Phase Balanced Frequency Multiplication Modulation for Fluorescence Detection
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Solution Overview
Problem
Traditional time-resolved fluorescence detection methods face interference from ambient background fluorescence and impurity-stimulated fluorescence, leading to uncertain control over fluorescence detection delays and incomplete cancellation of interference signals, particularly ambient bias light and electromagnetic interference.
Innovation Solution
A method utilizing phase balanced frequency multiplication modulation, where a stimulating light source modulated by a baseband signal triggers fluorescence, and a frequency-doubled signal is used to sample and process fluorescence intensity signals, allowing for the cancellation of interference by dividing emission and decay periods and calculating integral areas to obtain a total fluorescence intensity value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional time-resolved fluorescence detection method is used with delay period, then impurity-stimulated fluorescence interference is partially canceled, but ambient bias light interference cannot be canceled and control over fluorescence detection delay is uncertain
Solution Approach 1:
The patent applies periodic modulation to the exciting light source at a specific frequency, causing the fluorescent pigment to emit modulated fluorescence. By using periodic action at twice the modulation frequency, the system can distinguish between modulated fluorescence signal and non-modulated ambient bias light interference, enabling effective cancellation of the latter while maintaining precise detection of the former
Solution Approach 2:
The patent uses a frequency-doubled signal to create a reference copy of the modulation pattern. This reference signal is used to generate in-phase and quadrature components that represent the expected fluorescence signal pattern. By comparing the actual detected signal with this reference copy, the system can accurately extract the fluorescence signal while canceling ambient bias light interference
2Measurement precision
If fluorescence detection is delayed to wait for impurity fluorescence quenching, then impurity-stimulated fluorescence impact is canceled, but uncertainty in interfering substance behavior makes complete cancellation impossible
Solution Approach 1:
Instead of relying on time-delay quenching which has uncertain effectiveness, the patent uses periodic modulation of the exciting light source. This causes the fluorescent pigment to emit modulated fluorescence at twice the modulation frequency. By detecting only at this specific frequency, the system reliably distinguishes the target fluorescence signal from impurity fluorescence and other interferences, achieving complete and reliable cancellation regardless of interfering substance behavior
Solution Approach 2:
The patent replaces the mechanical time-delay approach with a frequency-based detection method. Instead of waiting for temporal separation of signals, the system uses frequency multiplication and phase-sensitive detection to separate the modulated fluorescence signal from unmodulated or differently-modulated interference signals, providing more reliable and complete interference cancellation
3Illumination intensity
If traditional detection method is used, then simple operation is maintained, but signal intensity in fluorescence measurement is reduced due to interference
Solution Approach 1:
The patent modulates the exciting light source periodically at frequency X, causing the fluorescent pigment to emit fluorescence at twice this frequency. By detecting the fluorescence signal at this specific doubled frequency using frequency multiplication, the system can distinguish the modulated signal from the substrate's auto-fluorescence which does not follow the same modulation pattern, thereby enhancing the effective signal intensity while canceling substrate interference
Solution Approach 2:
The system creates a reference copy of the modulation pattern through frequency doubling and generates in-phase and quadrature components. This reference is used in phase-sensitive detection to extract the modulated fluorescence signal while rejecting unmodulated or differently-modulated signals such as substrate fluorescence, effectively enhancing the measured signal intensity
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 approach enhances signal intensity in fluorescence measurements by effectively canceling substrate interference, ambient bias light, and power-frequency interference, providing more accurate and reliable concentration values of the target.
Implementation Method 1
stimulating, by irradiating the sample using stimulating light, the fluorescent pigment to emit fluorescence
Implementation Method 2
A time-resolved fluorescence (Time-resolved fluorescence, TRF) immunochromatography technology is developed
Data Source
AI summary
The present invention relates to a method for detecting time-resolved fluorescence based on a principle of phase balanced frequency multiplication modulation. A stimulating light source modulated by using a baseband signal acts on a to-be-measured target to trigger fluorescence, so that the fluorescence intensifies and decays periodically; then, a frequency-doubled square signal is used to control a sampling period and divide an ascending period of the fluorescence into two and a decay period of the fluorescence into two; after independent sampling is performed separately, sampling differences of the two parts are separately calculated and then added to obtain an intensity representative value of a fluorescence signal and to obtain a concentration value of the to-be-measured target. The method in the present invention can not only likewise cancel fluorescence interference of a substrate in a sample, but also can cancel ambient bias light, power-frequency interference of a spatial electromagnetic wave or other signals, and therefore improves signal intensity in fluorescence measurement on the detection sample, has an advantage that cannot be accomplished in a conventional time-resolved fluorescence method, and can be applied in fluorescence intensity detection of a target in fields such as biology, chemistry, and medicine.