Biocompatibility is a critical consideration when designing medical cable assemblies, particularly where cables, connectors or overmoulded components may come into direct or indirect contact with patients. The material selection process goes far beyond simply choosing a product marketed as “medical grade”.
A successful design must consider the intended application, patient-contact category, manufacturing processes, sterilisation methods, expected service life and relevant regulatory requirements. Decisions made early in development can have significant implications for performance, regulatory approval and long-term product reliability.
At Novara Technologies, we support medical device manufacturers in developing reliable cable assemblies and interconnect solutions for both reusable and single-use devices, helping to balance biocompatibility, manufacturability and performance throughout the product lifecycle.
What Does Biocompatibility Mean?
Biocompatibility refers to the ability of a medical device or material to perform its intended function without causing an unacceptable biological response.
For medical cable assemblies, this may apply to:
- Cable jackets
- Connector housings
- Overmoulded strain reliefs
- Adhesives and potting materials
- Coatings and surface finishes
- Manufacturing residues that may remain on the finished product
The requirements depend heavily on the nature and duration of patient contact. A cable that only contacts intact skin during a short procedure may have very different requirements from a component intended for repeated use in a patient-monitoring device or one that interfaces with damaged tissue.
This is why biocompatibility should always be assessed within the context of the complete device and its intended use rather than focusing solely on individual materials.
Selecting Medical-Grade Materials
Choosing suitable medical-grade materials at an early stage can help reduce the risk of expensive changes to the design later in the development process.
Choosing suitable materials early in development can help avoid costly redesigns, delays in verification testing and regulatory complications later in the project.
Common materials used within medical cable assemblies include:
Silicone
Silicone remains a popular choice for medical cables due to its:
- Excellent flexibility
- Wide operating temperature range
- Good resistance to repeated flexing
- Compatibility with many sterilisation processes
It is particularly suitable for applications requiring soft-touch handling or frequent movement.
Thermoplastic Polyurethane (TPU)
TPU is frequently selected where durability is a priority owing to its:
- Excellent abrasion resistance
- High tear strength
- Good cosmetic appearance
- Resistance to many cleaning agents
TPU is often preferred for reusable assemblies that will experience significant handling throughout their service life.
Thermoplastic Elastomers (TPE)
TPE materials can provide a balance between flexibility, durability and processability while allowing a broad range of formulation options to meet specific application requirements.
However, material selection must go beyond choosing a generic material family. Individual formulations may contain:
- Plasticisers
- Colourants
- Processing aids
- Stabilising additives
These can influence both long-term performance and biocompatibility. A material that performs well mechanically may not necessarily be appropriate for a particular patient-contact application.
Understanding ISO 10993 and Biological Evaluation
The term “ISO 10993 material” is frequently used within the medical device sector, but it is often misunderstood.
ISO 10993 is a series of standards used to assess the biological safety of medical devices and materials. While materials may have existing biological test data, this does not automatically qualify every finished device for every application
Factors influencing biological evaluation include:
- Whether contact is direct or indirect
- Type of body contact
- Duration of contact
- Manufacturing processes
- Sterilisation methods
- Surface area exposed to the patient
Consequently, biological evaluation should form part of a wider risk-management strategy rather than being treated as a standalone material-selection exercise.
Using materials that already possess supporting biological testing data can often simplify development, but the final cable assembly must still be assessed in its intended application.
Common Biocompatibility Challenges in Medical Cable Assemblies
Even when suitable materials have been selected, several challenges can affect the final product.
Sterilisation-Induced Material Degradation
Some materials can become brittle, discoloured or lose flexibility after repeated sterilisation cycles. This is particularly important for reusable cable assemblies that may undergo hundreds of cleaning or sterilisation cycles during their operational life.
Extractables and Leachables
Certain additives or processing materials may migrate from cable materials over time. These risks should be considered during material selection and verification activities.
Manufacturing Residues
Biocompatibility is not determined solely by raw materials. Processing oils, mould-release agents, cleaning chemicals and other manufacturing residues may also influence the final biological profile of a device.
Traceability Requirements
For regulated medical devices, maintaining material traceability throughout the supply chain is often just as important as initial material selection. Clear documentation supports quality systems, risk management and regulatory submissions.
Sterilisation and Reuse Considerations
Medical cable materials must be compatible with the intended cleaning or sterilisation process throughout the product’s expected life.
Reusable cable assemblies may be exposed repeatedly to:
- Ethylene Oxide (EtO)
- Steam autoclaving
- Gamma irradiation
- Alcohol-based cleaning products
- Chemical disinfectants
Each process places different stresses on material systems and may affect:
- Mechanical properties
- Surface finish
- Adhesion performance
- Flexibility
- Colour stability
Single-use assemblies may not face the same long-term durability requirements, but they must remain safe and reliable throughout manufacturing, sterilisation, transport, storage and end use.
Medical Cable Assembly Expertise at Novara Technologies
At Novara Technologies, we specialise in custom medical cable assemblies and electro-medical device assembly, supporting projects from prototype development through to full-scale manufacture.
We manufacture within our ISO Class 7 cleanroom environment and operate in accordance with ISO 13485 quality-management requirements, helping ensure cleanliness, consistency and full traceability throughout production.
Our engineering teams work with customers to:
- Select suitable materials
- Assess sterilisation compatibility
- Improve manufacturability
- Optimise cable performance
- Reduce development risk
- Support qualification and production activities
By considering biocompatibility, sterilisation and manufacturing requirements from the outset, potential issues can often be identified and addressed before they become costly development challenges.
Frequently Asked Questions
What makes a cable material biocompatible?
A biocompatible material is one that can perform its intended function without causing an unacceptable biological response for the intended application and patient-contact scenario.
Does ISO 10993 approval apply to the complete cable assembly?
Not necessarily. Materials may have supporting ISO 10993 test data, but the finished device must still be assessed based on its intended use, manufacturing processes and patient-contact category.
Can silicone medical cables be autoclaved?
Many silicone materials perform well under repeated autoclave cycles, but suitability depends on the specific formulation and overall cable construction.
Which materials are best for repeated sterilisation?
Silicone, certain TPU grades and specialist medical-grade polymers are commonly used, although the optimum choice depends on the sterilisation method and product requirements.
Why can a material pass biocompatibility testing but still be unsuitable?
Changes in formulation, manufacturing processes, additives, cleaning methods or sterilisation procedures can all influence the biological performance of the finished assembly.
Discuss Your Medical Device Project
Developing a reliable medical cable assembly requires careful consideration of biocompatibility, material performance, sterilisation compatibility and manufacturability.
If you are developing a reusable or single-use medical device and require support with cable assembly design, material selection or manufacturing, contact Novara Technologies to discuss your project with our engineering team.