STED Microscopy Light Intensity Distribution for Reduced Phototoxicity
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Solution Overview
Problem
High-resolution imaging of samples marked with fluorescence markers faces challenges due to light-induced bleaching and phototoxicity, particularly with high-intensity light doses in STED microscopy, which can damage or devitalize living biological samples.
Innovation Solution
The method involves superimposing an intensity maximum of focused fluorescence excitation light with an intensity minimum of focused fluorescence inhibition light, enclosed by intensity maxima, to form a light intensity distribution that selectively scans partial areas of interest with the intensity minimum, terminating the light exposure when predetermined fluorescence light amounts are reached to reduce bleaching and phototoxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-intensity fluorescence inhibition light is used in STED microscopy to achieve high-resolution imaging, then spatial resolution is improved, but sample damage and phototoxicity increase
Solution Approach 1:
The patent applies local quality by creating a spatially differentiated light intensity distribution where only specific regions (the donut-shaped inhibition zone) receive high-intensity fluorescence inhibition light, while other areas receive standard excitation light. This localized application of intense light achieves high resolution at the focal point without subjecting the entire sample to damaging high-intensity illumination, thereby resolving the contradiction between resolution improvement and sample damage prevention.
2Measurement precision
If high light doses are applied to achieve high-resolution imaging, then imaging quality is improved, but fluorescence marker bleaching increases
Solution Approach 1:
The patent segments the light dosage application by dividing the illumination pattern into distinct zones: a central excitation region and a surrounding inhibition region. This segmentation allows the system to achieve high-resolution imaging through the inhibition zone while limiting the total light dose received by fluorescence markers, thereby reducing bleaching while maintaining imaging quality.
3Measurement precision
If fluorescence inhibition light is used to reduce the imaged volume, then spatial resolution is improved, but the complexity of the light intensity distribution increases
Solution Approach 1:
The patent employs periodic action through the use of pulsed or cyclic illumination patterns where the fluorescence inhibition light is applied in a rhythmic manner synchronized with the excitation light. This periodic application of complex light intensity distributions simplifies the overall system control while achieving the desired spatial resolution through the donut-shaped inhibition pattern.
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 significantly reduces the light dose to the sample, minimizing bleaching and phototoxicity while maintaining high-resolution imaging, especially in living biological samples, by optimizing the light exposure based on fluorescence activity.
Implementation Method 1
a light intensity distribution including an intensity maximum of focused fluorescence excitation light
Implementation Method 2
The fluorescence inhibition light may inhibit the fluorescence of the fluorescence markers by which the structure of interest of the sample is marked in different ways, like for example by stimulated emission in STED fluorescence microscopy
Implementation Method 3
by transferring the fluorescence markers into a dark state in which they are not able to fluoresce in RESOLFT fluorescence microscopy using switchable fluorophores
Data Source
AI summary
In methods of high-resolution imaging a structure of a sample, the structure being marked with fluorescence markers, the sample is subjected to a light intensity distribution including an intensity maximum of focused fluorescence excitation light to selectively scan partial areas of interest of the sample. Fluorescence light emitted out of the sample is registered and allocated to a respective location of the light intensity distribution in the sample. The subjection of the sample to at least one part of the light intensity distribution is terminated at each location of the light intensity distribution, if at least one criterion of the following criteria is met: (a) a predetermined maximum light amount of the fluorescence light emitted out of the sample has been registered, and (b) a predetermined minimum light amount of the fluorescence light emitted out of the sample has not been registered within a predetermined period of time.