Flow Virometer Detects Viruses via Hydrodynamic Focusing
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Solution Overview
Problem
Current viral detection methods, such as PCR, are laborious, resource-intensive, and prone to false positive results due to the need for multiple amplification cycles, which can lead to delayed diagnosis and inefficient use of resources.
Innovation Solution
A microfluidic device employing inverse fluorescence cross-correlation spectroscopy (iFCCS) with hydrodynamic focusing to rapidly and accurately detect intact virus particles at low concentrations by using two fluorescent dyes and antibodies specific to viral surface proteins, enabling specific and sensitive detection within minutes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PCR amplification cycles are increased to detect low viral loads, then detection sensitivity is improved, but detection time and false positive rate increase
Solution Approach 1:
The patent replaces the mechanical/chemical amplification process of PCR with a direct optical detection system using flow cytometry. Instead of amplifying viral genetic material through thermal cycling, the system directly detects intact viral particles using fluorescent dyes and optical detectors, eliminating the time-consuming amplification steps while maintaining detection sensitivity.
Solution Approach 2:
The patent extracts and detects intact viral particles directly from the sample without requiring amplification. By using fluorescent dyes that bind to viral surface proteins and flow cytometry to detect these particles directly, the system removes the unnecessary amplification step while maintaining the ability to detect low viral loads.
2Measurement precision
If PCR amplification cycles are increased to detect low viral loads, then detection sensitivity is improved, but false positive rate increases
Solution Approach 1:
The patent replaces PCR's indirect nucleic acid detection with direct optical detection of intact viral particles. By using fluorescent dyes that specifically bind to viral surface proteins and detecting the particles themselves rather than amplified genetic copies, the system eliminates false positives that arise from non-specific amplification while maintaining sensitivity for low viral loads.
Solution Approach 2:
The patent extracts and detects intact viral particles directly, removing the amplification step that causes false positives. By detecting the actual viral particles through their optical properties and specific protein binding, the system achieves both sensitivity and reliability without the false positive issues of multi-cycle PCR.
3Device complexity
If conventional fluorescence-based detection is used for intact viruses, then detection simplicity is maintained, but detection accuracy and sensitivity are reduced due to low particle concentration
Solution Approach 1:
The patent uses fluorescent dyes as intermediaries that bind specifically to viral surface proteins. These dyes act as mediators between the viral particles and the detection system, amplifying the signal without requiring the viruses themselves to be directly visible. The dyes concentrate the detection signal on the viral particles, enabling accurate detection even at low concentrations.
Solution Approach 2:
The patent employs flow cytometry principles to hydraulically focus and transport viral particles through a detection zone. By using fluid dynamics to concentrate particles in a controlled flow pattern, the system increases the effective concentration of targets in the detection region, enabling accurate fluorescence-based detection despite low overall particle concentration in the sample.
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 method allows for the detection of at least 100 virus particles in less than 10 minutes at concentrations as low as 10^3 particles/mL, reducing false positives and negatives, and is adaptable for various viruses and biological samples.
Implementation Method 1
A microfluidic device employing inverse fluorescence cross-correlation spectroscopy (iFCCS) with hydrodynamic focusing to rapidly and accurately detect intact virus particles
Implementation Method 2
inverse fluorescence cross-correlation spectroscopy (iFCCS) with hydrodynamic focusing to rapidly and accurately detect intact virus particles
Implementation Method 3
inverse fluorescence cross-correlation spectroscopy (iFCCS)
Implementation Method 4
using two fluorescent dyes and antibodies specific to viral surface proteins
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 2D~2G
AI summary
Systems and methods that allow optical detection of nanoparticles according to size and interaction with specific antibodies. Using a biological sample combined with fluorescent dyes and fluorescently labeled antibodies, implementations of the disclosed system allow for detection of >100 particles having diameters as low as 100 nm in under 10 minutes. The detection mechanisms combine confocal detection of particles in microfluidic flow devices. Concentrating the sample using hydrodynamic focusing allows detection of particles having concentrations as low as 104 particles per mL of the sample. These capabilities allow for the detection, identification, and quantitation of viruses from bodily fluids such as saliva, where biologically relevant virus concentrations of potentially infected subjects are within the range of 103-107 particles/mL. The system and methods comprise a 'flow virometer' providing rapid, direct feedback regarding the existence of specific viruses in a biological sample and serves as a technological basis for commercial products.