One-Step Sample Extraction Cassette With Moving Membrane
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Solution Overview
Problem
Current COVID-19 testing methods are time-consuming, laborious, and difficult to scale, requiring multiple steps and specialized equipment, leading to prolonged turnaround times and logistical challenges for point-of-care molecular testing.
Innovation Solution
A one-step sample extraction cassette for point-of-care molecular testing, featuring a chamber, wash zone, and reaction zone with a membrane that moves between positions to facilitate sample transfer, wash, and reaction, using hydrophobic and hydrophilic materials to isolate fluids and reduce reagent consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-step column-based or magnetic bead-based RNA extraction methods are used, then extraction purity and completeness are improved, but test turnaround time increases and operational complexity increases
Solution Approach 1:
The patent combines multiple separate extraction steps (lysis, binding, washing, elution) into a single integrated membrane-based operation. The membrane simultaneously performs sample loading, RNA binding, and enables sequential washing and elution through fluid flow control, reducing the process from multiple discrete steps to one unified operation that maintains extraction purity while dramatically reducing time.
Solution Approach 2:
The extraction membrane serves multiple functions simultaneously: it acts as a binding matrix for RNA, a filter for sample filtration, a barrier for contamination, and a conduit for fluid flow control. This multi-functionality eliminates the need for separate components for each extraction step, reducing operational complexity and time while maintaining extraction effectiveness.
2Measurement precision
If multiple pipetting and centrifugation/magnetic separation steps are performed for washing, then extraction completeness is improved, but device complexity and operational difficulty increase
Solution Approach 1:
The patent extracts and eliminates the need for complex mechanical operations (centrifugation, magnetic separation, multiple pipetting steps) by using a membrane-based system where washing and elution are achieved through controlled fluid flow. The membrane structure itself performs the separation function that previously required complex mechanical devices, dramatically simplifying the system while maintaining extraction completeness.
Solution Approach 2:
The patent replaces mechanical separation systems (centrifuges, magnetic separators) with a membrane-based filtration and flow control system. The membrane's physical structure and fluid dynamics enable washing and elution without requiring mechanical force, reducing device complexity and operational difficulty while maintaining extraction effectiveness.
3Measurement precision
If standardized RT-qPCR protocols are used, then detection accuracy is improved, but cost and reagent consumption increase
Solution Approach 1:
The patent applies local quality optimization by using a membrane with specific local properties (hydrophilic surface for RNA binding, controlled porosity for flow, selective permeability for molecule size separation). This localized functional optimization enables effective extraction with reduced reagent quantities, as the membrane structure itself performs the extraction function that would otherwise require excess reagents, maintaining detection accuracy while reducing consumption.
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
The cassette significantly reduces turnaround time, simplifies the testing process, and decreases costs by integrating multiple steps into a single device, making it suitable for point-of-care settings.
Implementation Method 1
The case is defined by a plurality of surfaces. The plurality of surfaces are hydrophobic. The contact portion of the membrane is defined by a hydrophilic adsorbent pad.
Implementation Method 2
The contact portion of the membrane is defined by a hydrophilic adsorbent pad.
Implementation Method 3
A membrane having a contact portion is slidably receivable into case. The membrane is moveable between a transfer position, a wash position and a reaction position.
Data Source
AI summary
A sample extraction cassette and method are provided to test for a target in a sample. The sample is obtained on a swab. The swab is inserted into a chamber in a case and into contact with a contact portion of a membrane. The contact portion of the membrane is axially moved into sequential communication with a wash fluid and a reaction fluid. The reaction fluid reacts with the target to provide a visual display corresponding to the presence of the target.