In diagnostics and biosensing, materials are frequently described as biocompatible. The term appears in datasheets, publications and supplier documentation across electrode substrates, coatings, inks and polymers.
However, within regulated medical and diagnostic applications, biocompatibility is not a single test result or a material property in isolation. Under ISO 10993, it is the conclusion of a structured biological evaluation, specific to how a material is used, processed and brought into contact with the body.
This distinction is subtle but important, and it directly affects how much confidence manufacturers can place in a material when progressing toward clinical or regulated use.
ISO 10993-1 defines biocompatibility assessment as part of a risk management process, where biological safety is evaluated in the context of:
The standard does not define biocompatibility as a universal label that transfers automatically between applications. Evidence must be relevant to the intended use of the final device.
In practice, this means that the biological safety profile of a material used in a benchtop assay, a disposable cartridge and a wearable diagnostic patch may require very different supporting evidence even if the base material is nominally the same.
Many advanced materials used in biosensors are supported by partial biological evidence. This may include an in vitro cytotoxicity test conducted under ISO 10993-5, a reference to previously published academic literature or biological data generated for a different contact scenario
Each of these data types can be valuable during early research and development. However, on their own, they rarely constitute a complete biological evaluation for regulated diagnostics.
For example, ISO 10993-5 cytotoxicity testing assesses whether a material extract causes acute cell damage under defined conditions. It does not address other biological endpoints that may become relevant depending on exposure, such as irritation, sensitisation, systemic toxicity or local tissue response.
Similarly, literature data is often generated outside Good Laboratory Practice (GLP) environments and may not reflect the final manufacturing state, surface chemistry or extraction conditions of a commercial material.
As a result, materials described as “biocompatible” may still require substantial additional testing when a manufacturer begins preparing a Biological Evaluation Report (BER) or regulatory submission.
A robust ISO 10993-aligned programme typically integrates multiple elements rather than relying on a single test result. Depending on the intended use, this may include:
This approach does not eliminate the need for device-specific evaluation, but it significantly reduces uncertainty at the material level.
When biocompatibility is treated as a design requirement rather than a validation step, evaluation begins early and progresses in parallel with factors like performance optimisation and scalability. Instead of relying on minimal or indirect evidence, a material developed in this way is supported by a structured biological safety programme aligned to clinically relevant conditions of use.
Over an extended development period, such a programme would typically be conducted at accredited laboratories under OECD Good Laboratory Practice (GLP). Based on ISO 10993 and the intended contact type and duration, this would include:
For biosensor developers, material choice influences more than electrochemical performance. It directly affects the scope of biological evaluation required later, the complexity of the BER, the likelihood of repeat testing and confidence during regulatory review. By selecting a material with an established, GLP-grade biological safety profile across multiple ISO 10993 endpoints, manufacturers can reduce biological uncertainty early.
“Biocompatible” is a useful term, but in regulated diagnostics it only has meaning when supported by relevant, standards-aligned evidence. Confidence comes from understanding how thoroughly biological safety has been evaluated and under what conditions.
This is the basis on which Gii, our innovative carbon nanomaterial, has been developed. Its biological safety profile is supported by an extensive ISO 10993-aligned testing programme carried out over 18 months at accredited laboratories under OECD Good Laboratory Practice. The programme spans nine formal studies, covering cytotoxicity, irritation and sensitisation, systemic toxicity, implantation, extractables and leachables analysis and toxicological risk assessment.
Across all endpoints assessed, no adverse biological effects were observed. For diagnostic manufacturers, this depth of evidence provides confidence that material-level biocompatibility has already been addressed in a way that is relevant to clinical use, reducing uncertainty as devices move toward regulatory evaluation. To find out more about Gii and the future of biosensing, download our guide below.