Lateral to Free Flow Assay Device for TIR Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lateral flow immunoassay devices using wicking membranes are not suited for Total Internal Reflection (TIR) illumination due to high scatter, which interferes with detection methods, and require expensive equipment and skilled personnel, while existing enzyme-linked immunosorbent assays (ELISA) have long processing times.
Innovation Solution
A lateral to free flow assay device that incorporates a wicking pad for sample collection and filtration, combined with an optical element configured for TIR, allowing for efficient fluid flow and analysis, and potentially using surfactants or proteins to enhance flow properties and reduce scatter, enabling sensitive read-outs through TIR or TIRF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wicking membrane is used in lateral flow immunoassay devices, then excellent protein binding and low background are achieved, but high scatter is produced that interferes with TIR illumination and detection methods
Solution Approach 1:
The device is divided into two distinct functional sections: a lateral flow section with wicking membrane for sample application and a free flow section for TIR analysis. This segmentation allows each section to optimize its function without interference - the wicking membrane provides excellent protein binding while the free flow region eliminates scatter for TIR illumination.
Solution Approach 2:
The wicking membrane is extracted from the TIR analysis region and placed only in the lateral flow section. This removal eliminates the scatter problem in the detection region while preserving the protein binding capabilities of the wicking membrane in the sample application region.
2Measurement precision
If ELISA assays are used to analyse saliva samples, then quantification of biomarkers is achieved, but expensive equipment and skilled personnel are required along with long processing time
Solution Approach 1:
The complex mechanical and automated systems required for ELISA (plate readers, washers, incubators) are replaced with a simplified lateral flow device using TIR illumination. The assay transitions from a multi-step mechanical process to a passive capillary flow system with optical detection, eliminating the need for expensive equipment and reducing processing time to minutes.
3Measurement precision
If a lateral flow device is designed for TIR illumination, then ultra-sensitive read-out is achieved, but the wicking pad creates scatter that reaches the detector despite light filtering
Solution Approach 1:
The device is segmented into a lateral flow section containing the wicking pad and a separate free flow section for TIR analysis. This physical separation ensures that scatter generated in the lateral flow section cannot reach the detector in the free flow section, preserving the ultra-sensitive read-out capability of TIR illumination.
Solution Approach 2:
The fluid pathway acts as an intermediary that transports sample from the lateral flow section to the free flow section. This intermediary pathway allows sample transfer while preventing the wicking pad scatter from reaching the detection region, enabling both functions to coexist.
4Ease of operation
If a disposable cartridge is used for sample collection at point of care, then intuitive use by unskilled operatives is achieved, but the device requires internal transport of sample to analysis region and subsequent placement in reading device
Solution Approach 1:
The lateral flow device is merged with the TIR analysis platform in a single integrated cartridge. The free flow region is designed to be directly compatible with the TIR reader, eliminating the need for separate positioning steps. Sample collection, processing, and analysis are combined in one device that can be used intuitively at point of care.
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 device provides a cost-effective, intuitive, and rapid analysis method for fluid samples, capable of achieving ultra-sensitive read-outs in minutes, contrasting with the hours required by ELISA assays, while minimizing scatter and improving detection accuracy.
Implementation Method 1
an optical element configured to facilitate TIR for the analysis of the sample
Implementation Method 2
a wicking pad defining a lateral flow section of the fluid pathway or provided in the sample collection unit to collect the sample
Data Source
AI summary
A lateral to free flow assay device is provided for analysis of a fluid sample. The device comprises: a sample collection unit configured to introduce the sample into the device; an optical element configured to facilitate TIR for the analysis of the sample; a fluid pathway configured to provide fluid communication between the sample collection unit and a free flow region adjacent the optical element; a wicking pad defining a lateral flow section of the fluid pathway or provided in the sample collection unit to collect the sample; wherein at least one surface of the optical element defines at least part of the free flow region of the fluid pathway; and wherein the fluid pathway is configured to enable fluid flow from the lateral flow region to the free flow region of the fluid pathway to facilitate the analysis of the sample.