Microfluidic Sense Region for Single-File Particle Counting
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Solution Overview
Problem
Current microfluidic devices face challenges in achieving high throughput and accuracy for cytology applications, particularly in counting biologic particles, due to limitations in signal-to-noise ratios and fluid dilution factors, which hinder efficient point-of-care diagnostic testing.
Innovation Solution
The implementation of a microfluidic device with a sense region of the same order of magnitude as the biologic particle volume, utilizing a non-uniform flow field created by an exclusion structure and low fluid dilution, enables single file sensing and counting of biologic particles, facilitated by on-board pumps, heaters, and sensors, achieving up to 1 million particles per second throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional microfluidic devices are used for particle counting, then device complexity is reduced, but measurement precision and productivity deteriorate due to low signal-to-noise ratios and inability to achieve single-file particle flow
Solution Approach 1:
The microfluidic channel incorporates a constriction region with specific dimensional characteristics (width and height) that are locally optimized to match the size of target particles. This local structural modification creates a sensing volume where particles pass through in single-file fashion, enabling precise detection while maintaining overall device simplicity. The constriction region dimensions are specifically designed to be comparable to particle dimensions, ensuring one-at-a-time particle passage.
Solution Approach 2:
The microfluidic channel is segmented into distinct functional regions: an inlet region, a constriction region with sensing volume, and an outlet region. This segmentation allows the constriction region to specifically address the measurement precision requirement while other regions handle fluid transport, thereby resolving the contradiction between accuracy and device complexity.
2Productivity
If high throughput particle sensing is achieved through conventional methods, then productivity increases, but measurement precision deteriorates due to poor signal-to-noise ratios and fluid dilution
Solution Approach 1:
The channel dimensions in the constriction region are specifically parameterized to create a sensing volume where the probability of multiple particles being present simultaneously is minimized. By adjusting the width and height parameters of the constriction to match particle size parameters, the system achieves single-file flow conditions that improve signal-to-noise ratio while maintaining high throughput capability.
Solution Approach 2:
The inlet region is designed to preliminarily condition the particle stream before it enters the constriction region, ensuring particles are properly positioned and spaced. This preliminary action prepares the particle flow for optimal single-file passage through the sensing volume, enabling both high throughput and high precision measurement.
3Measurement precision
If single-file particle sensing is implemented, then measurement precision improves, but device complexity increases due to requirements for specific channel constrictions and flow control mechanisms
Solution Approach 1:
The inlet region and constriction region are merged into a continuous microfluidic channel structure without requiring separate components or complex assembly. The gradual transition from inlet to constriction region is integrated into a single fabricated structure, reducing device complexity while maintaining the single-file sensing capability.
Data Source
AI summary
A device including a microfluidic channel structure formed on a substrate and including a first channel and a fluid actuator within the microfluidic channel structure. A sense region within the first channel is to receive a fluid flow of target biologic particles for counting in a single file pattern, with the sense region having a volume on a same order of magnitude as a volume of a single one of the target biologic particles.