Broadband LED Optical System for Biological Analysis
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Solution Overview
Problem
Optical systems for biological and biochemical reactions face challenges in providing high optical performance with small sample signals from increasing numbers of reactions, particularly in microtiter plates and digital PCR, which require smaller sample volumes and higher sensitivity.
Innovation Solution
The system employs a broadband LED excitation source with a spectral profile optimized for maximum intensity at wavelengths less than 600 nanometers, combined with a modular filter assembly and optical elements like lenses and beam splitters to enhance optical power and reduce infrared noise, allowing for efficient processing of biological samples across various sample sizes and formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of sample sites is increased to accommodate more reactions simultaneously, then productivity is improved, but the sample volume per site decreases and optical performance deteriorates
Solution Approach 1:
The system segments the optical detection function by using separate excitation and emission optical paths with dedicated filters and detectors for each. This allows independent optimization of each detection channel, maintaining high sensitivity even when detecting from multiple small sample sites simultaneously in microtiter plates.
Solution Approach 2:
The patent changes the spectral parameters of the excitation source by using broadband LEDs with peak emission at specific wavelengths (e.g., 470nm, 530nm, 630nm) that match the excitation maxima of common fluorescent dyes. This parameter optimization ensures maximum excitation efficiency while minimizing background noise, thereby maintaining measurement precision across numerous small sample volumes.
2Productivity
If smaller sample volumes are used to increase the number of test samples, then productivity is improved, but the sample signal strength decreases
Solution Approach 1:
The system introduces highly sensitive fluorescent dyes and molecular beacons as intermediaries that amplify the detection signal. These fluorescent probes bind specifically to target sequences and emit strong fluorescent signals upon excitation, enabling detection of minute quantities of DNA in small sample volumes with high sensitivity.
Solution Approach 2:
The patent employs periodic temperature cycling in real-time PCR to denature and anneal DNA sequences repeatedly. This periodic action allows exponential amplification of target DNA, generating sufficient fluorescent signal from extremely small initial sample volumes containing zero or one target molecule, as required for digital PCR applications.
3Adaptability or versatility
If broadband LED excitation is used to cover multiple wavelengths, then adaptability is improved, but infrared noise increases
Solution Approach 1:
The system extracts and removes the harmful infrared component from the broadband LED excitation light using infrared-blocking filters positioned in the excitation optical path. This extraction of the problematic wavelength range allows the system to maintain the advantages of broadband excitation (versatility across multiple dyes) while eliminating the detrimental infrared noise that would otherwise interfere with detection.
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 configuration enables effective data collection from both small and large sample volumes, reducing infrared noise and maintaining high image quality, thus supporting real-time PCR and digital PCR processes with improved sensitivity and efficiency.
Implementation Method 1
a broadband LED excitation source with a spectral profile optimized for maximum intensity at wavelengths less than 600 nanometers
Implementation Method 2
an optical excitation beam may be used in real-time PCR (qPCR) reactions to illuminate hybridization probes or molecular beacons to provide fluorescent signals
Implementation Method 3
optical elements like lenses and beam splitters to enhance optical power and reduce infrared noise
Data Source
AI summary
A method of analyzing a plurality of biological sample volumes comprises emitting, along an excitation optical path toward a sample holder holding the plurality of biological sample volumes, electromagnetic radiation from a broadband LED, wherein the broadband LED emits the electromagnetic radiation across a range of wavelengths at a total output power of at least 5 watts and at a maximum intensity at a wavelength less than 600 nanometers and at an intensity less than 30 percent of the maximum intensity at a wavelength of 650 or 670 nanometers, and receiving, by a sensor, an electromagnetic emission transmitted from the sample holder along an emission optical path.