What Medical Device Teams Should Validate Before Switching to PFAS Free Self Lubricating LSR
A new silicone grade can solve a real engineering problem and still create a risky material change if the team treats the supplier data sheet as the finished-device approval. That distinction matters now because PFAS-free materials are moving into applications where low friction, reliable valve movement and efficient molding all need to work together.
On October 15, 2026, Bluestar Silicones announced SILBIONE LSR 4755 PF, a PFAS-free, self-lubricating liquid silicone rubber intended for selected healthcare applications with patient contact up to 30 days. The supplier highlights delayed oil bleed, mold release, tear strength and uses such as needle valves, check valves, duckbill valves and other one-way valves. It also states that the material has been evaluated according to ISO 10993 requirements for applications involving less than 30 days of body contact. [1]
This is a useful industry development, but it does not mean every existing medical silicone component should be changed immediately. At DX, we would treat a PFAS-free self-lubricating LSR as a candidate material that must be matched to the device, the contact profile, the molding process and the finished-part validation plan. We are not claiming that DX has qualified or used this specific Bluestar grade; it is discussed here as a recent supplier example.
PFAS free is a material attribute not a finished device approval
The phrase PFAS-free can be important to a purchasing policy or sustainability objective, but it does not answer every safety or performance question. PFAS is a broad class of substances. In its September 1, 2026 update, the U.S. FDA emphasized that fluoropolymers used in medical devices differ from the smaller PFAS commonly associated with environmental contamination and that the agency sees no reason to restrict the continued use of fluoropolymers in medical devices based on current evidence. The FDA also explains that it regulates finished devices, not individual materials in isolation. [2]
That creates a more useful decision framework. A brand should not switch simply because PFAS-free sounds newer, and it should not reject every fluoropolymer without examining its function. The team should compare the old and proposed material against the actual device requirements, then document why the change improves the product or supply strategy without introducing unacceptable risk.
Start with the exact device contact profile
Before reviewing a supplier certificate, define how the silicone component is used. ISO 10993-1:2025 places biological safety within a risk-management process and considers material composition, tissue contact and exposure duration. FDA guidance follows the same risk-based principle and asks about the nature, type, frequency and duration of contact. [3, 4]
For a proposed medical silicone material, we would ask:
The supplier announcement for SILBIONE LSR 4755 PF refers to applications involving contact of less than 30 days. That statement should not be stretched to permanent implantation, a different tissue-contact category or a different finished-device process without a separate assessment.
Define what the PFAS free claim covers
Procurement teams need a claim that can be placed into a controlled specification. Ask the material supplier to define the scope of PFAS-free, the substance list or definition used, any reporting threshold, the test or declaration method and the status of pigments, additives and processing aids. If the finished part uses color masterbatch, ink, primer, release agent or another secondary material, those inputs also need review.
The objective is not to demand one universal test from every supplier. It is to prevent a broad marketing phrase from entering the approved drawing or purchase specification without a shared technical meaning. A supplier declaration, analytical report and contractual restricted-substance requirement serve different purposes; the project may need one or more of them depending on risk and customer requirements.
Validate the low friction function on the actual part
Self-lubricating silicone can be attractive when a valve, seal or moving interface needs lower friction without an applied lubricant. The important output, however, is not the material description. It is the part behavior after molding, aging and assembly.
For valves and slit components
A duckbill valve or one-way valve may need an agreed opening pressure, flow range, closing behavior, leakage limit and resistance to slit healing. Material hardness and lubricity influence those results, but so do slit geometry, wall thickness, cure, mold surface and cutting or secondary operations. A successful material trial should therefore use production-representative geometry and the intended fluid or test medium.
For assembly and moving interfaces
If lubricity is intended to reduce insertion force, sticking or actuation force, measure that function across a useful sample size and after relevant aging or sterilization. Check both initial performance and stability. An oil-bleed mechanism may be beneficial, but the team should confirm whether the surface changes over time, whether nearby components are affected and whether packaging or visual acceptance needs to be adjusted.
Run a molding study before committing the production tool
A material change can affect flow, cure, demolding, tear behavior, flash, venting and mold maintenance. The Bluestar announcement specifically positions delayed oil bleed as a way to reduce mold contamination compared with traditional self-lubricating materials. That is a supplier claim worth testing under the intended mold temperature, cavity layout and production interval. [1]
For a new custom LSR part, our practical sequence would be to review the geometry, establish a trial plan, mold samples with controlled parameters, inspect dimensions and appearance, run the functional test and record any mold deposits or release behavior over an agreed number of cycles. A short successful shot does not establish long-run process stability.
Where the material is replacing an existing grade, compare it against the current approved part. Keep the same test method, mating components and conditioning where possible. If the proposed grade changes hardness, oil migration, shrinkage or tear behavior, the tool and process window may also need adjustment.
Biocompatibility belongs to the finished device risk assessment
A material evaluation according to ISO 10993 is useful evidence, but it is not automatically the complete biological evaluation for a finished device. FDA states that biocompatibility is assessed on the final finished form, including sterilization where applicable, and that manufacturing methods and residuals from processing aids should be considered. [4]
For a material change, the device manufacturer should compare composition, processing, patient-contact conditions, sterilization and available historical evidence. The result may be a documented rationale, additional chemical characterization, selected biological testing or a broader validation program. The correct scope depends on the device and regulatory pathway; it should be set by the device manufacturer and its qualified regulatory or biological-safety team.
Use a controlled material change checklist
| Review area | Evidence to request or generate | Decision it should support |
| PFAS free scope | Supplier definition, declaration, substance list, threshold and test basis | Whether the claim matches the brand or market requirement |
| Contact profile | Tissue type, direct or indirect contact, cumulative duration and patient population | Whether the supplier evidence is relevant to the intended use |
| Functional performance | Opening pressure, leakage, insertion or actuation force, aging and recovery | Whether lubricity improves the real component function |
| Molding process | Fill, cure, demolding, flash, tear, shrinkage, mold deposits and cycle observations | Whether the process is stable and the tooling strategy remains suitable |
| Finished device safety | Composition review, processing aids, sterilization, residuals and biological risk assessment | Whether additional evaluation or testing is required |
| Change control | Approved specification, traceability, supplier change notification and regulatory assessment | Whether the material can enter controlled production |
How DX can support a medical silicone development project
DX provides liquid silicone injection molding, in-house tooling support and technical review for custom silicone parts. Our website lists medical products among the recommended LIM applications, and our quality-control capabilities include raw-material control, dimensional checks and mechanical-property testing. DX also lists ISO 13485 among its certifications. [7, 8]
For a PFAS-free or self-lubricating LSR project, we can review the drawing, part geometry, molding route, tooling requirements, dimensional plan and production testing needs. Material availability, supplier documentation, regulatory suitability and any project-specific validation must be confirmed before approval; we would not treat a new supplier announcement as a prequalified DX production material.
A useful enquiry package should include:
Discuss your custom medical silicone component with DX
Developing a custom silicone valve, seal, diaphragm or other precision LSR component? Send DX your drawing, dimensions, application and contact conditions, material requirements, functional test targets and expected quantity. We can review the tooling and manufacturing approach and identify the evidence that should be confirmed before production. Contact DX to discuss your custom silicone product.
References
1. Bluestar Silicones announcement dated October 15 2026 for SILBIONE LSR 4755 PF
2. U.S. FDA PFAS in Medical Devices updated September 1 2026
3. ISO 10993-1 2025 biological evaluation of medical devices
4. U.S. FDA basics of biocompatibility and final finished device assessment
5. U.S. FDA guidance on use of ISO 10993-1
6. European Chemicals Agency PFAS topic and restriction updates
7. DX Silicone liquid injection molding
8. DX Silicone quality control
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