Microfluidic Sperm Sorting Using Rheotaxis Instead of Centrifugation

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Solution Overview

Problem

Current sperm sorting and processing methods, such as centrifugation, cause damage to sperm cells and introduce biases, failing to mimic natural sperm selection processes, leading to suboptimal outcomes in assisted reproductive technologies.

Innovation Solution

A microfluidic system utilizing rheotaxis principles to sort healthy motile sperm by allowing them to swim against fluid flow, eliminating centrifugation and harmful substances, and incorporating a flexible housing with inlets, outlets, and a flow channel to facilitate sperm collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If centrifugation is used for sperm sorting, then sperm concentration can be increased, but sperm cell damage and DNA fragmentation occur

Engineering Contradiction:

Improvesperm concentrationVSAvoidsperm cell damage

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the centrifugation step from the sperm processing workflow. Instead of using centrifugal force to separate sperm, the system employs microfluidic channels with controlled fluid flow to achieve sperm concentration and selection without mechanical stress that causes cell damage

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical centrifugation system with a microfluidic system that uses controlled fluid flow and rheotaxis (sperm's natural ability to swim against flow) to achieve sperm separation and concentration without the harmful mechanical forces of centrifugation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If centrifugation is used for sperm processing, then sperm can be concentrated, but inflammatory cells and immature sperm are included in the pellet

Engineering Contradiction:

Improvesperm concentrationVSAvoidsperm quality

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent creates different flow conditions in different regions of the microfluidic device. The main channel has flow conditions that allow healthy motile sperm to swim against the flow and be concentrated, while other regions handle waste and non-motile sperm differently, achieving selective concentration based on local flow characteristics

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes the sperm's own motility and rheotactic behavior as the separation mechanism. Healthy sperm naturally swim against the fluid flow in the microchannel, automatically separating themselves from non-motile sperm and cellular debris without requiring external intervention or additional sorting steps

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If current sperm sorting methods are used, then sperm can be processed, but natural sperm selection mechanisms are not mimicked

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidbiological fidelity

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent converts the fluid flow, which could be seen as a阻碍 to sperm movement, into a beneficial separation mechanism. By introducing controlled flow in the microchannel, the system exploits rheotaxis to enhance the selection of healthy sperm while removing harmful substances and non-motile cells, thus turning potential harm into benefit

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the physical parameters of the fluid environment (flow rate, channel dimensions, viscosity) to create conditions that mimic the female reproductive tract while enabling efficient sperm selection. The microchannel geometry and flow conditions are optimized to reproduce natural selection pressures without requiring complex biological systems

Inventive Principle:

Principle #35Parameter changes

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 system efficiently selects motile, healthy sperm while reducing damage, improving sperm quality for assisted reproductive technologies by mimicking natural selection mechanisms, enhancing pregnancy outcomes.

Implementation Method 1

A microfluidic system utilizing rheotaxis principles to sort healthy motile sperm by allowing them to swim against fluid flow

Methodology Applied

Scientific EffectRheotaxis:

Data Source

PatentUS12491515B2Systems and methods for sperm selection

Publication Date: 2025.12.09 FLORIDA ATLANTIC UNIVERSITY RESEARCH CORP

AI summary

Systems for sorting sperm include a housing and a microfluidic system supported by the housing. The systems also include two or more inlets providing access to the microfluidic system to deliver sperm or semen and fluid to the microfluidic system, as well as an outlet for harvesting sorted sperm. The systems include a flow channel that provides a flow path for sperm from an inlet to an outlet while sperm travels against a fluid flow towards an outlet for harvesting. In the systems, fluid delivered to the microfluidic system via an inlet flows from the inlet towards one or more outlets, and the flow channel extending along the length of the microfluidic system provides a flow path for motile sperm to travel against the fluid flow towards a collection outlet for harvesting. In some embodiments of a system, the microfluidic system also includes a microporous filter arranged in the flow path between the inlet and the collection outlet to cause motile sperm traveling against the fluid flow to pass through the filter to reach the collection outlet for harvesting.