Pulse-illuminated Edge Deduction Microscopy for Live Cell Imaging
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Solution Overview
Problem
Current optical microscopy techniques, such as confocal and super-resolution methods like STED and FED, face limitations in spatial resolution, require high laser power, are costly, and are not suitable for live cell imaging due to sample damage and complex dye requirements, while also having issues with temporal resolution and stability.
Innovation Solution
An optical microscopy system using an optical multiplexer with a beam splitter and combiner to create out-of-phase pulsed beams of different profiles, processed by a signal processor to achieve super-resolution imaging without high laser power or specialized dyes, utilizing a single laser wavelength and minimizing sample toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If STED microscopy is used to achieve high spatial resolution, then spatial resolution is improved to 30-80 nm, but sample damage increases due to high laser power requirements
Solution Approach 1:
The patent segments the illumination process into multiple sequential pulses with different temporal profiles (e.g., Gaussian and inverted Gaussian profiles) rather than using a single high-power continuous or pulsed beam. This temporal segmentation allows the system to achieve super-resolution through differential detection of multiple lower-power pulses, thereby reducing peak power exposure and sample damage while maintaining spatial resolution improvement.
Solution Approach 2:
The patent employs periodic pulsed illumination with alternating beam profiles (e.g., alternating between Gaussian and inverted Gaussian profiles across multiple pulses). This periodic action enables temporal differentiation of signals from different focal volumes, achieving super-resolution through time-resolved detection while keeping individual pulse powers low enough to avoid sample damage.
2Adaptability or versatility
If multiple lasers with different wavelengths are used in STED, then spectral properties of dyes can be optimized, but device complexity and cost increase
Solution Approach 1:
The patent makes a single laser source perform multiple functions by using optical modulators and spatial light modulators to dynamically shape the temporal and spatial profiles of pulses from one laser wavelength. This single laser can sequentially provide different illumination profiles (Gaussian, inverted Gaussian, Bessel, etc.) that would traditionally require multiple specialized lasers, thereby reducing device complexity while maintaining versatility in matching dye properties.
Solution Approach 2:
The patent changes temporal and spatial parameters of a single laser beam using modulators rather than changing laser wavelengths. By dynamically adjusting pulse duration, temporal profile, and spatial distribution of a single laser source, the system achieves the functional equivalence of multiple lasers with different wavelengths, reducing system complexity while maintaining adaptability to different dye characteristics.
3Measurement precision
If FED microscopy is used to improve image quality, then image quality may be enhanced, but temporal resolution deteriorates due to frame-to-frame subtraction requiring multiple scans
Solution Approach 1:
The patent uses periodic pulsed illumination with alternating profiles within a single scan or even within a single pulse train, rather than requiring multiple complete frame scans. The temporal separation of different beam profile signals occurs at the pulse level, enabling differential detection without the temporal delays inherent in frame-to-frame subtraction methods, thus maintaining high temporal resolution while improving image quality.
Solution Approach 2:
The patent performs the differential measurement action within the same scan by sequentially delivering pulses with different profiles and detecting their signals in temporal sequence. This preliminary action of differentiating signals during the scanning process itself, rather than requiring post-scan frame subtraction, eliminates the temporal resolution loss associated with waiting for complete frame acquisitions and subsequent computational subtraction.
4Measurement precision
If high laser power is used to achieve super-resolution, then spatial resolution is improved, but sample toxicity increases making live cell imaging difficult
Solution Approach 1:
The patent segments the total illumination energy into multiple low-power pulses with different temporal profiles rather than using a single high-power illumination. This segmentation in the temporal domain allows the system to accumulate signal from multiple pulses while keeping peak power low, achieving super-resolution through differential detection without exposing the sample to toxic levels of laser power.
Solution Approach 2:
The patent maintains continuous scanning and signal accumulation while using low-power pulsed illumination with alternating profiles. The useful action of image formation continues uninterrupted through sequential detection of signals from multiple low-power pulses, achieving super-resolution without the need for high peak powers that would cause sample photodamage or toxicity during live cell imaging.
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
The system achieves improved spatial resolution of about 120 nm or less, reducing sample damage and cost, while allowing for versatile, high-speed, and low-toxicity imaging of live cells with minimal dye requirements, enhancing biological research capabilities.
Implementation Method 1
The optical multiplexer can include beam splitter and a beam combiner. A first light path and a second light path are defined between the beam splitter and the beam combiner
Implementation Method 2
An optical multiplexer can also include a phase plate, e.g., an optical vortex phase plate, in one of the first and second light paths that modifies the profile of a light beam traveling on that path
Implementation Method 3
The first and second pulsed beams, which are now out of phase with one another, are multiplexed to form a single pulsed beam that is directed at a sample
Data Source
AI summary
Devices and methods for super-resolution optical microscopy are described. Devices include an optical multiplexer to develop an excitation/illumination optical beam that includes alternating pulses of different profiles. Devices also include a signal processing unit to process a sample response to excitation/illumination beam and to subtract the neighboring pulses of the different profiles from one another on a pulse-to-pulse basis. Devices can be incorporated in existing confocal microscopy designs. As the subtraction effectively reduces the volume of the response signal, the spatial resolution of the systems can be markedly improved as compared to previously known optical microscopy approaches.