Isothermal Nucleic Acid Assay Card With Electricity-Free Heating
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Solution Overview
Problem
Conventional nucleic acid testing methods require complex laboratory equipment, cold storage, and skilled personnel, limiting their accessibility and cost-effectiveness for point-of-care and remote diagnostics.
Innovation Solution
A portable assay device with a simple mechanical design and electricity-free heating configuration that performs isothermal nucleic acid amplification and detection using a reaction card with laminate construction, passive microfluidics, and a readout indicator, eliminating the need for specialized equipment and trained personnel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laboratory-based PCR assays are used, then nucleic acid amplification and detection can be achieved, but the device complexity, cost, and requirement for specialized equipment and trained personnel increase
Solution Approach 1:
The patent employs disposable reaction cards with integrated reagents that are lyophilized (freeze-dried) for stable storage at room temperature. Each reaction card contains pre-aliquoted reagents including master mix, blocking agents, and readout indicators, eliminating the need for cold storage and complex laboratory equipment while maintaining reliable nucleic acid amplification and detection
Solution Approach 2:
The reaction card integrates multiple functions into a single device: sample reception, reagent storage, thermal reaction chamber, and visual readout. The master mix, blocking agents, and readout indicators are combined in predetermined ratios within the reaction card, simplifying the overall system while ensuring reliable assay performance
2Stability of the object's composition
If cold storage and cold chain transport are used for reagents, then reagent stability is maintained, but the overall complexity and cost of the assay increase
Solution Approach 1:
The patent utilizes lyophilization (freeze-drying) to convert liquid reagents into a stable solid state that can be stored at room temperature. The master mix and other reagents are lyophilized within the reaction card, eliminating the need for cold storage while maintaining reagent stability. Water is added during the assay procedure to reconstitute the reagents
Solution Approach 2:
Reagents are pre-aliquoted and lyophilized in the reaction card before use, with precise concentrations and ratios established during manufacturing. This preliminary preparation ensures reagent stability and eliminates the need for cold storage, while also simplifying the user操作流程 by requiring only the addition of water and sample
3Reliability
If dedicated pre-processing steps are performed for sample inactivation, lysis, and nucleic acid extraction, then sample quality is improved for amplification, but the number of processing steps and complexity increase
Solution Approach 1:
The reaction card integrates sample processing and nucleic acid amplification into a single unified system. The master mix contains enzymes and reagents that perform sample lysis, nucleic acid extraction, and amplification simultaneously in the same reaction chamber, eliminating the need for separate pre-processing steps while maintaining reliable sample quality for detection
Solution Approach 2:
The master mix formulation is designed to be universally compatible with various sample types and performs multiple functions: sample lysis, nuclease inhibition, nucleic acid extraction, and isothermal amplification. This multi-functional approach simplifies the workflow while ensuring reliable amplification results
4Ease of operation
If isothermal amplification techniques are used, then the assay is more tolerant to inhibitors and simpler than PCR, but the performance still depends on sample quality requiring pre-processing
Solution Approach 1:
The reaction card combines sample processing and isothermal amplification in a single integrated system. The master mix contains all necessary components for sample lysis, nucleic acid extraction, and amplification, eliminating the need for separate pre-processing steps while maintaining the simplicity and inhibitor tolerance of isothermal amplification
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
Enables rapid, accurate, and cost-effective nucleic acid testing at the point of care or remote locations without electricity, reducing complexity and cost while maintaining assay performance.
Implementation Method 1
A temperature regulator may be disposed between the heat source and the reaction card. The temperature regulator may comprise a phase change material, such as one or more solvents, with a boiling point that is at or above a target reaction temperature for the reaction card.
Implementation Method 2
The assay device may further comprise a heat source and a temperature regulator disposed between the heat source and the reaction card. The heat source may be configured to generate heat through an exothermic reaction.
Data Source
AI summary
Disclosed is an assay device for isothermal amplification and detection of one or more target nucleic acids. The assay device can utilize a simple mechanical design, an effective reagent chemistry, and an electricity-free heating configuration that enable a low-cost, highly accessible assay device. The assay device can be utilized in the field and/or in point-of-care (POC) applications without the need for sophisticated laboratory equipment, without the need for electricity or batteries, and without significantly sacrificing assay performance relative to conventional, higher-cost laboratory approaches.