radiation sources, a spectral detector, and an electronic processor. These sensors use long-distance and short-distance radiation sources to illuminate samples, allowing for the measurement of absorbance spectra and correction for spectral contributions from skin and fat layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If long-distance radiation sources are used to illuminate the sample, then the spectral contributions from muscle tissues can be obtained, but the interference from skin and fat layers increases

Engineering Contradiction:
Improvespectral measurement accuracyVSAvoidinterference from skin and fat layers
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sensor divides the measurement into multiple segments by using both short-distance and long-distance radiation sources. The short-distance sources measure only skin and fat layers, while long-distance sources measure both skin/fat and muscle tissues. This segmentation allows separate measurement and subsequent subtraction of interfering components to isolate the target muscle tissue spectrum.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful spectral contributions from skin and fat layers are extracted and isolated using short-distance radiation sources. By measuring the spectrum at short distance (where only skin and fat contribute) and subtracting this extracted interference from the long-distance measurement, the pure muscle tissue spectrum can be obtained.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If multiple radiation sources at different distances are used, then the interference from skin and fat layers can be corrected, but the device complexity increases

Engineering Contradiction:
Improvespectral measurement accuracyVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor achieves multi-functionality by integrating both short-distance and long-distance radiation sources into a single device. This universal sensor can perform both the interference measurement (short distance) and the target measurement (long distance), eliminating the need for separate devices and simplifying the overall system architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sensor merges multiple radiation sources at different distances with a single spectral detector and processing unit into one integrated device. This combination allows simultaneous or sequential acquisition of both short-distance and long-distance spectra, enabling interference correction without requiring multiple separate instruments.

Inventive Principle:
Principle #5Merging (Combining)

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

The sensors enable accurate determination of sample properties such as oxygen saturation, hemoglobin concentration, and water content by effectively reducing the interference from overlying skin and fat layers, thereby improving the precision of near-infrared spectroscopy.

Implementation Method 1

Near-infrared radiation can generally pass through layers of skin and fat to illuminate blood vessels in muscle tissues

Methodology Applied
Scientific EffectNear-infrared radiation transmission: Infrared Radiation

Implementation Method 2

The radiation can be absorbed by hemoglobin in red blood cells

Methodology Applied
Scientific EffectAbsorption by hemoglobin: Absorption (EM radiation)

Implementation Method 3

The radiation can be absorbed by hemoglobin in red blood cells, myoglobin in muscle fibers

Methodology Applied
Scientific EffectAbsorption by myoglobin: Absorption (EM radiation)

Implementation Method 4

Radiation is scattered by both muscle fibers and blood cells, and the scattered radiation can be detected and analyzed to determine the wavelength dependence of the scattered radiation

Methodology Applied
Scientific EffectScattering of radiation: Scattering

Implementation Method 5

The absorbance spectrum of the various absorbing components in muscle tissues can be determined by comparing the spectra of incident radiation delivered to the tissues and the scattered radiation from the tissues

Methodology Applied
Scientific EffectAbsorbance spectrum determination: Absorption Spectroscopy

Data Source

PatentEP3556291B1Spectroscopic sensors
Publication Date: 2025.05.14 UNIV OF MASSACHUSETTS
  • EP3556291B1 patent drawingFigure 1A~2
  • EP3556291B1 patent drawingFigure 3A~3B
  • EP3556291B1 patent drawingFigure 4~6B

AI summary

Disclosed herein are sensors that include a flexible mounting member comprising an adhesive surface configured to attach directly to a sample and to assume a shape corresponding to at least a portion of the sample when it attaches to the sample; and a plurality of radiation sources, a spectral detector, and an electronic processor attached to the mounting member, wherein the electronic processor is configured to cause at least two of the radiation sources to direct incident radiation to a sample, to cause the spectral detector to analyze radiation from the sample, and to determine one or more properties of the sample based on the radiation from the sample.