Raman Spectroscopy for Body Fluid Detection on Scattering Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting human body fluid traces, such as blood or semen, at crime scenes are hindered by interference from the substrate's light scatter, leading to false positives and the need for destructive sample preparation.
Innovation Solution
A Raman spectroscopic system that uses multivariate curve resolution combined with the additions method (MCRAD) and reducing spectrum complexity (RSC) to isolate and account for substrate interference, enabling non-destructive analysis of fluid samples on interfering substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Raman spectroscopy is used to detect body fluid traces, then detection sensitivity and specificity are improved, but substrate light scatter interference worsens measurement accuracy
Solution Approach 1:
The patent applies Multivariate Curve Resolution-Additions Method (MCR-AD) to mathematically separate the substrate scattering signal from the body fluid Raman signal. By treating the substrate interference as a distinct spectral component that can be resolved and subtracted, the method converts the harmful interference into a separable signal, enabling accurate detection of body fluids even on strongly scattering substrates like fabric and paper
Solution Approach 2:
The patent segments the composite Raman spectrum into distinct components: substrate scattering signal and body fluid signal. Through MCR-AD analysis, the total spectrum is decomposed into individual contribution profiles, allowing selective analysis of the body fluid component while excluding substrate interference
2Reliability
If conventional biochemical tests are used for body fluid detection, then detection reliability is improved, but the process becomes destructive and requires extensive sample preparation
Solution Approach 1:
The patent replaces destructive mechanical and chemical sample preparation methods with non-destructive optical spectroscopy. Instead of using biochemical reactions that consume samples (like ELISA or chromatography), the system uses Raman spectroscopy with computational analysis to identify body fluids, preserving the evidence while achieving comparable or superior reliability
Solution Approach 2:
The patent changes the detection parameter from biochemical reactivity to vibrational spectroscopy characteristics. By measuring the Raman spectral fingerprint of molecules rather than their chemical reactivity, the method achieves reliable identification without sample destruction or complex preparation procedures
3Productivity
If immunochromatographic methods are used to detect semen proteins, then detection speed is improved, but false positives increase due to protein presence in other tissues
Solution Approach 1:
The patent targets specific vibrational modes and spectral regions in the Raman spectrum that are characteristic of semen components (proteins, lipids, carbohydrates) rather than relying on general protein detection. By analyzing the unique spectral fingerprint in specific frequency ranges, the method achieves rapid detection with higher specificity, distinguishing semen from other body fluids and tissue proteins
Data Source
AI summary
A system and method for detecting human body fluid traces within a fluid sample on a substrate that interferes with the analysis of the light scatter in Raman spectroscopy. Two methods can be used to account for the light scatter: reductive removal of the scatter data from the spectroscopic data, e.g. “reducing a spectrum complexity” (RSC); and including the scatter data in the spectroscopic data and identifying it, e.g. “Multivariate curve resolution combined with the additions method” (MCRAD). The system can include a remote Raman spectrometer that can utilize locate and remote computer assets to assist in the remote detection of human body fluid traces, such as blood or semen.