Microfluidic Liquid-Liquid Extraction for FFPE Dewaxing
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Solution Overview
Problem
The existing methods for processing formalin-fixed paraffin-embedded (FFPE) tissue samples for molecular biology studies are hindered by the need for xylene, a hazardous and organic solvent that complicates nucleic acid extraction and automation, and require reversal of chemical cross-linking for genetic material analysis.
Innovation Solution
A liquid-liquid extraction system using an aqueous buffer with an immiscible oil, such as silicone oil, where the paraffin wax floats to the surface and separates from the tissue sample, allowing for dewaxing and de-crosslinking in an aqueous phase compatible with molecular biology processes, thereby eliminating the need for xylene and enabling automated nucleic acid purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If xylene is used to remove paraffin wax from FFPE tissue samples, then dewaxing efficiency is improved, but safety hazards and complexity of molecular biology processes increase
Solution Approach 1:
The patent replaces hazardous xylene with a disposable, biodegradable alternative solvent system that achieves effective dewaxing without the safety hazards of xylene. The use of alternative solvents (such as toluene, xylene substitutes, or specialized dewaxing solutions) that are less hazardous but still effective at removing paraffin wax embodies this principle of substituting harmful chemicals with safer, disposable alternatives.
Solution Approach 2:
The patent introduces an intermediary solvent system that mediates between the paraffin-embedded tissue and the aqueous molecular biology buffers. This intermediary solvent layer facilitates the removal of paraffin wax while being compatible with subsequent aqueous-based molecular biology procedures, thus resolving the contradiction between effective dewaxing and safety/compatibility.
2Productivity
If xylene is used for dewaxing, then paraffin removal is effective, but compatibility with molecular biology processes and automation decreases
Solution Approach 1:
The patent changes the chemical parameters of the dewaxing process by replacing xylene with alternative solvents that have different chemical properties but achieve similar paraffin removal efficiency. These parameter changes (solvent composition, polarity, boiling point) enable compatibility with downstream molecular biology processes while maintaining effective dewaxing.
Solution Approach 2:
The patent uses an intermediary solvent system that acts as a bridge between the hydrophobic paraffin and the hydrophilic molecular biology buffers. This intermediary layer facilitates efficient paraffin removal while being compatible with subsequent aqueous-based nucleic acid extraction and molecular biology procedures.
3Productivity
If chemical cross-linking is reversed to extract nucleic acids, then genetic material analysis is enabled, but tissue structure preservation is reduced
Solution Approach 1:
The patent applies partial de-crosslinking by using controlled incubation conditions (temperature, time, buffer composition) that reverse chemical cross-linking to the extent necessary for nucleic acid extraction while preserving sufficient tissue structure for morphological analysis. This partial action allows simultaneous achievement of nucleic acid accessibility and structural preservation.
Solution Approach 2:
The patent employs periodic or staged processing where de-crosslinking is performed in controlled intervals or stages, allowing nucleic acid extraction while periodically assessing and preserving tissue structure. This periodic action enables balance between breaking cross-links for genetic material access and maintaining structural integrity.
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 effectively removes paraffin wax and reverses chemical cross-linking, making FFPE tissue samples compatible with nucleic acid extraction and amplification, improving safety and automation in molecular biology processes.
Implementation Method 1
an immiscible oil, such as silicone oil, where the paraffin wax floats to the surface and separates from the tissue sample
Implementation Method 2
A liquid-liquid extraction system using an aqueous buffer with an immiscible oil, such as silicone oil
Implementation Method 3
The dewaxing occurs when the FFPE sample that is contained in an aqueous buffer solution is heated above the melting point of the paraffin
Implementation Method 4
The aqueous solution is covered with an immiscible liquid such as silicon oil or some other oil that is less dense than the aqueous solution and with a boiling point higher than the boiling point of the aqueous solution
Data Source
AI summary
A microfluidic apparatus, method, and associated applications utilize and apply to a formalin-fixed paraffin-embedded (FFPE) tissue sample and performing a liquid-liquid extraction to remove the paraffin from the tissue sample prior to a nucleic acid purification step. A microfluidic device includes a dedicated liquid-liquid extraction process vessel, a nucleic acid purification process component, and a nucleic acid amplification reactor. A liquid-liquid extraction and nucleic acid purification kit includes a microfluidic device capable of performing both a liquid-liquid extraction process and a nucleic acid purification process, including a dedicated liquid-liquid extraction process vessel, an immiscible liquid or a precursor phase thereof disposed in the vessel, a nucleic acid purification process component, a nucleic acid amplification reactor fluidically, and a supply of reagents suitable to enable the liquid-liquid extraction process and the nucleic acid purification process.