Conductive Embedding Medium for Charge-Free Biological Microscopy
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Solution Overview
Problem
Current biological sample preparation methods for electron microscopy rely heavily on toxic and mutagenic heavy metal salts, which alter sample properties, cause electronic charge accumulation, and result in poor imaging quality due to contamination and biological property changes.
Innovation Solution
A novel embedding medium composed of glycol dimethacrylate, polyalkylene glycol diacrylate or methacrylate, and a radical polymerization initiator, which is electro-conductive and preserves the native fluorescence and ultrastructure of biological samples, reducing the need for heavy metal salts and improving imaging contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heavy metal salts and fixatives are used for contrast enhancement, then imaging contrast is improved, but biological properties are altered and electronic charge accumulation occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the embedding medium by using glycol dimethacrylate and polyalkylene glycol diacrylate/methacrylate with specific molecular weights and ratios, replacing traditional heavy metal-based contrast agents. This parameter change achieves adequate imaging contrast while preserving biological properties and preventing charge accumulation.
Solution Approach 2:
The patent creates a composite embedding medium combining glycol dimethacrylate (60-99 wt%) with polyalkylene glycol diacrylate or methacrylate (1-40 wt%), forming a new material system that integrates multiple functions: structural support, charge evacuation, and contrast enhancement without toxic effects.
2Measurement precision
If heavy metal salts are used for contrast enhancement, then imaging contrast is improved, but electronic charge accumulation occurs leading to halo formation
Solution Approach 1:
The patent introduces the glycol-based polymer matrix as an intermediary material that mediates between the electron beam and the biological sample. This intermediary provides charge evacuation pathways through its molecular structure, preventing charge accumulation while maintaining contrast enhancement capabilities.
Solution Approach 2:
The patent modifies the electrical properties of the embedding medium by selecting polymers with appropriate dielectric constants and charge mobility characteristics. The glycol dimethacrylate and polyalkylene glycol derivatives provide optimal electrical parameters for charge evacuation while maintaining structural integrity.
3Reliability
If traditional embedding media are used, then sample protection from vacuum is achieved, but electro-conductivity is poor leading to charge accumulation
Solution Approach 1:
The patent optimizes the electrical conductivity parameter of the embedding medium by selecting glycol-based polymers with specific molecular weights and crosslinking densities. This parameter optimization enables adequate charge evacuation while maintaining vacuum protection and structural support functions.
4Stability of the object's composition
If fixatives are used for sample preservation, then structural stability is improved, but fluorescence emission and protein activity are altered
Solution Approach 1:
The patent extracts and eliminates toxic fixative agents from the sample preparation process by using physical embedding in glycol-based polymers. This extraction approach maintains structural stability through physical entrapment rather than chemical fixation, preserving fluorescence and protein activity.
Solution Approach 2:
The patent changes the preservation mechanism from chemical fixation to physical embedding by adjusting the glass transition temperature and crosslinking density of the glycol-based polymer matrix. This parameter adjustment provides structural stability without chemical interaction that would alter biological properties.
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 embedding medium effectively evacuates electron charges, maintains sample integrity, and enhances imaging contrast, providing better preservation of biological properties and ultrastructure during microscopy analysis.
Implementation Method 1
a composition comprising or being constituted of a mixture of (i) glycol dimethacrylate, (ii) polyalkylene glycol diacrylate and/or polyalkylene glycol methacrylate, and (iii) an initiator
Implementation Method 2
the heavy metal salts only capture electrons during imaging but do not allow to discharge the electron charges accumulating on the sample surface during the realization of the microscopic cliché
Data Source
AI summary
The present invention relates to the field of microscopy, preferably electron microscopy. Especially, the present invention concerns an embedding medium for imaging a biological sample by microscopy comprising:from 60% to 99% wt. of a glycol dimethacrylate selected from alkylene glycol dimethacrylate and/or oligo(alkylene glycol) dimethacrylate;from 0% to 38% wt. of a polyalkylene glycol diacrylate or of a polyalkylene glycol methacrylate; said polyalkylene glycol diacrylate or polyalkylene glycol methacrylate being optionally substituted by at least one hydrophilic group such as hydroxyl, amino, or an oxo group;at least one additive, preferably comprising at least one heavy metal salt or lanthanide salt; andfrom 0.1% to 2% wt. of a radical polymerization initiator.The present invention also refers to the electro-conductive material resulting from the polymerization of the embedding medium of the invention, and the process and kits of preparation thereof; said material embedding at least one biological sample.The present invention also relates to a method for imaging by microscopy, a biological sample comprising using the embedding medium and/or the electro-conductive material of the invention.