Microfluidic Biological Sample Analysis With Pressure Differentials
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Solution Overview
Problem
Transport and ionization of large biological molecules for mass spectroscopic analysis pose challenges due to their fragility and the need for precise control over fluidic environments, which conventional electroosmotic pumping systems struggle to achieve.
Innovation Solution
The use of pressure differentials in microfluidic chips decouples the flow rate from the applied potential difference, allowing independent control over sample component separation and analysis, using gas pressure to drive fluid flow through channels without modifying the surface chemistry of the channel walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electroosmotic pumping is used to transport biological samples through fluidic channels, then sample flow can be achieved, but the flow rate is coupled to the applied potential difference which limits independent control over separation and analysis parameters
Solution Approach 1:
The system divides the fluidic transport function from the electrophoretic separation function. Pressure differentials are applied to the bulk fluid through pumping channels to control flow rate, while electrical potentials are applied specifically to the separation channel to control electrophoretic mobility. This segmentation allows independent optimization of both parameters.
Solution Approach 2:
A pressure-driven flow system acts as an intermediary mechanism to transport the sample through the separation channel without directly coupling the flow rate to the electrical potential. The pressure differential serves as a mediator that decouples the hydrodynamic flow from the electrophoretic separation, enabling independent control.
2Reliability
If conventional electroosmotic pumping systems are used, then sample transport is achieved, but precise control over fluidic environment for fragile biological molecules is difficult
Solution Approach 1:
The system replaces electroosmotic pumping (which relies on electrical fields interacting with charged channel walls) with a pressure-driven mechanical pumping system. This substitution provides more direct and precise control over fluidic parameters, creating a more stable and controllable environment for fragile biological molecules.
3Adaptability or versatility
If pressure differentials are applied to drive fluid flow, then flow rate can be controlled independently of applied potential difference, but additional pressure control mechanisms are required
Solution Approach 1:
The pressure control system serves multiple functions: it drives fluid flow through the separation channel, controls the flow rate independently of electrical potentials, and can be adjusted to optimize both separation efficiency and analysis conditions. This multi-functionality justifies the added complexity by providing versatile control capabilities.
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 enables precise control over sample separation and analysis, facilitating efficient and reproducible mass spectrometry by decoupling electroosmotic flow from electrophoretic mobility, thus improving the accuracy and adaptability of biological sample handling systems.
Implementation Method 1
The use of pressure differentials allows for the transport of sample components through flow channels under applied potential differences that would otherwise be too small to effect component transport in the absence of the pressure differentials.
Implementation Method 2
applying an electrical potential difference across the sample to cause migration of at least one sample component toward an end of the separation channel
Implementation Method 3
adjusting at least one of a gas pressure in a reservoir comprising a second electrolyte solution, and a gas pressure external to an aperture positioned at the end of the separation channel, so that the gas pressure in the reservoir is greater than the gas pressure external to the aperture
Data Source
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AI summary
The disclosure features methods and systems for processing samples that include introducing a sample (360) featuring one or more components in a first electrolyte solution (312) into a separation channel (304) of a fluidic device (300), using electrodes (316,318) for applying an electrical potential difference across the sample to cause migration of at least one sample component toward an end (320) of the separation channel (304), and adjusting at least one of a gas pressure in a reservoir (306) comprising a second electrolyte solution (314), and a gas pressure external to an aperture positioned at the end of the separation channel, so that the gas pressure in the reservoir (306) is greater than the gas pressure external to the aperture, and directing a flow of the second electrolyte solution (314) in response to the gas pressures through the pumping channel (308) and out of the aperture (310) to discharge the at least one sample component including background electrolyte solutions from separation channel and pumping channel (340) through the aperture (310).