20.04.2026 — Findings from our first meetings.
Before we continue building the future of biomaterials, we have to address a deceptively simple question: “What is a biomaterial?”.
Over the past two months, we’ve had the opportunity to bring together those who identify themselves as “biomaterials” researchers and stumbled over an odd controversy of its definition.
Traditionally, biomaterials were used in biomedical context, where they are defined by its intended contact with the human body. A biomaterial was a material engineered to interact with tissues for clinical applications, with biocompatibility to a particular tissue as a required property. The International Standards Organisation definition under ISO 10993-1:2025 formalised this definition for regulatory scope and biocompatibility requirements and therefore defines the term to be used for medical function only.
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Material intended to interface with biological systems to evaluate, treat, augment or replace any tissue, organ or function of the body (ISO 10993-1:2025).
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In contrast, the International Union of Pure and Applied Chemistry (IUPAC) have changed their recommended definition in 2012 to be suit a broader scientific audience to encompass beyond the human body to include more of the living world.
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Material exploited in contact with living tissues, organisms, or microorganisms (IUPAC, 2012).
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However, in more recent times, the term “biomaterials” has also been co-opted to imply biological provenance and/or process. Materials that originate and are produced by living systems and can be engineered by materials scientists, biologists, and designers. Another term that could be used here would be “biobased” materials. For instance, Biofabricate and FashionForGood released a 95-page document in 2020 entitled *Understanding “Bio”material Innovations: A Primer for the Fashion Industry,* defining biomaterials as the catch-all term in the perspective of textile innovators particularly for fashion:
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“Biomaterial” is a term used to indicate materials that have non specific biological association. ”Bio-based product” refers to products wholly or partly derived from biomass, such as plants, trees or animals (the biomass can have undergone physical, chemical or biological treatment) (Biofabricate, 2020).
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These terms are not necessarily competitive with each other, but are three overlapping fields that have used one word to define function (use-case in the human body), interaction (with all biological systems), and origin (derivation from living organisms). And this creates friction and confusion between researchers across disciplines.
We believe in acknowledging each of these definitions in the most facile manner and each meeting we are trying to map out the space of biomaterials research without necessarily excluding one particular application or industry (Figure 1).
Biomaterials as a term has been shown to now be commonly used to refer to its use or origin, respectively biomaterials and biobased materials. Though neither of these categorisations implicitly state the performance (e.g. biocompatibility, biodegradability) of the material. Rethink Matters aims to not redefine biomaterials but include materials that could be classified as biomaterials and/or biobased materials into consideration.
Ultimately however, the fields can be united in one clear distinction. “Bio-” does not imply a performance of the material. “Bio-” does not imply biocompatibility, safety, biodegradability, or sustainability. This sector-specific framing of biomaterials can be used ambiguously as a shorthand, but it does not bundle any of these claims that are separately governed and contextualised. This is key analysis that Rethink Matters wants to investigate. This ambiguity in definition is not neutral; it can provoke unsubstantiated claims that risks industries-wide reputations.
Emerging fields can push this semantic ambiguity even further. For example, engineered living materials (ELMs) are beginning to push the concept of “biomaterial” beyond what the regulatory frameworks originally intended. ELMs are not designed to be passive materials. They incorporate living cells in a material that can sense, respond, grow, and adapt over time. A bacterial biofilm that self-repairs its structure or delivers therapeutic payloads is not simply interacting with biology. It is biology, in all its glorious complexity that we have previously aimed to mimic.
This is even more pronounced with mammalian systems with research into stem-cell derived tissues and organoids, as the “material” is biochemically indistinguishable from living tissue itself. These constructs actively participate in physiological processes like signaling, remodeling, and integration with their intended host. The scaffold to seed with mammalian cells might still be called a biomaterial, but their evaluation will often be under advanced therapeutics or biologics frameworks. This shift also changes how we think about biocompatibility as a fixed property. What implications of testing biocompatibility if these hybrid living materials evolve over time? What we are observing is not just a shift in materials science, but a shift in ontology. The term “biomaterial,” originally developed to describe passive substances interacting with biology, is now being applied to systems where biology itself is the material.