Multi-point Capacitive Motion Sensing for Microfluidic Particle Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical sensing methods for detecting particles in fluidic devices are limited by low detection resolution, especially for submicron particles and those without optical contrast, and are not portable or scalable for in-field use.
Innovation Solution
A capacitive probe structure with multiple microfluidic channels and probes extending through dielectric layers, allowing non-invasive measurement of particle concentrations and flow, using capacitive sensing to detect particles based on dielectric changes without direct contact, thus overcoming contamination and resolution limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensing methods are used to detect particles in fluidic devices, then detection capability is provided, but detection resolution is limited especially for submicron particles and particles without optical contrast
Solution Approach 1:
The patent replaces optical sensing mechanisms with electrical capacitive sensing mechanisms. Instead of using optical systems (microscopes, cameras, light sources) to detect particles, the invention uses capacitive probes that measure changes in electrical capacitance caused by particles passing through microfluidic channels. This substitution enables detection of submicron particles and particles without optical contrast by detecting their electrical properties rather than optical properties.
Solution Approach 2:
The invention changes the detection parameter from optical properties (reflectivity, absorption, fluorescence) to electrical properties (capacitance). By measuring capacitance changes as particles pass through the sensing zone, the system can detect particles based on their dielectric properties, which provides superior resolution for submicron particles and particles lacking optical contrast compared to traditional optical methods.
2Adaptability or versatility
If conventional optical sensing systems are used, then particle detection is achieved, but the systems are large and bulky and confined to laboratory environments
Solution Approach 1:
The invention segments the sensing system into integrated microfluidic channels with embedded capacitive probes, combining multiple functions (fluid transport, particle introduction, sensing) into a single compact unit. This integration eliminates the need for separate optical components (microscopes, cameras, light sources) and enables portable, field-deployable devices while maintaining detection capabilities.
Solution Approach 2:
The capacitive probe structure serves multiple functions: it acts as both the sensing element and part of the microfluidic channel structure. The dielectric layers and probes are integrated into the channel walls, eliminating the need for separate optical components and enabling the system to be miniaturized for portable applications while maintaining versatility in detecting various particle types.
3Measurement precision
If optical sensing is used, then detection is provided, but fluorescent tags are required to overcome low contrast in detecting bare analyte particles
Solution Approach 1:
The patent replaces optical detection that requires fluorescent tagging with electrical capacitive detection. By measuring capacitance changes directly, the system can detect bare analyte particles without requiring fluorescent tags or other contrast-enhancing modifications, simplifying sample preparation while maintaining or improving detection precision.
Solution Approach 2:
The invention changes the detection parameter from optical contrast (which requires fluorescent tags for bare particles) to electrical capacitance measurement. This parameter change enables direct detection of bare analyte particles based on their intrinsic dielectric properties, eliminating the need for fluorescent tagging and reducing sample preparation complexity.
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 capacitive probe structure provides scalable, low-power, cost-effective, and portable detection of particles and fluids, capable of sensing both conductive and non-conductive liquids and gases, with improved resolution for submicron particles and real-time monitoring, eliminating interference from the Helmholtz layer.
Implementation Method 1
capacitive sensing to detect particles based on dielectric changes without direct contact
Implementation Method 2
detect particles based on dielectric changes
Data Source
AI summary
A capacitive probe structure is presented including two or more microfluidic channels defined within a plurality of dielectric layers disposed over a substrate, and a plurality of probes extending through the plurality of dielectric layers such that several probes of the plurality of probes extend to the two or more microfluidic channels to measure at least particle concentrations and particle flow within the two or more microfluidic channels. The plurality of probes are physically and electrically isolated from each other by the plurality of dielectric layers. The plurality of probes further measure a dielectric constant change for conducting and non-conducting liquids and gasses within the two or more microfluidic channels.