Microfluidic Sperm Separation via Rheotaxis
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Solution Overview
Problem
Current microfluidic sperm preparation devices are limited in processing physiologically relevant volumes for clinical use in IUI and fail to isolate sufficient motile sperm, especially for patients with low sperm counts, due to their inability to handle sperm with varying motilities and generate low sample quality during centrifugation.
Innovation Solution
A point-of-care microfluidic device that utilizes sperm rheotaxis to concentrate motile sperm by creating a flow velocity range of 17 to 100 μm/s, allowing motile sperm to remain in the separation zone while non-motile sperm and other cells are flushed out, without the need for mechanical centrifugation, thereby improving sperm quality and concentration to meet IUI guidelines (>10 million sperm).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If mechanical centrifugation is used for sperm separation, then sperm concentration is improved, but reactive ion species are generated reducing sample quality
Solution Approach 1:
The patent replaces the mechanical centrifugation system with a microfluidic device that utilizes rheotaxis (fluid flow-induced directional movement) to separate motile sperm from non-motile sperm. The microfluidic device creates specific flow velocity ranges (17 to 100 μm/s) that cause motile sperm to swim against the flow and accumulate in the separation zone, while non-motile sperm are carried away by the flow, eliminating the need for mechanical centrifugation and the generation of reactive ion species.
2Object-generated harmful factors
If existing microfluidic devices separate only progressively motile sperm, then sample quality is improved, but sample retrieval volume is limited
Solution Approach 1:
The patent changes the flow velocity parameter within a specific range (17 to 100 μm/s) to capture sperm with varying motilities, not just progressively motile sperm. By optimizing the flow velocity, the device can retain sperm with minimal motility in the separation zone, thereby increasing the total number of recoverable sperm while maintaining sample quality.
3Ease of operation
If conventional IUI procedures are used, then treatment is simple, but success rate is low requiring multiple cycles
Solution Approach 1:
The microfluidic device performs self-service separation by utilizing the inherent rheotaxis behavior of motile sperm. The device automatically concentrates motile sperm through controlled fluid flow without requiring external mechanical intervention or complex operational steps, maintaining procedural simplicity while achieving reliable sperm concentration (>10 million sperm) that improves IUI success rate.
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 device effectively increases the concentration of motile sperm to meet clinical guidelines, reducing the number of IUI cycles and improving treatment success rates by passively enhancing sperm quality, making it suitable for IUI procedures.
Implementation Method 1
causing the fluid sample to flow through a separation portion of the microfluidic device at a flow velocity within a rheotaxis range such that motile sperm in the sample undergo rheotaxis and remain in the separation
Data Source
AI summary
The present disclosure provides methods and devices for separation of motile sperm. A method of separating motile sperm comprises: introducing a fluid sample comprising motile sperm to an inlet portion of a microfluidic device; and causing the fluid sample to flow through a separation portion of the microfluidic device at a flow velocity within a rheotaxis range such that motile sperm in the sample undergo rheotaxis and remain in the separation whereas a part of the fluid sample flows out of the separation zone through an outlet portion of the microfluidic device.