NMR Apparatus Surface Relaxivity Antigen Detection
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Solution Overview
Problem
Current NMR methods for detecting antigens in small liquid samples are limited by long incubation times and the need for complex enzyme-linked immunosorbent assays, which are not suitable for rapid quantitative analysis or differentiation of fluid properties near surfaces.
Innovation Solution
The use of NMR apparatus configured to measure T2 relaxation times in real-time, with specialized RF pulse sequences like CPMG, to differentiate between bulk and surface fluid properties, enabling rapid detection of antigens by altering surface relaxivity through antibody binding and nanoparticle conjugation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ELISA methods are used to detect antigens in small liquid samples, then detection sensitivity can be achieved, but incubation times are long and the procedure is complex
Solution Approach 1:
The patent replaces the enzymatic chemical reaction system of conventional ELISA with a nuclear magnetic resonance detection system. By using NMR to directly detect the presence and concentration of antigens through their magnetic properties, the method eliminates the need for multiple enzymatic incubation steps while maintaining detection sensitivity, thereby significantly reducing total assay time
Solution Approach 2:
The patent changes the detection parameter from optical signal measurement (color change in ELISA) to magnetic resonance signal measurement. By measuring NMR relaxation times and signal intensities of hydrogen nuclei in the liquid sample, the system achieves rapid antigen detection without requiring the time-consuming enzymatic amplification steps of ELISA
2Adaptability or versatility
If conventional NMR methods are used for antigen detection, then detection capability is provided, but the methods cannot differentiate between bulk and surface fluid properties
Solution Approach 1:
The patent segments the NMR signal into two distinct components: bulk signals from the interior of the liquid sample and surface signals from the liquid-gas interface. By separately measuring and analyzing these two signal components with different relaxation characteristics, the system retrieves information about both bulk and surface fluid properties that would be lost in conventional bulk-only NMR methods
Solution Approach 2:
The patent adds a spatial dimension to NMR detection by specifically probing the surface region of the liquid sample. Using surface coil geometry and optimized pulse sequences, the method detects NMR signals preferentially from molecules near the surface, creating a surface-sensitive detection mode that complements bulk detection and enables differentiation of surface-specific fluid properties
3Quantity of substance
If small liquid sample volumes are used for NMR detection, then sample consumption is reduced, but signal intensity decreases
Solution Approach 1:
The patent transitions from bulk-volume signal detection to surface-area signal detection by using a surface coil geometry. This allows the NMR signal to be generated preferentially from molecules at the liquid-gas interface rather than requiring a large bulk volume, enabling sensitive detection in microliter-scale samples where surface-to-volume ratio is high
Solution Approach 2:
The patent enhances the local magnetic field sensitivity at the liquid surface by using a surface coil positioned close to the sample. This creates a localized detection zone with high magnetic field strength and gradient near the surface, concentrating the NMR signal from a small volume of liquid and compensating for the reduced total number of nuclei available for detection
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 allows for rapid and sensitive detection of antigens, reducing incubation times and improving the sensitivity of NMR measurements by selectively measuring surface and bulk relaxivity, facilitating quicker analysis and diagnosis.
Implementation Method 1
Once generated, the magnitude of the NMR signal decays according to transverse (T2) and longitudinal (T1) relaxation properties of the water-containing material being analyzed. Spin-spin (T2) relaxation occurs when a given ensemble of oscillating hydrogen nuclear axis spins lose coherence.
Implementation Method 2
NMR signals as used methods according to the present disclosure arise from the nuclei of hydrogen atoms in water molecules.
Implementation Method 3
T2 relaxation can be measured independently from T2* by means of a specialized series of RF pulses and delays, called a CPMG (Can Purcell Meiboom Gill) pulse sequence. A CPMG pulse sequence removes the effects of macroscopic static magnetic field inhomogeneities to specifically measure the contribution from the microscopic environment, by creating a series of spin echoes.
Implementation Method 4
The relaxation time is significantly shorter for a molecule proximate a sample chamber surface or wall area, as compared to a molecule in the bulk volume. This is an effect of paramagnetic centers at a wall surface that causes the relaxation time to be faster.
Data Source
AI summary
A nuclear magnetic resonance (NMR) apparatus includes at least one magnet arranged to induce a static magnetic field in a sample chamber. The static magnetic field has a known amplitude distribution. At least one radio frequency antenna is configured to induce a radio frequency magnetic field in the sample chamber at a predetermined frequency and a predetermines bandwidth. The static magnetic field amplitude at a sample chamber boundary has substantially at most two values.