Magnetic Particle Concentration for CD4+ T Cell Detection
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Solution Overview
Problem
Current methods for measuring CD4+ T cells in HIV-infected patients are complex and costly, requiring optical scanning of samples and multiple steps, which complicates the process and increases costs.
Innovation Solution
An optical instrument and method that uses a focusing magnet to concentrate analyte in a small detection region within a sample chamber, allowing for optical analysis without removing the sample fluid, reducing background signal and simplifying the process by using a homogeneous format with excitation and detection optics positioned opposite the magnet, enabling efficient detection of CD4+ T cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical scanning is used to detect and count CD4+ T cells, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the CD4+ T cells from the bulk sample fluid using magnetic separation. Magnetic particles conjugated to anti-CD4 antibodies selectively bind to CD4+ T cells, allowing them to be concentrated and isolated in a detection region while the rest of the sample fluid remains in the chamber. This extraction eliminates the need for complex optical scanning of the entire sample volume, simplifying the detection process while maintaining measurement accuracy.
2Measurement precision
If magnetic separation is used to concentrate analyte, then detection sensitivity is improved, but sample handling complexity increases
Solution Approach 1:
The patent merges the magnetic separation function with the detection chamber itself. The sample chamber serves dual purposes: as the reaction vessel for magnetic separation and as the detection region for optical analysis. Magnetic particles are concentrated at the side or bottom of the same chamber where detection occurs, eliminating the need for separate separation and detection chambers and the complex fluid handling required to transfer samples between them.
3Measurement precision
If sample fluid is removed after magnetic labeling, then background signal is reduced, but procedural steps increase
Solution Approach 1:
The patent maintains continuous presence of the sample fluid in the detection chamber throughout the assay process. After magnetic concentration of CD4+ T cells, the sample fluid remains in the chamber and is not removed. The detection system is designed to detect fluorescent signals from the magnetically concentrated cells while tolerating the presence of the sample fluid, thereby eliminating the additional procedural step of fluid removal while maintaining acceptable signal-to-noise ratios.
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 approach simplifies and cost-reduces the measurement of CD4+ T cells by eliminating the need for optical scanning and sample fluid removal, providing accurate and reliable quantitation of CD4+ T cells without interfering with the magnet's concentration process, enhancing the signal-to-noise ratio and reducing procedural complexity.
Implementation Method 1
a focusing magnet adapted to concentrate magnetic particles bound to an analyte into a small detection region within a sample chamber
Implementation Method 2
excitation optics adapted to illuminate the magnetically concentrated analyte and detection optics adapted to measure light emitted from the magnetically concentrated analyte
Data Source
AI summary
The present invention proves instruments and methods for detecting and/or quantitating an analyte in a fluid sample. The fluid sample is placed in a sample chamber having a small, shallow detection region. The analyte is magnetically labeled using magnetic particles coated with a binding reagent, and is detectably labeled using a fluorescent dye or other detection reagent. The magnetically labeled analyte is concentrated into the detection region using a focusing magnet positioned underneath the sample chamber detection region. Concentrated analyte is measured using excitation optics positioned on top of the sample chamber detection region, adapted to illuminate only the detection region, and detection optics positioned on top of the detection region, adapted to detect only light emitted from the detection region. In a preferred embodiment, the invention provides a simple, rapid assay for measuring the concentration of CD4+T cells in a whole blood sample.