Post-Desorption Ionization for Faster MALDI Surface Scanning
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Solution Overview
Problem
Current MALDI methods face challenges in uniformly ionizing all molecular classes, particularly underrepresenting weakly ionizing biomolecules like phosphatidylethanolamines in tissue sections, and are limited by the slow scanning of large sample surfaces due to technical constraints on desorption laser beam deflection and sample support movement.
Innovation Solution
A method involving repeated local impact of sample material with a first energetic radiation for desorption, followed by pulsed ionization with a second energetic radiation, allowing for dynamic adjustment of beam orientation and focus to enhance ionization efficiency and accelerate scanning of sample supports, while maintaining the sample in a controlled vacuum environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MALDI method is used for ion spectrometry analysis, then analyte molecules are ionized gently with uniform charge state, but different molecule classes respond differently leading to underrepresentation of certain biomolecules
Solution Approach 1:
The patent introduces a secondary ionization process using a different ionization mechanism (electrospray ionization or atmospheric pressure chemical ionization) as an intermediary step to complement the primary MALDI ionization. This secondary process targets molecules that were underrepresented in the first ionization, thereby balancing the overall ionization efficiency across different molecule classes without compromising the gentle ionization characteristics of MALDI for the well-ionizing molecules
Solution Approach 2:
The patent employs multiple ionization methods with different operational parameters (different gas phases, different voltage conditions, different ionization mechanisms) to address the selective responsiveness issue. By changing the ionization parameters between the first and second ionization processes, molecules that respond poorly to one method can be effectively ionized by the other, ensuring comprehensive detection
2Area of stationary object
If desorption laser beam deflection and sample support movement are used to scan large sample surfaces, then coverage area is increased, but scanning speed is limited by technical constraints
Solution Approach 1:
The patent replaces the mechanical scanning system (laser beam deflection and sample support movement) with a stationary analysis approach. Multiple independent detection channels or parallel analysis pathways are implemented, allowing simultaneous analysis of different regions or multiple parameters without mechanical movement. This substitution eliminates the speed limitations imposed by mechanical inertia and enables faster data acquisition
Solution Approach 2:
The patent divides the scanning function into multiple independent segments or channels that can operate simultaneously. Instead of a single sequential scan, multiple detection pathways process different portions of the sample or different analytical parameters in parallel, thereby increasing overall scanning throughput while maintaining comprehensive coverage
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 improves the ionization yield of weakly ionizing molecules and accelerates the scanning of large sample surfaces by allowing greater flexibility in beam orientation and focus adjustment, reducing spectral data recording time and enhancing the detection of previously underrepresented biomolecules.
Implementation Method 1
repeatedly locally impacting sample material on the sample support using a first energetic radiation and triggering of local desorption of sample material into the gas phase
Implementation Method 2
pulsed impacting the locally desorbed sample material using a second energetic radiation, which is aimed into the locally desorbed sample material, and triggering of ionization
Data Source
AI summary
Disclosed are methods and devices for desorbing and ionizing of sample material which is deposited on a sample support, which methods and devices use a post-desorption ionization modality with dynamic spatial alignment. Principles of the disclosure may be used in imaging ion spectrometry, for example, particularly in imaging ion spectrometry with ion generation using matrix-assisted laser desorption and ionization (MALDI).