Multivolume Microfluidic Chip for Viral Load Quantification
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Solution Overview
Problem
Current methods for monitoring viral load, such as real-time quantitative RT-PCR, are cost-prohibitive and require skilled technicians and specialized equipment, making them inaccessible in resource-limited settings, and lack a quantitative test to detect clinically significant changes in HIV RNA viral load.
Innovation Solution
A microfluidic device with multiple analysis regions of varying volumes that allows for the distribution and amplification of target molecules, enabling quantitative measurement and detection of viral load through multivolume digital RT-PCR, which reduces the need for complex control systems and can be operated manually.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time quantitative RT-PCR is used to monitor viral load, then measurement precision is improved, but device complexity and cost increase, making it inaccessible in resource-limited settings
Solution Approach 1:
The device divides the sample analysis into multiple discrete reaction areas with different volumes (e.g., 1 nL, 5 nL, 10 nL, 20 nL) on a single chip. Each area independently processes aliquots of the same sample, enabling quantitative measurement through statistical analysis of positive/negative results across volumes without requiring complex real-time PCR instrumentation.
Solution Approach 2:
The invention uses a disposable microfluidic chip that can be manufactured at low cost using standard microfabrication techniques. The chip contains pre-formed reaction areas and is intended for single-use, eliminating the need for expensive, complex, and reusable PCR instruments while maintaining measurement precision.
2Measurement precision
If real-time quantitative RT-PCR is used, then measurement precision is improved, but ease of operation deteriorates due to requirement for skilled technicians
Solution Approach 1:
The device incorporates pre-formed reaction areas with defined volumes and pre-loaded reagents within the microfluidic chip. The user simply needs to load the sample and follow simple instructions; the system automatically distributes sample aliquots to different volumes and performs the reactions, eliminating the need for skilled technicians to perform complex pipetting and reaction setup.
3Measurement precision
If multiple instruments and isolated rooms are used for RT-PCR, then measurement precision is improved, but device complexity worsens
Solution Approach 1:
The invention integrates multiple reaction volumes, reagent storage, sample processing, and detection capabilities into a single microfluidic chip. This consolidation eliminates the need for multiple separate instruments (pipettes, thermal cyclers, centrifuges) and specialized facility requirements, while maintaining the ability to perform accurate quantitative RT-PCR through the multivolume statistical approach.
4Ease of operation
If dipstick-type devices are used for semiquantitative measurements, then ease of operation is improved, but measurement precision deteriorates by inability to detect 3-fold changes in viral load
Solution Approach 1:
The device creates reaction areas with locally different volumes (1 nL, 5 nL, 10 nL, 20 nL) on the same chip, each optimized for detecting different concentration ranges. This local variation in volume allows the system to resolve small changes in viral load (3-fold changes) by comparing positive/negative results across the volume gradient, while maintaining operational simplicity suitable for resource-limited settings.
Data Source
AI summary
Provided are devices comprising multivolume analysis regions, the devices being capable of supporting amplification, detection, and other processes. Also provided are related methods of detecting or estimating the presence nucleic acids, viral levels, and other biological markers of interest.