Electrospun Nanofiber Membranes for Consistent Lateral Flow
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Solution Overview
Problem
Conventional methods for producing membranes for lateral flow diagnostic devices, such as air-casting and phase inversion, are complex, slow, and sensitive to environmental conditions, leading to inconsistent pore sizes and thicknesses, and nitrocellulose membranes face handling issues like brittleness and delamination.
Innovation Solution
The use of electrospun non-woven fiber membranes with nanofibers having an average diameter between 200 nm to 1000 nm and porosities of 80% to 90%, produced by electrospinning or electroblowing polymers like PMMA and PVDF, which provide consistent capillary flow, detector bead mobility, and high protein binding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If air-casting method is used to produce nitrocellulose membranes, then porosity and mean flow pore diameter are improved, but manufacturing complexity and production time increase
Solution Approach 1:
The patent replaces the complex mechanical air-casting process with a simpler electrospinning process that uses electrical fields to form nanofibers. This substitution eliminates the need for complex solvent evaporation control, humidity management, and large-scale expensive equipment while achieving consistent pore sizes and high porosity through controlled fiber deposition.
Solution Approach 2:
The patent changes the fundamental parameters of the manufacturing process by transitioning from solvent-based air-casting to electrospinning using polymer solutions or melts. This parameter change enables production at higher line speeds with consistent quality, as the electrospinning process is less sensitive to environmental conditions like temperature and humidity that plague conventional air-casting.
2Manufacturing precision
If air-casting method is used, then porosity is improved, but production speed decreases
Solution Approach 1:
The patent replaces the slow mechanical air-casting process with electrospinning, which can operate at significantly higher line speeds. The electrospinning process forms nanofibers rapidly through electrical forces, enabling continuous production without the slow solvent evaporation step required in air-casting, thus achieving both high porosity consistency and high productivity.
3Stability of the object's composition
If nitrocellulose membranes are cast onto non-porous films, then handling stability is improved, but flexibility and durability worsen due to brittleness and delamination
Solution Approach 1:
The patent uses flexible non-woven nanofiber mats as the membrane structure itself, eliminating the need for rigid non-porous film supports. The nanofiber network inherently provides both stability and flexibility, allowing the membrane to be handled without brittleness or delamination issues while maintaining consistent porosity and flow characteristics.
Solution Approach 2:
The patent creates a composite structure where nanofibers are collected on a temporary support film that can be easily removed, or directly forms a self-supporting mat. This composite approach during manufacturing enables production stability, while the final product achieves handling ease through the flexible nanofiber network without requiring rigid film substrates.
4Manufacturing precision
If conventional membrane methods are used, then protein binding capacity is achieved, but flow rate and detector particle mobility are limited due to pore size constraints
Solution Approach 1:
The patent applies local quality by creating a hierarchical pore structure within the nanofiber mat, where the nanofiber diameter (200-1000 nm) creates interstitial pores that are optimally sized for both protein binding and detector particle mobility. This local structural optimization allows simultaneous achievement of high protein binding capacity and fast capillary flow rates with excellent bead mobility.
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 electrospun membranes offer improved consistency, flexibility, and durability, enabling faster capillary flow and effective detector bead mobility, while maintaining high protein binding capacity, addressing the limitations of traditional methods.
Implementation Method 1
electrospinning or electroblowing polymers like PMMA and PVDF
Implementation Method 2
aqueous media and nanoparticles (e.g., gold or latex beads) pass by capillary flow
Data Source
Figure 1
Figure 2
Figure 3.1~3.2
AI summary
Provided herein are electrospun or electroblown non-woven fiber membranes, methods of making such membranes and lateral flow diagnostic devices comprising such membranes.