Gas Permeable Membrane for Pulsatile Perfusion Preservation

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Solution Overview

Problem

Current methods for preserving living tissues, such as nonperfused cold storage, have limitations due to oxygen decline and pressure gradients that can damage tissues during pulsatile perfusion, leading to reduced storage time and viability, especially under hypothermic conditions.

Innovation Solution

A preservation apparatus with a storage compartment and a gas permeable membrane that allows for oxygenated perfusion, using a non-planar support element and unidirectional valves to manage fluid flow and pressure, ensuring continuous oxygen supply and minimizing capillary damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If pulsatile perfusion is used to extend tissue viability, then storage time is extended, but capillary damage occurs due to pressure gradients

Engineering Contradiction:

Improvestorage timeVSAvoidcapillary damage

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

A compliant membrane is introduced as an intermediary between the perfusion pump and the tissue capillaries. This membrane acts as a pressure buffer that absorbs pressure spikes and gradients, allowing pulsatile flow to be delivered without transmitting damaging pressure forces to the capillary walls, thus extending storage time safely

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the physical parameters of pressure transmission by using a compliant membrane with specific elasticity properties. This transforms the pressure profile from high-gradient pulsatile flow into a moderated flow pattern that maintains perfusion benefits while eliminating capillary damage risks

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If nonperfused cold storage is used to preserve tissue, then device complexity is reduced, but oxygen supply is insufficient leading to reduced viability

Engineering Contradiction:

Improvedevice complexityVSAvoidtissue viability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The invention uses pneumatic actuation through a compliant membrane to create hydraulic flow of perfusate through the tissue. Gas pressure applied to the membrane translates into controlled fluid flow, providing oxygenated perfusion without requiring complex mechanical pumps or electrical systems, thus maintaining simplicity while improving viability

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system utilizes the phase transition capability of gas to liquid through the compliant membrane, where gas pressure applied to the membrane interface converts into controlled liquid perfusate flow, enabling perfusion function through a simple pressure-driven mechanism

Inventive Principle:

Principle #36Phase transitions

3Duration of action of stationary object

If hypothermic pulsatile perfusion is used to extend storage time, then metabolic rate is reduced, but device portability is compromised

Engineering Contradiction:

Improvestorage timeVSAvoiddevice portability

Core Design Contradiction:

Duration of action of stationary objectVSWeight of moving object

Solution Approach 1:

The invention extracts and eliminates the heavy components (electrical pumps, power supplies, complex control systems) from the perfusion device, retaining only the essential pneumatic-membrane-hydraulic mechanism. This extracted simplified system provides the same physiological benefits with dramatically reduced weight and portability requirements

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex mechanical/electrical pump systems with a pneumatic-membrane system. Gas pressure application to the compliant membrane substitutes for motor-driven pumps, eliminating the need for electrical power and heavy mechanical components while maintaining perfusion functionality

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 apparatus extends tissue viability by maintaining a continuous oxygen supply, reducing metabolic stress, and preventing capillary damage, thereby increasing storage time to 12-24 hours without loss of viability, even under hypothermic conditions.

Implementation Method 1

a gas permeable membrane that allows for oxygenated perfusion

Methodology Applied

Scientific EffectGas permeation: Permeation

Data Source

PatentUS8685709B2Fluidics based pulsatile perfusion preservation device and method

Publication Date: 2014.04.01 BOARD OF RGT THE UNIV OF TEXAS SYST

AI summary

In one embodiment, a preservation apparatus is described that includes a storage compartment. The storage compartment is configured to hold an organ or tissue and a preservation fluid. A cover assembly is configured to engage the storage compartment. The cover assembly includes a support element, wherein the support element together with the storage compartment define a storage chamber. The cover assembly also includes a lid and a gas permeable membrane disposed between the lid and the support element. The gas permeable membrane and the support element together define a perfusion chamber configured to hold preservation fluid and an organ or tissue during use.