LED Excitation Source for AlphaScreen Optical Measurement
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Solution Overview
Problem
Current optical measurement technologies using laser diodes for excitation in AlphaScreen and similar chemiluminescence assays face challenges such as high power consumption, heat generation, complexity, and reduced sample reusability due to temperature sensitivity, leading to limited measurement capabilities and increased costs.
Innovation Solution
Employing a Light-Emitting Diode (LED) as the excitation light source, which provides consistent optical power without temperature-related issues, allowing for multiple measurements over time and reducing background interference through confocal optics and calibrated LED emission, enabling more sensitive and reliable detection of chemiluminescence signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a laser diode is used as the excitation light source, then high power density and uniform wavelength are achieved, but heat generation and temperature sensitivity increase, requiring active cooling and reducing sample reusability
Solution Approach 1:
The patent extracts the harmful thermal effects from the excitation light source by replacing the laser diode with an LED. The LED provides sufficient excitation power without generating the same level of heat as the laser diode, eliminating the need for active cooling systems and Peltier coolers while maintaining temperature stability.
Solution Approach 2:
The patent adopts a simpler, more robust LED light source that does not require complex cooling infrastructure. While LEDs have shorter operational lifetimes compared to laser diodes, they eliminate the need for expensive cooling systems and reduce overall system complexity, making the instrument more cost-effective and easier to maintain.
2Power
If a laser diode is used as the excitation light source, then high excitation energy is achieved, but device complexity and cost increase due to required cooling systems
Solution Approach 1:
The patent removes the complex cooling subsystems (Peltier coolers, temperature control circuits, and associated hardware) by replacing the laser diode with an LED. The LED provides adequate excitation energy for AlphaScreen measurements without generating sufficient heat to require active cooling, thereby simplifying the overall instrument architecture.
Solution Approach 2:
The patent employs a simpler, more affordable LED light source that eliminates the need for expensive cooling infrastructure. Although LEDs may have shorter operational lifetimes, they significantly reduce system complexity and cost by removing temperature control mechanisms, making the instrument more accessible and easier to maintain.
3Power
If a laser diode is used for sample excitation, then high power density is achieved, but sample reusability is reduced due to photobleaching and signal degradation
Solution Approach 1:
The patent changes the key parameter of the light source from high power density (laser diode) to lower power density with sufficient total energy (LED). This parameter change reduces the photobleaching effect on the sample while still providing adequate excitation for the AlphaScreen reaction, allowing multiple measurements to be performed on the same sample over time.
4Measurement precision
If conventional fluorescence measurement is performed, then emission light detection is achieved, but background fluorescence interference reduces measurement sensitivity
Solution Approach 1:
The patent employs time-resolved measurement where the LED excitation source is pulsed and the emission signal is detected after a delay period. This periodic action allows the short-lived background fluorescence to decay before measurement, while the longer-lived chemiluminescent signal from the AlphaScreen reaction is measured, thereby improving signal-to-noise ratio and detection sensitivity.
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 LED-based system enhances measurement sensitivity, allows for multiple sample excitations without signal degradation, and reduces background noise, enabling reliable detection of lower analyte concentrations and kinetic studies with improved accuracy and cost-effectiveness.
Implementation Method 1
The liquid sample in the sample well is exposed to excitation light at a first wavelength from an LED excitation light source, which excitation light generates a collection of singlet state oxygen molecules from the liquid sample
Implementation Method 2
said singlet state oxygen molecules reacting with acceptor molecules in the liquid sample causing said acceptor molecules to emit chemiluminescence emission light at a second wavelength
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A method and an apparatus for optical measurement of a liquid sample (2) placed in a sample well (3) where the sample in the sample well is exposed to excitation light (7) at first wavelength from an excitation light source (4), which excitation light generates a collection of singlet state oxygen molecules from donor molecules in the liquid sample, said singlet state oxygen molecules reacting with acceptor molecules in the liquid sample causing said acceptor molecules to emit chemiluminescence emission light (11) at second wavelength, which second wavelength is shorter than said first wavelength, and where the emission light produced by the excitation light is measured with a detector, characterized in that the excitation light source is a LED (4).