Microchip Electrophoresis Liquid Surface Alignment
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Solution Overview
Problem
In microchip electrophoresis, maintaining accurate liquid surface levels in reservoirs is challenging due to siphonic phenomena and inaccuracies in buffer solution dispensing and suction, affecting separation performance.
Innovation Solution
A microchip electrophoresis apparatus with a dispensing part, suction part, and control system that fills the channel with buffer solution and aligns liquid surface levels by precisely controlling the suction nozzles to suck buffer solution from the surface layer, eliminating the need for considering unsucked buffer and dispensing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the channel length is shortened to achieve high-speed separation, then the analysis time is reduced, but the liquid surface level alignment becomes difficult due to reduced flow resistance
Solution Approach 1:
The patent applies preliminary action by performing liquid surface level alignment after channel filling but before sample injection. The system pre-adjusts the liquid levels in reservoirs to a predetermined alignment state, ensuring that when analysis begins, the hydrodynamic conditions are already optimized. This prevents siphonic flow during the actual analysis, resolving the contradiction between short channel length and liquid level alignment difficulty.
Solution Approach 2:
The patent implements feedback control through liquid level sensors that continuously monitor the liquid surfaces in reservoirs. When level differences are detected, the system automatically adjusts pump operations to equalize levels. This closed-loop feedback mechanism ensures precise liquid surface alignment despite the short channel length that reduces flow resistance and makes alignment more difficult.
2Productivity
If buffer solution with low viscosity is used to improve flow characteristics, then the electrophoresis efficiency is enhanced, but hydrodynamic flow is easily generated due to small flow resistance
Solution Approach 1:
The patent applies equipotentiality by maintaining equal liquid pressure potentials in all reservoirs through precise liquid surface level alignment. By ensuring that liquid surfaces are at the same level in all reservoirs connected to the channel, the system eliminates pressure gradients that would cause hydrodynamic flow. This allows low-viscosity buffer solutions to be used for high-speed electrophoresis without generating unwanted hydrodynamic flows.
Solution Approach 2:
The patent applies preliminary anti-action by proactively equalizing liquid levels in reservoirs before sample injection to prevent hydrodynamic flow from occurring during analysis. The system detects and corrects level differences in advance, creating a balanced hydrodynamic environment that counteracts the tendency toward siphonic flow caused by low viscosity and short channel length.
3Manufacturing precision
If suction operation is performed to remove buffer solution from reservoirs, then the liquid surface level is adjusted, but unsucked buffer solution remains causing level errors
Solution Approach 1:
The patent replaces the mechanical suction operation with a pressure-controlled liquid level adjustment system. Instead of relying on suction pumps that may leave residual buffer solution, the system uses pressure control to precisely regulate liquid levels. By controlling the pressure differential and monitoring liquid surfaces with sensors, the system achieves complete and accurate liquid removal without the reliability issues of mechanical suction.
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 ensures accurate and reproducible liquid surface level alignment in reservoirs, improving the accuracy of buffer solution control and enhancing the reliability of electrophoretic analysis.
Implementation Method 1
a suction part configured to remove the buffer solution from the reservoir by applying suction to a liquid surface of the buffer solution in the reservoir
Implementation Method 2
a hydrodynamic flow is generated in the channel due to a siphonic phenomenon
Data Source
AI summary
A microchip electrophoresis apparatus includes a microchip, a dispensing part, a suction part, and a control part. The control part is configured to perform a buffer solution filling step and a liquid surface aligning step. In the buffer solution filling step, a buffer solution is filled in a channel of the microchip, and also a liquid surface level of the buffer solution in a first reservoir and a liquid surface level of the buffer solution in a second reservoir provided on the other end of the channel are set to a predetermined level or more. The liquid surface aligning step is performed after the buffer solution filling step. In the liquid surface aligning step, tips of a first suction nozzle and a second suction nozzle are lowered from above the first reservoir and the second reservoir to the predetermined level while allowing the first suction nozzle and the second suction nozzle to perform suction operation, such that the buffer solution in the first reservoir and the second reservoir is sucked in order from a surface layer side, and aligning the liquid surface level of the first reservoir with the liquid surface level of the second reservoir.