Reaction Processor Air Communication Ports PCR Contamination
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Solution Overview
Problem
PCR is sensitive to contaminants, leading to carryover issues where products from previous reactions can affect subsequent reactions, causing misinterpretation even with small contamination levels.
Innovation Solution
A reaction processor with a channel and air communication ports, a temperature control system, and a liquid feeding system that alternately discharges and sucks air to move and stop samples within the channel, using filters and controlled temperature regions to prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PCR is performed with high sensitivity to detect minute amounts of DNA, then detection capability is improved, but carryover from previous reactions occurs causing misinterpretation
Solution Approach 1:
The reaction processing vessel is divided into multiple temperature regions (first temperature region for denaturation, second temperature region for annealing/extension, and third temperature region for product deposition). This spatial segmentation allows different stages of PCR to occur in separate zones, preventing carryover by physically isolating amplified products from the reaction mixture during critical phases.
Solution Approach 2:
A filter is introduced as an intermediary component between the reaction processing vessel and the external environment. The filter allows gases to pass through while blocking aerosolized DNA fragments, thereby preventing carryover contamination while maintaining the sensitivity needed for detecting minute amounts of DNA.
2Ease of operation
If air communication ports are provided for liquid feeding, then sample movement control is improved, but aerosolized DNA fragments can escape and cause contamination
Solution Approach 1:
The filter serves as an intermediary component installed in the air communication port. It selectively allows gas molecules to pass through while blocking larger aerosolized DNA fragments, thus maintaining ease of operation for sample movement control while preventing contamination from escaping aerosols.
Solution Approach 2:
The air communication port is given local quality through the filter installation. The filter creates a selective permeability at this specific location, allowing free gas exchange while blocking contaminants, thus resolving the contradiction between operational ease and contamination prevention.
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
Effectively prevents or suppresses carryover, allowing for accurate PCR results even with low initial specimen concentrations by minimizing the introduction of aerosolized DNA fragments into the reaction system.
Implementation Method 1
a temperature control system that provides a first temperature region maintained at a first temperature and a second temperature region maintained at a second temperature higher than the first temperature between the pair of air communication port in the channel
Implementation Method 2
a liquid feeding system that discharges and sucks air in order to move and stop the sample inside the channel
Data Source
AI summary
A reaction processor includes: a reaction processing vessel including a channel in which a sample moves and a pair of air communication ports, a first air communication port and a second air communication port, provided at respective ends of the channel; a temperature control system that provides a medium temperature region and a high temperature region between the first air communication port and the second air communication port in the channel; and a liquid feeding system that discharges and sucks air in order to move and stop the sample inside the channel. One of the pair of air communication ports of the reaction processing vessel that is farther away from the high temperature region communicates with the liquid feeding system via a tube. One of the pair of air communication ports of the reaction processing vessel that is closer to the high temperature region is opened to atmospheric pressure.