Covalent Dye Labeling for Microfluidic Electrophoresis
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Solution Overview
Problem
Existing microfluidic chip technologies face challenges in enhancing detection sensitivity due to high background fluorescence during electrophoretic separation and detection, requiring cumbersome destaining procedures and limitations on electric currents.
Innovation Solution
The method involves covalent dye labeling of sample compounds using reactive dye species with functional groups that form bonds with specific sample compounds, reducing background fluorescence and allowing for higher conductivity background buffers, thereby improving signal-to-noise ratios and eliminating the need for destaining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional staining procedures are used, then sample compounds can be detected, but background fluorescence is high which reduces detection sensitivity
Solution Approach 1:
The invention applies preliminary action by performing covalent dye labeling of sample compounds before electrophoretic separation. The reactive dye species are introduced to the sample solution prior to loading onto the microfluidic chip, allowing the labeling reaction to occur in advance. This preliminary labeling step ensures that only labeled sample compounds enter the separation channel, eliminating background fluorescence from unlabeled species and enabling high-sensitivity detection without requiring post-separation destaining steps.
Solution Approach 2:
The invention utilizes parameter changes by employing high conductivity background buffers with increased ionic strength to enhance the stacking effect. By adjusting the buffer composition and ionic parameters, sample compounds are concentrated at the interface between sample and background buffer during electrophoresis. This parameter optimization increases the local concentration of labeled sample compounds at the detection point, thereby improving signal-to-noise ratio and detection sensitivity while maintaining low background fluorescence.
2Measurement precision
If destaining procedures are implemented to reduce background fluorescence, then detection sensitivity improves, but the analysis procedure becomes more complex and time-consuming
Solution Approach 1:
The invention eliminates the need for post-separation destaining by performing the labeling action beforehand. Covalent dye labeling is completed during sample preparation prior to chip loading, ensuring that only fluorescently labeled sample compounds are introduced into the separation system. This preliminary action approach simplifies the overall analysis procedure by removing the destaining step entirely, reducing both procedural complexity and analysis time while maintaining high detection sensitivity.
Solution Approach 2:
The invention applies the extraction principle by removing the destaining step from the analysis workflow. Through covalent labeling before separation, the harmful background fluorescence is effectively extracted or eliminated from the system, as unlabeled dye molecules never enter the separation channel. This simplifies the device operation and reduces the number of required steps, making the analysis procedure more efficient and easier to perform.
3Measurement precision
If high conductivity background buffers are used to enhance stacking effects, then sample compound concentration increases and detection sensitivity improves, but electric current limitations are exceeded
Solution Approach 1:
The invention successfully applies parameter changes by optimizing the background buffer composition with high ionic strength and conductivity to maximize the stacking effect. By carefully adjusting buffer parameters such as salt concentration and pH, the system achieves effective sample concentration at the detection interface. The covalent labeling approach enables this high-conductivity buffer approach to work effectively, as the pre-labeled samples produce strong fluorescent signals that can be detected at lower currents, thereby resolving the current limitation issue.
Solution Approach 2:
The preliminary covalent labeling of sample compounds enhances the detection signal strength before separation begins. This preliminary action ensures that even when using high conductivity buffers that may generate elevated currents, the labeled samples produce sufficiently strong fluorescent signals for sensitive detection. The pre-labeling step compensates for any signal loss that might occur during high-current separation, allowing the system to operate at optimal buffering conditions without exceeding practical current limits.
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 approach significantly reduces background fluorescence, simplifies on-chip analysis, and enhances detection sensitivity by increasing the concentration of sample compounds through 'stacking' effects, allowing for higher electric currents and improved signal-to-noise ratios.
Implementation Method 1
the dye species having reactive groups adapted for forming covalent bonds with specific groups of the sample compounds
Implementation Method 2
providing the modified sample compounds to a microfluidic chip, the microfluidic chip being adapted to provide an electrophoretic separation
Implementation Method 3
By using a high conductivity background buffer is especially advantageous with regard to an effect called 'stacking'. Due to this effect, by using a background buffer of increased ionic strength, an increase of the respective concentrations of sample compounds is observed.
Data Source
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AI summary
A method for analyzing a sample comprising different sample compounds is described. The method comprises staining the sample compounds by adding a dye species to a solution of the sample, the dye species having reactive groups adapted for forming covalent bonds with specific groups of the sample compounds, and providing the modified sample compounds to a microfluidic chip, the microfluidic chip being adapted to provide an electrophoretic separation. The method further comprises electrophoretically separating the modified sample compounds, and detecting separated compounds.