Fluorescence Correlation Spectroscopy with Threshold-Guided Pre-Bleaching
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Solution Overview
Problem
Existing fluorescence correlation spectroscopy (FCS) methods face challenges in efficiently reducing bleaching effects of immobile molecules, which require user expertise for bleaching time selection or alter measurement data with mathematical filters, leading to inefficiencies and potential measurement inaccuracies.
Innovation Solution
An FCS method that adapts excitation radiation wavelength, intensity, and duration based on known molecules, continuously monitors fluorescence intensity, and sets a threshold value to initiate FCS measurement data acquisition, using detectors like Airyscan or SPAD arrays to track intensity changes and apply decay functions for bleaching control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual bleaching time selection is used based on user experience, then bleaching effectiveness can be achieved, but the method requires high user expertise and time buffer selection is arbitrary
Solution Approach 1:
The system automatically determines bleaching completion by monitoring fluorescence intensity and comparing it to threshold values, eliminating the need for user expertise in selecting bleaching duration. The method serves itself by using the sample's own fluorescence signal as the control criterion.
Solution Approach 2:
The system continuously monitors fluorescence intensity during bleaching and uses this feedback to determine when bleaching is complete. The threshold-based comparison provides real-time feedback control, automatically adjusting the bleaching process without user intervention.
2Reliability
If sufficiently large time safety buffer is selected for bleaching, then reliable bleaching is achieved, but the FCS measurement process is unnecessarily lengthened
Solution Approach 1:
The system uses real-time fluorescence intensity monitoring with threshold comparison to determine exact bleaching completion, eliminating the need for arbitrary time buffers. The measurement starts immediately when the threshold is reached, optimizing the timeline without sacrificing reliability.
Solution Approach 2:
The bleaching time is dynamically adjusted based on the actual fluorescence decay of each sample rather than using a fixed time buffer. This allows the process to adapt to different sample characteristics and complete exactly when needed.
3Object-affected harmful factors
If mathematical filters are used to remove bleaching effects from measurement data, then bleaching disruption is reduced, but the measurement data are changed and results may be falsified
Solution Approach 1:
The system performs bleaching before the actual FCS measurement, separating the bleaching process from the measurement process. This preliminary action eliminates the need for post-processing filters that could alter data, preserving measurement authenticity.
Solution Approach 2:
The harmful bleaching effect is extracted and addressed separately before measurement begins. By removing immobile molecules during a dedicated pre-bleaching phase, the subsequent measurement data remains uncontaminated and authentic.
4Object-affected harmful factors
If mathematical filters with suitable parameterization are used, then bleaching effects can be removed, but the procedure becomes complex
Solution Approach 1:
Bleaching is performed as a preliminary step before measurement, eliminating the need for complex post-processing filters. This simple temporal separation avoids the complexity of parameterizing mathematical filters while effectively removing bleaching effects.
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 method improves the efficiency and accuracy of FCS measurements by automating bleaching control, enhancing equipment utilization, and ensuring consistent data quality across samples, reducing unnecessary sample load and idle times.
Implementation Method 1
A sample to be measured having fluorescent markers is illuminated with excitation radiation in order to bleach at least a portion of the fluorescent markers. Fluorescence radiation emitted due to the effect of the excitation radiation is detected as detection radiation
Implementation Method 2
The wavelength of the excitation radiation is chosen such that the sufficiently strongly illuminated molecules permanently lose their ability to emit fluorescence radiation, i.e. are bleached
Data Source
AI summary
An FCS method, in which a sample that is to be measured and has fluorescent markers, illuminates the sample with excitation radiation over a bleaching time in order to bleach selected fluorescent markers. After bleaching has been carried out over at least one measurement period, FCS measurement data of the sample are acquired by illuminating the sample with excitation radiation and by detecting detection radiation brought about by the excitation radiation. During the bleaching time, intensity values of fluorescence radiation that has been brought about by the excitation radiation which is directed at the sample for bleaching purposes are continuously or repeatedly acquired and compared with a threshold value, and the acquisition of the FCS measurement data is started when the threshold value has been reached.