Discrete Contact MR Bio-Sensor with Magnetic Label Alignment
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Solution Overview
Problem
Existing micro-particle assays face challenges with random label binding sites, signal fluctuations due to label location variations, and large sensor size limitations, which hinder accurate single label and single molecule detection.
Innovation Solution
A method using a well-shaped structure with a continuous MR sensor and controlled field gradient to align magnetic labels uniformly, minimizing label-to-sensor distance variations and eliminating noise by edge pinning, enabling precise localization and simultaneous detection of multiple biological entities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If magnetic labels are bound randomly on the sensor surface, then the binding assay can be performed, but signal fluctuations occur due to label location variations
Solution Approach 1:
The patent applies a controlled magnetic field gradient before the detection process to pre-align magnetic labels along the sensor edge. This preliminary alignment action ensures that labels are positioned in a controlled manner rather than randomly, thereby reducing signal fluctuations while maintaining the binding assay capability
Solution Approach 2:
The patent creates a non-uniform magnetic field distribution with a gradient that concentrates labels at specific locations (along the sensor edge). This local concentration of labels in a controlled region improves measurement precision by eliminating the randomness of label positions across the entire sensor surface
2Device complexity
If the MR sensor size is reduced for miniaturization, then device complexity and form factor improve, but detection precision and signal strength deteriorate
Solution Approach 1:
The patent transitions from a two-dimensional sensor surface to a three-dimensional configuration by positioning the sensor beneath a well structure and utilizing vertical magnetic field gradients. This dimensional change allows the sensor to detect labels at multiple positions (along the well edge) rather than requiring a large planar sensor area
Solution Approach 2:
The patent segments the detection function by using multiple discrete contact pads arranged in an array. Each contact pad can independently detect signals from labels at different positions along the well edge, allowing a compact sensor structure to achieve high spatial resolution through functional segmentation
3Manufacturing precision
If discrete contact pads are used instead of continuous sensor, then label alignment precision improves, but sensor variations and noise increase
Solution Approach 1:
The patent merges multiple discrete contact pad signals into a unified detection system. By processing signals from multiple contact pads in an array and identifying peak patterns across the array, the system achieves high alignment precision while compensating for individual sensor variations through ensemble measurement
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 achieves high spatial resolution and accurate detection of single biological entities by minimizing signal fluctuations and sensor variations, allowing for precise counting and identification of magnetic entities with peak pattern recognition.
Implementation Method 1
there is a gradient over the region where the walls and floor of the well meet. This has the effect of drawing the target molecules or cells under detection up against the wall and floor
Implementation Method 2
detect the magnetic field emanating from the bound magnetic labels with magneto-resistive (MR) sensors. This magnetic field from the magnetic labels can then change the MR sensor's resistance state
Data Source
AI summary
The invention describes a family of sensors for assaying macro-molecules and/or biological cells in solution. The invention also describes methods of making and using the sensors. Each sensor has the form of a well (a hollow cylinder having a floor but no lid) or a trench whose walls comprise a plurality of GMR or TMR devices. Suitably shaped magnets located below each well's floor pull labeled particles into the well/trench and up against the inner wall where a field gradient orients them for optimum detection. Any unattached labels that happen to also be in the well/trench are removed through suitably sized holes in the floor.