Photoswitchable Fluorescence Detection via Antiphase Modulation
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Solution Overview
Problem
Current methods for detecting reversibly photoswitchable fluorescent species are limited by high-frequency diffusion/auto-fluorescence noise, difficulty in selectively imaging multiple fluorophores due to overlapping emission spectra, and lack of quantitative concentration measurement.
Innovation Solution
A method involving illumination with two monochromatic lights of different wavelengths to modulate the fluorescent species, allowing for phase-sensitive detection of the emitted fluorescence components, enabling selective and quantitative imaging of multiple fluorescent probes by minimizing noise and optimizing photochemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fluorescence detection methods are used, then the detection process is simple, but the signal is drowned out by intense background noise from auto-fluorescence and diffusion
Solution Approach 1:
The patent applies periodic modulation of the excitation light source at a specific frequency to induce corresponding periodic fluctuations in the fluorescence signal. By detecting the signal at this modulation frequency using lock-in amplification, the method selectively extracts the photoswitchable fluorophore signal while rejecting background noise from auto-fluorescence and diffusion that do not oscillate at the same frequency.
2Adaptability or versatility
If the spectral band width of fluorophores is used for detection, then the detection method is straightforward, but it is difficult to selectively detect more than four fluorescent markers due to overlapping emission spectra
Solution Approach 1:
The patent transitions from spectral dimension separation to temporal dimension separation. Instead of relying on different emission wavelengths, the method uses different photoswitching kinetics (different characteristic times for transitioning between fluorescent and non-fluorescent states) to distinguish multiple fluorophores. This temporal dimension allows selective detection of multiple fluorophores by detecting their fluorescence at different time points or with different modulation frequencies.
3Speed
If reversibly photoswitchable fluorescent probes with thermal transition are used, then the photochemical reaction occurs, but the characteristic transition time of 5 to 10 seconds is too long for high-frequency imaging applications
Solution Approach 1:
The patent uses periodic modulation of the excitation light source at high frequencies to drive the photoswitching process. This periodic excitation enables the fluorophores to transition between states rapidly, following the modulation frequency, thereby achieving high-speed imaging. The method optimizes the balance between transition speed and energy consumption by selecting appropriate modulation frequencies and light intensities.
4Reliability
If heterodyne excitation with two monochrome laser sources is used, then photochemical reactions are enhanced, but the signal-to-noise ratio is not optimal and empirical selection of parameters makes it difficult to transpose to other species
Solution Approach 1:
The patent systematically optimizes key parameters including modulation frequency, light intensity, and detection phase to maximize the signal-to-noise ratio. By establishing optimal parameter ranges through theoretical analysis and experimental validation, the method achieves high signal-to-noise ratio while maintaining ease of application across different photoswitchable fluorophore species.
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 effectively discriminates between different fluorophores, reduces noise interference, and provides quantitative concentration information, enhancing the sensitivity and specificity of fluorescence imaging.
Implementation Method 1
a sample E is illuminated with a first illumination light FEX1... The reversibly photoswitchable fluorescent species P exhibits two different states that can be exchanged under the influence of light... emits fluorescence radiation FLU
Implementation Method 2
The component of the intensity emitted by the fluorophores at the same pulse is then detected, in quadrature phase with respect to the excitation wave
Data Source
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AI summary
The present invention relates to a method for detecting a fluorescent species (P) that is reversibly photoswitchable at a high frequency, and more specifically to a method for detecting at least one reversibly photoswitchable fluorescent species, comprising a step of illuminating a sample containing a reversibly photoswitchable fluorescent species with a first illumination light (FEX1), of wavelength λ1, and periodically modulated at a pulsation ω and with a second illumination light (FEX2), of wavelength λ2, different from λ1, periodically modulated at a pulsation ω, the second illumination light being modulated in antiphase with respect to said first illumination light.