PFAS-Free Infusion Cannulas for Prolonged Insulin Delivery

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Solution Overview

Problem

Cannulas made from polytetrafluoroethylene (PTFE) and fluoroethylenepropylene (FEP) contain per- and polyfluoroalkyl substances (PFAS) that are harmful to human health and the environment, and there is a need for biocompatible, PFAS-free materials that can deliver insulin subcutaneously for extended periods without adverse effects.

Innovation Solution

The use of a polycarbonate polyurethane polysiloxane (PC-PU-PS) copolymer as a PFAS-free material for cannulas, which is configured for subcutaneous insertion and designed to minimize foreign body response, mechanical trauma, and infusion site-loss, with a manufacturing process that maintains stiffness and flexibility suitable for prolonged insulin delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If PTFE and FEP polymers are used for cannulas, then ease of manufacturing and biocompatibility are improved, but harmful PFAS substances accumulate in the body and environment

Engineering Contradiction:
Improveease of manufacturingVSAvoidadverse effects to human health
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material composition parameter by replacing PTFE/FEP polymers with a copolymer consisting of polyether block copolyester and polysiloxane. This substitution maintains the desired mechanical properties and biocompatibility while eliminating harmful PFAS substances, thus resolving the contradiction between ease of manufacture and harmful effects to human health.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite material approach by creating a copolymer that combines polyether block copolyester and polysiloxane in specific ratios (50-90% polyether block copolyester and 10-50% polysiloxane). This composite structure achieves both manufacturability and safety by leveraging the complementary properties of the two polymers while avoiding PFAS accumulation.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If PTFE and FEP polymers are used for cannulas, then lubricious properties and ease of insertion are improved, but PFAS chemicals build up over time in the body

Engineering Contradiction:
Improveease of insertionVSAvoidaccumulation over time
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the material composition by using a copolymer of polyether block copolyester and polysiloxane, which provides adequate lubricious properties for ease of insertion while being biodegradable and non-accumulative. This resolves the contradiction by changing the chemical composition parameter to eliminate long-term accumulation issues.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent promotes the use of disposable cannulas made from the new copolymer material, which are designed for single-use or limited-duration application. This approach prevents long-term accumulation in the body by ensuring the cannula is removed and replaced before any potential buildup occurs, while the material's biodegradability ensures no harmful residue remains.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If PTFE and FEP polymers are used for cannulas, then reliable insulin delivery is achieved, but immune system response and inflammation occur

Engineering Contradiction:
Improvereliable insulin deliveryVSAvoidimmune system response
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the material composition from PTFE/FEP to a copolymer of polyether block copolyester and polysiloxane, which maintains the reliability of insulin delivery through consistent flow properties while reducing immunogenicity. The new material's chemical structure is less likely to trigger immune responses, thus resolving the contradiction between reliability and harmful immune system effects.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a homogeneous copolymer structure where polyether block copolyester and polysiloxane are integrated at the molecular level. This homogeneity ensures consistent material properties for reliable insulin delivery while the uniform composition reduces the likelihood of triggering localized immune responses compared to heterogeneous or impure materials.

Inventive Principle:
Principle #33Homogeneity

Data Source

PatentEP4643911A1PFAS-free infusion cannulas
Publication Date: 2025.11.05 MEDTRONIC MINIMED INC
  • EP4643911A1 patent drawingFigure 1
  • EP4643911A1 patent drawingFigure 2
  • EP4643911A1 patent drawingFigure 3

AI summary

The present disclosure relates to the use of a PFAS-free cannula in delivering a fluid medication, such as insulin, to a subcutaneous site. The cannula comprises polycarbonate polyurethane polysiloxane (PC-PU-PS), wherein the cannula is configured for subcutaneous insertion into the tissue of the individual in need thereof. The disclosure includes methods for administering insulin using the cannula and infusion devices comprising the cannula.