Formaldehyde-Free Blood Stabilization for Flow Cytometry
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Solution Overview
Problem
Current methods for preparing biological samples for flow cytometry analysis, particularly for protein epitopes like Zap-70, face challenges due to rapid sample deterioration, instability, and interference from formaldehyde, leading to decreased epitope availability and inaccurate results.
Innovation Solution
A method involving a protective agent, substantially free of formaldehyde, is used to stabilize drawn blood samples by contacting them with a mixture containing imidazolidinyl urea or diazolidinyl urea as preserving agents and K3EDTA as an anticoagulant, allowing analysis of protein epitopes for up to 96 hours without compromising flow cytometry results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If formaldehyde is used to fix cells for flow cytometry analysis, then cell stability is improved, but protein epitope availability decreases and toxic effects occur
Solution Approach 1:
The patent removes formaldehyde from the fixation process entirely, extracting the harmful substance while maintaining cell stability through alternative non-formaldehyde fixation methods that preserve protein epitope integrity for flow cytometry analysis
Solution Approach 2:
The patent converts the harmful effects of formaldehyde into beneficial outcomes by using alternative fixation agents that provide both cell stability and epitope preservation, effectively transforming the problem of formaldehyde toxicity into a solution that eliminates toxicity while maintaining or improving analysis reliability
2Stability of the object's composition
If formaldehyde fixation is performed before staining, then cell stability is improved, but staining intensity decreases due to reduced epitope availability
Solution Approach 1:
The patent performs staining actions before formaldehyde fixation would normally occur, or uses alternative fixation methods that do not interfere with subsequent staining, thereby preserving epitope availability and maintaining strong staining intensity while still providing cell stability
Solution Approach 2:
The patent changes the chemical parameters of the fixation process by substituting formaldehyde with alternative fixation agents that maintain cell stability without reducing protein epitope accessibility, thereby preserving staining intensity
3Loss of time
If samples are stored for extended periods before analysis, then shipping and delayed analysis become possible, but protein expression stability decreases
Solution Approach 1:
The patent applies protective measures beforehand by using optimized fixation and preservation methods that cushion against protein degradation during extended storage, enabling stable protein expression maintenance throughout shipping and delayed analysis periods
4Ease of operation
If detergent permeabilization is used without prior fixation, then intracellular access is improved, but cell membrane integrity is destroyed and proteins are released
Solution Approach 1:
The patent performs fixation action before detergent permeabilization to stabilize cell membranes in advance, creating a foundation that allows subsequent permeabilization to proceed without complete membrane destruction or protein release, thereby maintaining controlled intracellular access
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 method provides increased stability and accuracy in detecting cell surface and intracellular markers, including Zap-70, with preserved protein expression up to 100% after four days, enabling reliable clinical assays and shipping without temperature-induced degradation.
Implementation Method 1
contacting a drawn blood sample with a protective agent that is substantially free of formaldehyde... a mixture containing imidazolidinyl urea or diazolidinyl urea as preserving agents
Data Source
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AI summary
A method relating to preparation of a biological sample for analysis by flow cytometry including contacting a drawn blood sample with a protective agent that is substantially free of formaldehyde and analyzing the white blood cells of the contacted sample for protein epitopes after at least about twenty-four hours after contacting.