Laser Transmissivity Control of Surface Protein Denaturation
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Solution Overview
Problem
Current methods for imaging and analyzing larger proteins and formalin-fixed paraffin-embedded (FFPE) samples using MALDI-MS technology face challenges such as slow enzymatic digestion, potential contamination and delocalization issues with thermal digestion, and the need for intrusive monitoring techniques, which affect the fidelity and reproducibility of protein denaturation control.
Innovation Solution
A non-intrusive laser-based technique that uses a low-powered laser and a radiant heater to monitor protein denaturation by tracking transmissivity changes in biological samples, allowing for precise control of thermal treatment and avoiding overheating through a movable heat shield, enabling uniform and reproducible heating for MALDI-MS imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If enzymatic digestion is used to break down proteins, then proteins can be decomposed into peptides for analysis, but the reaction time is slow (hours) and product delocalization occurs
Solution Approach 1:
The patent changes the fundamental parameter of digestion mechanism from enzymatic to thermal. By applying controlled thermal energy (heating to specific temperatures for defined periods), the digestion process is accelerated from hours to minutes while maintaining spatial fidelity. The thermal parameters (temperature, time) are optimized to achieve complete protein decomposition without causing sample delocalization.
Solution Approach 2:
The patent replaces the biochemical enzymatic system with a physical thermal system. Instead of using enzymes that require regulated atmospheric and hydration conditions, the invention uses controlled heating that is less sensitive to environmental variations, thereby reducing product delocalization and simplifying the digestion process.
2Loss of time
If thermal digestion with convective heating is used, then digestion time is reduced and product delocalization is minimized, but contamination risk increases and sample disruption occurs at high gas flow rates
Solution Approach 1:
The patent replaces convective heating (which requires gas flow) with radiant heating. This substitution eliminates the need for high gas flow rates that cause sample disruption and contamination. The radiant heating system delivers thermal energy directly to the sample through radiation, achieving rapid digestion without the harmful effects of forced convection.
Solution Approach 2:
The patent introduces an intermediary heating mechanism (radiant heater) that transfers thermal energy without requiring direct contact or high-velocity gas flow. This intermediary system delivers the necessary thermal energy for digestion while avoiding the contamination and disruption issues associated with convective heating methods.
3Measurement precision
If intrusive monitoring techniques (e.g., thermocouples) are used during thermal treatment, then protein conversion can be monitored, but the effectiveness of thermal treatment is interfered with
Solution Approach 1:
The patent replaces intrusive mechanical monitoring (thermocouples that physically contact and potentially disrupt the sample) with non-intrusive optical monitoring. A laser beam passes through the sample, and changes in light transmission or absorption indicate protein conversion status. This optical method monitors the process without interfering with the thermal treatment effectiveness.
Solution Approach 2:
The patent uses light as an intermediary monitoring tool that can penetrate the sample and detect protein conversion without physically contacting or disrupting the thermal treatment process. The laser-based monitoring system provides real-time feedback while maintaining the integrity and effectiveness of the thermal digestion.
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 allows for efficient and precise control of protein denaturation, reducing contamination risks and ensuring uniform heating, thereby improving the fidelity and reproducibility of protein analysis and imaging, especially for larger proteins and FFPE samples.
Implementation Method 1
heating via a radiant heater a biological sample
Implementation Method 2
monitoring via a laser and a photodetector protein denaturation of the biological sample based on a signal voltage detected
Data Source
AI summary
A method and apparatus for monitoring and/or controlling the extent of denaturation and/or bond cleavages of proteins on any surface (e.g., biological tissues, biofilms, etc.). In one embodiment, a low power laser (e.g., a 5 mW, 362 nm diode laser) is directed through a biological sample to a photodetector. The sample is heated by a set of radiant heaters to between about 220° C. and about 250° C. in a time period of between 10 seconds to 60 seconds. The baseline transmissivity of the sample is monitored continuously throughout treatment of the biological sample via continuous monitoring of the signal voltage detected at the photodetector. Upon detection of increase in relative transmissivity in the biological sample, the heating treatment is concluded and the biological sample is removed for in situ protein identification as part of an imaging MALDI-MS measurement.