Zona Pellucida Thinning via Reducing Agents for In Vitro Fertilization

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Solution Overview

Problem

In vitro fertilization faces challenges with sperms showing low fertilizing capacity, such as dysplastic or cryopreserved sperms, which struggle to pass through the ovum's zona pellucida, and frozen ova with hardened zona pellucida, leading to low fertilization and implantation rates, requiring specialized technologies and methods that are not highly versatile.

Innovation Solution

Treatment of mammalian ova or embryos with a culture medium containing reducing agents like reduced glutathione or DTT to thin or eliminate the zona pellucida, allowing for improved fertilization and development rates without the need for specialized technologies or apparatuses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If zona pellucida partial dissection or laser drilling methods are used to enhance fertilization rate, then fertilization rate is improved, but device complexity and operation difficulty increase due to requirement of specialized technologies and apparatuses

Engineering Contradiction:

Improvefertilization rateVSAvoidspecialized technologies and apparatuses

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical methods (needle dissection, laser drilling) with a chemical method using reducing agents to thin and eliminate zona pellucida. This substitution eliminates the need for complex mechanical apparatuses while achieving the same fertilization enhancement effect through biochemical action on the zona pellucida's disulfide bonds

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the chemical parameters of the zona pellucida by introducing reducing agents that alter the disulfide bond structure. This chemical parameter change makes the zona pellucida more permeable to sperm, achieving fertilization enhancement without mechanical intervention

Inventive Principle:

Principle #35Parameter changes

2Reliability

If mechanical injection methods like ICSI are used for sperms with no motility, then fertilization is achieved, but device complexity and operation difficulty increase

Engineering Contradiction:

Improvefertilization capabilityVSAvoidoperation difficulty

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies preliminary chemical treatment to the zona pellucida before fertilization occurs. By pre-thinning or eliminating the zona pellucida with reducing agents, the path of least resistance is created for sperm penetration, eliminating the need for complex mechanical injection procedures

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If zona pellucida is thickened or hardened by freezing, then ovum preservation is achieved, but fertilization rate decreases due to reduced sperm penetration capability

Engineering Contradiction:

Improveovum preservationVSAvoidfertilization rate

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent converts the harmful effect of zona pellucida hardening (caused by freezing) into a beneficial situation by applying reducing agents that specifically target and break down the hardened structure. The freezing-induced hardening, which normally prevents sperm penetration, is transformed into an opportunity to chemically modify and thin the zona pellucida, restoring fertilization capability

Inventive Principle:

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

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 method significantly enhances fertilization and implantation rates, simplifies the in vitro fertilization process, and is applicable for producing genetically modified animals by facilitating the production of embryos with thinned or eliminated zona pellucida, using organism-derived glutathione with low toxicity.

Implementation Method 1

treating a mammalian ovum or embryo with a reducing agent having SH groups (for example, reduced glutathione or DTT), and that fertilization rate and development rate can be improved

Methodology Applied

Scientific EffectReduction: Reduction

Data Source

PatentUS9994868B2Method and culture medium for preparing mammalian ovum or embryo in which zona pellucida has been thinned or eliminated, and method for fertilization using mammalian ovum prepared by same method

Publication Date: 2018.06.12 NAT UNIV CORP KUMAMOTO UNIV

AI summary

Provided are a method for preparing a mammalian ovum or embryo in which zona pellucida has been thinned or eliminated, and a method for fertilization using the mammalian ovum prepared by the aforementioned method. The resulting mammalian ovum or embryo is capable of realizing an improved fertilization rate and development rate when used for in vitro fertilization, transplantation of a fertilized ovum, or for preparation of an embryo in the early stages of development used in the production of a genetically modified animal.