Microbial MALDI Analysis via On-Medium Cell Disruption
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Solution Overview
Problem
Current methods for mass spectrometric analysis of microbes require extensive culturing times, typically 18 to 24 hours, which is inadequate for many applications, especially in medical diagnostics, and involve manual transfer methods that are inefficient and require significant consumable materials.
Innovation Solution
A method for mass spectrometric analysis that disrupts microbial cells on a nutrient medium, transfers the released proteins directly onto a contact surface of a sample support, and acquires mass spectra using MALDI or alternative ionization techniques, allowing for identification within six to eight hours, reducing the need for consumables and enabling automation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual colony transfer methods are used with traditional agar plates, then reliable microbial identification can be achieved, but the culturing time requires 18 to 24 hours and significant consumable materials are needed
Solution Approach 1:
The invention segments the culturing process by using solidification agents with different gelation times. Fast-gelling agents (gelation time ≤30 minutes) enable rapid colony formation for time-critical applications, while slow-gelling agents (gelation time ≥3 hours) provide optimal growth conditions for difficult-to-culture microbes. This segmentation allows selection of appropriate culturing durations based on specific application needs, reducing the standard 18-24 hour requirement.
Solution Approach 2:
The invention changes the physical-chemical parameters of the nutrient medium by incorporating solidification agents with varying gelation characteristics. By adjusting gelation time, temperature, pH, and composition parameters, the system optimizes colony formation speed and microbial growth conditions simultaneously, enabling reliable identification within shorter timeframes while maintaining accuracy.
2Productivity
If manual colony transfer is performed, then microbial samples can be obtained for analysis, but the process requires significant consumable materials and is inefficient
Solution Approach 1:
The invention implements self-service automation where the system automatically performs colony picking, transfer, and positioning without manual intervention. Automated robotic pickers and precision positioning systems handle the entire sample preparation workflow, eliminating the need for manual toothpick transfers and reducing consumable waste while increasing throughput and productivity.
Solution Approach 2:
The invention replaces manual mechanical transfer methods with automated robotic systems and computer-controlled positioning mechanisms. This substitution eliminates the inefficiencies of manual operation, reduces consumable material usage through precise transfer control, and significantly enhances sample preparation productivity and consistency.
3Measurement precision
If colonies are cultured to sufficient size for manual sampling (at least 0.5-1 mm diameter), then reliable microbial identification can be achieved, but this requires many hours or days of culturing
Solution Approach 1:
The invention performs preliminary enrichment of microbial samples before plating, concentrating the microbes to higher densities in the initial inoculum. This preliminary action accelerates colony formation speed, allowing colonies to reach sufficient size for reliable sampling in 6-12 hours instead of 18-24 hours, while automated picking systems can handle even smaller colonies with high precision.
Solution Approach 2:
The invention uses automated robotic systems to create precise copies of colonies by picking and transferring them to new locations or directly to analysis platforms. This copying capability allows analysis of smaller, younger colonies that would be insufficient for manual sampling, reducing the required culturing duration while maintaining identification reliability through automated precision.
4Productivity
If automated methods are implemented, then process efficiency and consistency can be improved, but device complexity increases
Solution Approach 1:
The invention designs automated systems with multi-functional components that perform multiple operations using the same hardware platform. The robotic picker system, for example, handles colony picking, transfer, positioning, and can interface with different analysis platforms, reducing overall system complexity while maintaining high productivity and consistency across diverse applications.
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 significantly shortens the time required for microbial identification to less than a day, reduces the amount of material needed, and enhances sensitivity by allowing rigorous washing of proteins, minimizing interference, and automating the process to prevent sample misassignment.
Implementation Method 1
The MALDI samples with the embedded analyte molecules are bombarded with focused UV-laser pulses of a few nanoseconds duration in a mass spectrometer, thus generating ions of the analyte molecules in the vaporization plasmas.
Implementation Method 2
The acid (usually formic acid or trifluoroacetic acid) attacks the cell walls, which means that the organic solvent (usually acetonitrile) of the matrix solution can penetrate into the microbial cells and cause their weakened cell walls to burst by osmotic pressure.
Implementation Method 3
the organic solvent (usually acetonitrile) of the matrix solution can penetrate into the microbial cells and cause their weakened cell walls to burst by osmotic pressure
Implementation Method 4
The sample is then dried by evaporating the solvent, causing the dissolved matrix material to crystallize.
Implementation Method 5
The sample is then dried by evaporating the solvent, causing the dissolved matrix material to crystallize.
Data Source
AI summary
The invention relates to the cell disruption of microbes and the preparation of the microbe proteins for mass spectrometric analysis. The cells of microbes from microcolonies are disrupted by physical or chemical means directly on the nutrient medium. The released proteins are then transferred to sample supports by direct contact with their contact surfaces; electrophoresis can be used for assistance. Once the proteins are firmly adsorbed on the contact surfaces, they can be washed with water in order to remove substances which interfere with the ionization process. For analysis by matrix-assisted laser desorption (MALDI), the proteins are prepared on the contact surfaces of the sample supports with matrix substances to form MALDI samples; the sample supports are then introduced into a MALDI mass spectrometer for the acquisition of mass spectra. The microbes are identified by similarity comparisons between the mass spectra of the microbe proteins and similarly obtained reference spectra.