Serpentine Microfluidic Channel Segmented Flow PCR
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Solution Overview
Problem
Current PCR methods are slow due to thermal cycling limitations, leading to inefficient nucleic acid amplification, and existing continuous-flow systems face issues with air bubble formation and fluid resistance, hindering rapid temperature control and amplification.
Innovation Solution
The method employs segmented flow of a sample solution in a serpentine channel, utilizing vapor pressure differences to control temperature and reduce pressure loss, allowing for high-speed internal convection and efficient annealing, with the sample solution moving slowly in the heating direction and quickly in the cooling direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous flow of sample solution is used to fill the entire micro-flow channel, then the PCR reaction can proceed, but air bubbles are easily formed at the heating zone causing flow disturbance and stopping
Solution Approach 1:
The patent divides the continuous sample solution flow into discrete segmented flow units separated by gas bubbles. Each segment contains a portion of the sample solution and is separated from adjacent segments by gas phases. This segmentation prevents air bubble formation at heating zones while maintaining continuous flow operation, thereby resolving the contradiction between productivity and reliability.
2Loss of time
If the sample solution is moved quickly through temperature zones, then the PCR procedure time is reduced, but the thermal capacity of the heater cannot be reduced sufficiently
Solution Approach 1:
The patent transitions from temporal thermal cycling (heating and cooling over time at a fixed position) to spatial thermal cycling (moving the sample through spatially distributed temperature zones). The serpentine channel is designed with heating zones positioned at specific locations, allowing the sample to experience temperature changes by moving through space rather than waiting for thermal cycling over time. This dimensional change enables rapid temperature transitions while maintaining effective heater thermal capacity.
3Measurement precision
If segmented flow is used with vapor pressure differences, then temperature control is improved and pressure loss is reduced, but the system requires precise flow channel design
Solution Approach 1:
The patent utilizes vapor pressure differences that arise from temperature variations along the serpentine channel to drive the segmented flow. By designing the flow channel with appropriate dimensions and heating zones positioned at specific locations, the system harnesses natural vapor pressure gradients to control flow velocity and residence time in different temperature zones. This parameter-based control achieves precise temperature management while avoiding complex mechanical actuation systems.
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 ultra-rapid nucleic acid amplification by accurately controlling temperature and minimizing by-product extension, achieving high-speed and efficient PCR without additional external devices, while minimizing sample volume and optimizing microfluidic device advantages.
Implementation Method 1
utilizing vapor pressure differences to control temperature and reduce pressure loss
Implementation Method 2
accelerating annealing by using high-speed internal convection of the sample solution
Data Source
AI summary
The invention provides an ultra-rapid nucleic acid amplification method performed in a flow channel. Specifically, the invention provides a nucleic acid amplification method for performing a PCR reaction by supplying a PCR sample solution to a nucleic acid amplification device comprising a serpentine channel adapted to perform at least one PCR cycle, the nucleic acid amplification device comprising a DNA denaturation temperature zone corresponding to the curved portions at one side, an annealing temperature zone corresponding to the curved portions at the other side, and an extension temperature zone positioned between the annealing and DNA denaturation temperature zones, wherein the PCR sample solution is introduced in the form of sample plugs separated by gas into the serpentine channel using a pump, the sample solution being supplied into the channel in a state such that the solution is separated by gas into a segment corresponding to one PCR cycle or smaller segments.