Microfluidic Assay Channel Monitoring via Detectable Tracer

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Solution Overview

Problem

Microfluidic assay systems face challenges in accurately monitoring and detecting fluid flow within tiny channels due to the difficulty in visualizing flows and potential for human errors, leading to inconsistent results and contamination issues, especially in portable cartridges where precise control of reagents and sample flow is crucial for accurate quantification.

Innovation Solution

Incorporating a method that uses a detectable tracer in the assay fluid to monitor the condition and location of microfluidic channels, employing epi-fluorescence detection with a laser beam to excite fluorescence and determine the precise location of channel elements, and using active capture agents configured to define codes on the interior surfaces of micro-length tubes for precise analyte capture and quantification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If microfluidic channels are made tiny to enable portable cartridge assays, then portability and integration are improved, but flow visualization and monitoring become difficult leading to inconsistent results

Engineering Contradiction:

Improvechannel sizeVSAvoidflow monitoring accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

A detectable tracer is introduced as an intermediary substance that flows with the assay fluid through the microfluidic channel. The tracer provides a measurable signal (fluorescence, absorbance, or other detectable property) that enables indirect monitoring of fluid flow, channel location, and channel condition without requiring direct visualization of the tiny channel structures themselves.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The detectable tracer exhibits optical property changes (such as fluorescence emission, absorbance, or color change) that allow visual or instrumental detection of fluid presence and flow characteristics in the microfluidic channel. This transforms the invisible flow into a detectable signal, resolving the contradiction between small channel size and monitoring capability.

Inventive Principle:

Principle #32Color changes

2Device complexity

If manual monitoring methods are used in microfluidic systems, then device complexity is reduced, but human errors increase leading to contamination and inconsistent results

Engineering Contradiction:

Improvemonitoring system complexityVSAvoidassay consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

A detection system continuously monitors the detectable tracer signal and provides feedback information about fluid flow status, channel location, and channel condition. This automated feedback mechanism replaces manual monitoring, reducing human error while maintaining or reducing system complexity through intelligent sensing and computational analysis.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

Manual visual inspection and physical monitoring methods are replaced with optical, electromagnetic, or other non-contact detection systems that automatically track the tracer signal. This substitution eliminates human involvement in the monitoring process, improving reliability without significantly increasing mechanical complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If capture agent surface area is increased to improve analyte capture, then capture efficiency is improved, but analyte depletion increases reducing assay sensitivity

Engineering Contradiction:

Improvecapture agent amountVSAvoidanalyte depletion

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The capture agent distribution is optimized by creating local variations in surface properties or capture agent density within the microfluidic channel. This allows concentrated capture zones where analyte binding is needed while maintaining lower overall surface area exposure, preventing excessive analyte depletion while preserving capture efficiency in critical regions.

Inventive Principle:

Principle #3Local quality

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 enables precise monitoring and detection of assay results with improved accuracy and consistency, reducing the coefficient of variation to less than 10% and minimizing surface area exposure to prevent analyte depletion, thus enhancing the sensitivity and reliability of microfluidic assays.

Implementation Method 1

employing epi-fluorescence detection with a laser beam to excite fluorescence and determine the precise location of channel elements

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

a method uses a detectable tracer in the assay fluid to monitor the condition and location of microfluidic channels

Methodology Applied

Scientific EffectRadioactive tracing: Radioactive Tracing

Data Source

PatentUS10076752B2Methods and systems for manufacture of microarray assay systems, conducting microfluidic assays, and monitoring and scanning to obtain microfluidic assay results

Publication Date: 2018.09.18 CYVEK INC

AI summary

A method of flowing a fluid with a tracer in a microfluidic channel of an assay device and detecting the tracer for determining the channel location or condition of the channel.