Biosensor Magnet Assembly Gap for Single Particle Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current biosensor systems face limitations in detecting single particles due to optical baseline drift and non-specifically bound beads, which restrict their sensitivity and resolution, especially in the sub-pM regime, with a minimum detectable concentration of 200 fM being an order of magnitude lower than the theoretical limit.
Innovation Solution
A biosensor system with a magnet assembly and dual optical detection systems, where the first system detects particles through a gap between magnetic subunits and the second system uses scattered light for enhanced detection, allowing for simultaneous magnetic actuation and optical detection without interference, enabling the detection of single particles and improving sensitivity by several orders of magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high numerical apertures are used for single bead identification, then optical resolution is improved, but optical aberrations increase significantly
Solution Approach 1:
The patent introduces a magnetic field as an intermediary mechanism to manipulate and concentrate magnetic beads at the sensor surface. By using magnetic actuation instead of relying solely on optical methods, the system can achieve single bead detection without requiring high numerical aperture optics that would introduce severe aberrations. The magnetic field serves as a mediator that enables precise bead positioning and concentration enhancement while avoiding the optical trade-off.
2Measurement precision
If optical detection sensitivity is increased to detect single particles, then detection limit is improved, but optical baseline drift and non-specific binding increase
Solution Approach 1:
The patent employs a magnetic field as an intermediary to enhance the concentration of magnetic beads at the sensor surface through magnetic actuation. This magnetic concentration effect allows for single particle detection with improved sensitivity while maintaining signal stability, as the magnetic field provides a controlled and reversible mechanism for bead accumulation without the drawbacks of optical baseline drift or non-specific binding associated with purely optical detection methods.
Solution Approach 2:
The system dynamically adjusts the magnetic field strength and configuration to optimize bead concentration at the sensor surface. By changing magnetic field parameters (strength, gradient, duration), the system can achieve the necessary bead concentration for single particle detection while maintaining control over the detection process and minimizing false signals from non-specific binding.
3Force
If magnetic field strength is increased for better particle actuation, then particle manipulation is improved, but interference with optical detection may occur
Solution Approach 1:
The patent employs a segmented magnet assembly with multiple magnetic elements arranged in a specific configuration. This segmentation allows the magnetic field to be distributed and focused in a controlled manner, providing sufficient actuation force for particle manipulation while minimizing localized field gradients that could cause optical interference. The segmented structure enables independent optimization of different magnetic field zones.
Solution Approach 2:
The magnetic field is designed with spatially varying strength and direction, creating localized high-field regions for effective particle actuation while maintaining lower field strengths in regions where optical detection occurs. This local quality optimization ensures that magnetic actuation is effective where needed while minimizing interference with the optical detection pathway.
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 system achieves a minimum detectable target concentration of 1 fM, enhancing sensitivity by 2-3 orders of magnitude and allowing for precise detection of single particles, reducing the impact of non-specific binding and optical aberrations, and enabling accurate analysis of binding states and concentrations.
Implementation Method 1
a biosensor magnet assembly on one side of the cartridge for generating a magnetic field effective at the cartridge and the sensor surface
Implementation Method 2
a first optical detection system for detecting the particles arranged at the same side of the cartridge as the magnet assembly, whereas the magnet assembly is designed in a way that the optical detection is accomplished through the gap of the magnet assembly
Implementation Method 3
a second optical detection system for detecting the particles, providing the light for the first optical detection system by scattering of light at the particles
Implementation Method 4
A recently known magnetic biosensor system makes use of Frustrated Total Internal Reflection (FTIR) to detect the presence of magnetic beads near a surface of an assay
Data Source
AI summary
A biosensor system for the detection of particles includes a biosensor cartridge having a sensor surface. A biosensor magnet assembly is disposed on one side of the cartridge for generating a magnetic field effective at the cartridge and the sensor surface. The biosensor magnet assembly includes at least two magnetic sub-units separated by a gap. A first optical detection system detects the particles arranged at the same side of the cartridge as the magnet assembly. The magnet assembly and the first optical sensor are disposed such that the optical detection is accomplished through the gap of the magnet assembly.