Multiphoton Microscopy Triplet Relaxation Scanning
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Solution Overview
Problem
Multiphoton microscopy (MPM) faces limitations due to photobleaching and photodamage, which can lead to protein denaturation, DNA damage, and oxidative stress, especially with shorter pulse widths and higher average powers.
Innovation Solution
The method involves exciting a biological sample with a rapidly scanned light source to increase triplet relaxation, while simultaneously detecting light emitted by the sample in multiple colors to create images or temporal series of images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If shorter pulse widths and higher average powers are used in multiphoton microscopy, then imaging depth and signal intensity are improved, but phototoxicity and photodamage increase
Solution Approach 1:
The patent employs periodic scanning of the laser beam across the sample at high speeds, creating a raster scan pattern. This periodic action distributes the total energy exposure over time and space, reducing the cumulative phototoxic effect while maintaining sufficient signal intensity for deep tissue imaging.
Solution Approach 2:
The patent optimizes multiple parameters including pulse width, average power, scanning speed, and repetition rate to achieve the desired balance. By dynamically adjusting these parameters, the system maintains high signal intensity for deep imaging while controlling phototoxicity through parameter optimization rather than single-parameter adjustment.
2Volume of moving object
If higher average power is used to improve imaging depth, then penetration capability increases, but photodamage and protein denaturation increase
Solution Approach 1:
The high-speed periodic scanning distributes the high average power across a large number of scan lines, reducing the energy density at any single location and minimizing photodamage while maintaining the capability to penetrate deep tissues through the cumulative effect of many scanned positions.
Solution Approach 2:
The rapid scanning speed allows the system to quickly move through the sample volume, reducing the dwell time at each location. This rushing through effect minimizes the total energy absorbed by any single region, thereby reducing photodamage and protein denaturation while maintaining imaging depth.
3Object-affected harmful factors
If rapid scanning is used to reduce phototoxicity, then triplet relaxation increases, but imaging speed and temporal resolution are limited
Solution Approach 1:
The patent optimizes the scanning speed, pulse repetition rate, and pulse width parameters to achieve the optimal balance. By carefully tuning these parameters, the system achieves sufficient triplet relaxation to reduce phototoxicity while maintaining acceptable imaging speeds and temporal resolutions for dynamic biological processes.
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 reduces phototoxicity, allowing for dynamic imaging of deep tissues without significant damage, and enables real-time monitoring of intracellular molecular metabolites like FAD, NAD(P)H, and tryptophan.
Implementation Method 1
near-infrared ('NIR') femtosecond lasers use multiple excitation photons (e.g., two or more photons) for imaging
Implementation Method 2
exciting a biological sample using a light source that is rapidly scanned over the biological sample to increase triplet relaxation in the biological sample
Implementation Method 3
simultaneously detecting light emitted by molecules in the biological sample in a plurality of colors
Data Source
AI summary
Multiphoton microscopy provides a non-invasive tool capable of monitoring metabolic states and/or the overall health of live cells with improved spatial resolution. A laser light source (e.g., a femtosecond laser) is used to excite one or more fluorophores, harmonophores, or other molecules in a biological sample and photonics are used to image, monitor, and retain cell health. Phototoxicity is reduced by rapidly scanning a laser light source over the sample such that full triplet relaxation in the sample is obtained, thereby reducing phototoxicity.