Biomaterials in ubiquitous computing

The space of ubiquitous computing in HCI aims to embed computing capabilities into everyday materials and objects, making technology invisible and accessible in the background. This often looks like smart home devices (e.g., speakers, refrigerators), wearable technologies (e.g., watches, glasses) and smartphones. Bio-HCI has, in turn, been exploring how biomaterials can integrate within these interactive everyday objects.

Current research has primarily revolved around how biomaterials can seamlessly integrate with traditional electronic components (Genç et al. Reference Genç, Launne and Häkkilä2022; Alistar et al. Reference Alistar, Al-Naimi, Mohammadi, David, Tung and Lazaro Vasquez2024; Luo et al. Reference Luo, Gu, Qin, Wang and Yao2020), as well as how biomaterials can be used to make new biodegradable electronic components (Lu and Lopes Reference Lu and Lopes2022; Song and Paulos Reference Song and Paulos2023; Zhu et al. Reference Zhu, Winagle and Kao2024). Some notable examples include a video game controller that was grown from microbial cellulose, and embedded with LEDs, touch sensors, buttons and a microcontroller (Nicolae et al. Reference Nicolae, Roussel, Koelle, Huron, Steimle and Teyssier2023), a heater that was made from leaf skeletons coated in chitosan and silver nanowires (Song et al. Reference Song, Maheshwari, MGallo, Danielescu and Paulos2022), and a breadboard that was grown from mycelium and laser cut to allow the connection of LEDs, batteries, wires and a potentiometer (Lazaro Vasquez Reference Lazaro Vasquez2019). More exploratory work has developed new biomaterials like algae-based bioplastics (Koelle et al. Reference Koelle, Nicolae, Nittala, Teyssier and Steimle2022; Bell et al. Reference Bell, Naimi, McQuaid and Alistar2022) and gelatin-based biofoams (Lazaro Vasquez et al. Reference Lazaro Vasquez, Ofer, Wu, West, Alistar and Devendorf2022) to integrate with conductive materials like activated charcoal powder and stainless steel fibers, thus enabling these biomaterials to act as sensors that can become a part of a larger interactive system.

These works begin to demonstrate a future of sustainable smart devices, interactive everyday objects that are grown from renewable biological sources and biodegrade naturally in the environment when disposed of. While the ultimate goal is to create entirely circular interactive technologies, current efforts that integrate non-biodegradable components (e.g., electronics) focus on harvesting and reusing these components, while the rest of the object biodegrades. The inherent growth and decay of these sustainable biomaterials challenge existing assumptions regarding the durability, scalability, temporality and invisibility of ubiquitous computing, opening new relations, interactions and esthetic appreciations of technology.

Biomaterials in digital fabrication

The space of digital fabrication within HCI addresses the workflow of transforming digital data into tangible objects. In digital fabrication, a digital model is created and translated into code that directly controls manufacturing machines. For example, laser cutting and computer numerical control (CNC) routing subtractively removes material to achieve a given form, while laminated object manufacturing and 3D printing additively build up layers of material to achieve the given form.

3D printing has notably risen as a popular method for digital fabrication given its accessibility, affordability, versatility and capabilities (Mellis et al. Reference Mellis, Follmer, Hartmann, Buechley and Gross2013). However, many 3D printing workflows suffer from a reliance on plastics and their corresponding production of renewable print waste. As such, recent Bio-HCI efforts have focused on developing new biomaterials for 3D printing. One of the most widely used biomaterials for 3D printing, Polylactic acid (PLA), is a thermoplastic polyester derived from fermented plant starches, such as corn and cassava. While considered sustainable in comparison to petroleum-based plastic filaments, PLA cannot readily biodegrade in the natural environment, instead requiring industrial composting systems (Kolstad et al. Reference Kolstad, Vink, Wilde and Debeer2012). PLA has further been mixed with other ingredients like wood (Yubo Tao et al. Reference Tao, Wang, Li, Li and Shi2017) and cocoa shells (Tran et al. Reference Tran, Bayer, Heredia-Guerrero, Frugone, Lagomarsino, Maggio and Athanassiou2017); however, the biodegradability of these hybrid PLA filaments has not been tested.

To ameliorate this issue, recent research proposed switching from 3D printing biomaterial filaments (like PLA) to biomaterial pastes instead of filaments. This is because biomaterial pastes can be more easily designed to readily biodegrade in the environment and require less energy to be extruded from a 3D printer (Faludi et al. Reference Faludi, Van Sice, Shi, Bower and Brooks2019). The paste extrusion method for 3D printing – also known as Direct-Write printing or Robocasting (Peng et al. Reference Peng, Zhang and Ding2018) – has led to the development of radically sustainable biomaterials made from spent coffee grounds (Rivera et al. Reference Rivera, Sandra Bae and Hudson2023), mussel shells (Sauerwein and Doubrovski Reference Sauerwein and Doubrovski2018), oyster shells (Monsieur and Andersen Reference Monsieur and Andersen2024), sawdust (Buechley and Ta Reference Buechley and Ta2023) and corn flour (Soh et al. Reference Soh, Chew, Saeidi, Javadian, Hebel and Le Ferrand2020). These new biomaterials introduce new constraints regarding their unique properties and behaviors that contrast traditional digital fabrication processes and materials like plastic or metal. Accordingly, this shift towards biomaterials not only enables the digital fabrication of more circular objects, but also encourages a convergence of biological and digital workflows, opening up new practices of fabrication that revolve around different temporalities and agencies of machines and materials.

Biomaterials in dynamic interfaces

Lastly, the space of dynamic interfaces within HCI broadly refers to user interfaces that can adjust in real-time in response to user input and context. Inherently responsive, reactive, or otherwise expressive materials are key to enabling dynamic interfaces. Such materials can change color or shape in response to stimuli like temperature, ultraviolet light, moisture and movement. In terms of Bio-HCI, biomaterials such as algae-based bioplastics and gelatin-based biofoams have been integrated with color-changing pigments to respond to changes in temperature, ultraviolet light and pH (Bell et al. Reference Bell, Naimi, McQuaid and Alistar2022; Lazaro Vasquez et al. Reference Lazaro Vasquez, Ofer, Wu, West, Alistar and Devendorf2022; Søndergaard and Campo Woytuk Reference Søndergaard and Campo Woytuk2023), while flour-based doughs and wood-based composites have been designed to change shape in response to water exposure (Ye Tao et al. Reference Tao, Do, Yang, Lee, Wang, Mondoa, Cui, Wang and Yao2019; Luo et al. Reference Luo, Gu, Qin, Wang and Yao2020; Lu et al. Reference Lu, Yi, Gan, Huang, Zhang, Yang, Shen and Yao2024).

Alternatively, living organisms used as biomaterials have the ability to naturally react to such stimuli. These dynamic living interfaces (Merritt et al. Reference Merritt, Hamidi, Alistar and DeMenezes2020) essentially leverage organisms as “computers” to naturally process input information and display a response in return. For example, Infotropism leverages plants’ natural tendency to move to face light to display information (Holstius et al. Reference Holstius, Kembel, Hurst, Wan and Forlizzi2004), while the Plant-Driven Actuators utilize plants to literally make robots grow, age and decay (Hu et al. Reference Hu, Lu, Scinto-Madonich, Pineros, Lopes and Hoffman2024). Microorganisms particularly present many possibilities in this space, with Flavorium demonstrating how flavobacteria shifts color in response to changes in temperature (Groutars et al. Reference Groutars, Risseeuw, Ingham, Hamidjaja, Elkhuizen, Pont and Karana2022), Algae Alight showcasing dinoflagellates releasing a bright blue bioluminescence in response physical movements (Breed et al. Reference Breed, van der Putten and Barati2024), and BioLogic utilizing bacterial natto cells embedded within textiles to change shape in response to humidity (Yao et al. Reference Yao, Ou, Cheng, Steiner, Wang, Wang and Ishii2015).

Unlike biomaterials for ubiquitous computing, biomaterials for dynamic interfaces use the inherent responsiveness or livingness of biomaterials to create interactive technologies. In this space, we can envision future interfaces that are not actuated by traditional electronics, but instead by biomaterials that naturally respond to biological inputs. While this presents a more sustainable alternative, it also raises ethical questions about what it might mean to care for the biomaterials embedded within our technologies.

SCOBY breastplate

The SCOBY Breastplate project follows the design of an interactive wearable grown from scoby (Bell et al. Reference Bell, Ramsahoye, Coffie, Tung and Alistar2023a). Scoby is a symbiotic culture of bacteria and yeast that grows in a liquid kombucha culture. Over time, the bacteria and yeast form a layer of cellulose-based biofilm at the top of the liquid. It takes approximately 1 month for a scoby biofilm to grow to a thickness of approximately 1 cm, as can be seen in Figure 2.

Figure 2.

Scoby is a symbiotic culture of bacteria and yeast that grows a cellulose-based biofilm at the air-liquid interface of kombucha over the course of several weeks.

To create the breastplate, we grew scoby in a large container, then harvested the biofilm, cut it to our desired size and shape, and dried it around a mannequin. We took advantage of the scoby biofilm’s ability to adhere to itself – when we added a new layer of biofilm to the mannequin, it adhered to the layer of biofilm beneath it – allowing us to build up layers to create the breastplate. We utilized a total of 4 biofilms, each one being harvested after about 3 weeks of growth, as shown in Figure 3. This meant that the breastplate was slowly designed and fabricated at the rate of the scoby biofilm’s growth.

Figure 3.

The SCOBY Breastplate was slowly designed and fabricated in layers at the rate of the scoby biofilm’s growth.

The layering technique was used to seamlessly embed a strand of LEDs and a custom capacitive touch sensor, which were connected to a microcontroller and battery as annotated in Figure 4. The capacitive touch sensor is particularly notable as it was made from a layer of scoby biofilm coated in activated charcoal. When the sensor is touched, the programmed microcontroller activates the LEDs. The brightness and length of LED illumination correspond to the length and pressure of touch: a short, light touch results in a brief, dim glow, while a long, firm touch results in a lingering, bright glow.

Figure 4.

The SCOBY Breastplate leverages scoby’s ability to self-adhere to seamlessly embedded LEDs and a custom capacitive touch sensor made from scoby biofilm coated in activated charcoal.

When the SCOBY Breastplate is no longer wanted or needed, it can be disposed of in the environment. The test in Figure 5 shows that the scoby biofilm takes 30 days to biodegrade approximately 96% in a microbial-rich soil, while our custom scoby capacitive touch sensor (i.e., the scoby biofilm coated in activated charcoal) biodegrades approximately 84%. While the custom scoby sensor can biodegrade, the other traditional electronic components embedded within the breastplate – the LEDs, microcontroller and battery – must be removed before disposal. We encourage these components to be reused for other projects.

Figure 5.

Biodegradation based on the mass-loss of scoby and the scoby sensor over time in a soil environment.

The SCOBY Breastplate showcases how biomaterials and electronics can be seamlessly integrated to create an esthetic, interactive and sustainable wearable. It not only exemplifies how traditional electronics such as LEDs and microcontrollers can be embedded within the scoby biofilm, but it also highlights how the scoby biofilm itself can be used to make a new biodegradable electronic component (e.g., the capacitive touch sensor). In contrast to typical electronic prototyping practices in HCI that trend toward a “move fast and break things” mentality, the SCOBY Breastplate demonstrates carefully designing a computational system at the rate of another living organism. The relative slowness of the scoby biofilm’s growth encouraged a more thoughtful and intentional practice of embedding and assembling the electrical system. In this way, the SCOBY Breastplate evokes new possibilities for designing future sustainable ubiquitous computational devices and systems, where we grow electronic components that can then biodegrade in the environment.

B10-PR1NT

The B10-PR1NT project revolves around the development of an eggshell-based biomaterial for paste extrusion 3D printing (Bell et al. Reference Bell, Friedman-Gerlicz, Urenda and Buechley2025). We intentionally designed the eggshell biomaterial to be circular, considering the entire life cycle – as shown in Figure 6 – from sourcing eggshells in our local community through developing a recipe, 3D printing objects, deploying the objects back in our community, and then recycling the biomaterial for immediate reuse or biodegrading objects to return nutrients to the environment.

Figure 6.

A circular design process for the eggshell biomaterial.

We began by collecting eggshells from our personal food waste, from friends and family who own chickens, and from local restaurant waste. To make a paste, we ground the eggshells into a fine powder that we combined with xanthan gum, methylcellulose and water. We iterated through several different ratios of these four ingredients to identify a recipe that could successfully extrude through our printer and build up in stable layers. Figure 7 includes only four of 10+ iterations, where we kept the amount of eggshells and water the same, but varied the amount of xanthan gum and methylcellulose to produce a recipe that had the appropriate rheological material properties for printing, resulting in functional and esthetic objects. This required significant testing, taking into account how the machine applied force to the biomaterial for extrusion and how the rheological properties of the biomaterial responded to the applied force. Iteration 4 indicates our final recipe suited to our printer.

Figure 7.

Several recipes made from eggshell powder (eggs), xanthan gum (xg), methylcellulose (mc) and water were tested to identify a biomaterial that could easily extrude through our printer and build up in stable layers.

To print objects from our eggshell biomaterial, we first modeled our desired object in Rhino and Grasshopper. We then used WeaveSlicer, an open-source software designed for 3D printing in paste-like materials (Friedman-Gerlicz et al. Reference Friedman-Gerlicz, Gelosi, Bell and Buechley2024), to slice our model and produce a gcode file for the printer to read. We uploaded the gcode to our printer – the Eazao Zero. The Eazao Zero is a low-cost, desktop printer that extrudes paste-like materials (instead of filament) in layers to build up objects. Annotated in Figure 8, the printer uses a motor to push the eggshell biomaterial through the print tube and flexible hose into the extruder head and nozzle. We also employed a custom heater that sits around the extruder nozzle, made from two fans and nichrome heating wire, to further improve layer stability during printing. We print objects onto a board that can be easily removed from the print bed. Once removed from the print bed, objects are dried fully before being deployed.

Figure 8.

Paste extrusion 3D printer used for the eggshell biomaterial.

We specifically designed and deployed eggshell objects that encourage circularity. For example, we created a hen feeder, a shallow bowl printed from eggshells for hens to eat from. Hens often suffer from calcium deficiency caused by laying eggs. As eggshells are often used as a Do-It-Yourself (DIY) calcium supplement for hens, the feeder is intended to be consumed. We envision the hens slowly consuming the feeder as they peck away at the rest of their food, as demonstrated in Figure 9. If not consumed by the hens, the feeder can assimilate into the surrounding environment through biodegradation – which we found takes about 25 days in soil. Biodegradation of the nutrient-rich feeder, in turn, promotes the growth of plants such as alfalfa, oats, or millet, which the hens can then eventually eat.

Figure 9.

Hen feeder 3D printed from the eggshell biomaterial. We envision the feeder being consumed by the hens as a calcium supplement or biodegrading in the environment.

B10-PR1NT demonstrates how new biomaterials can be developed with both biological and digital processes in mind. It highlights how to intentionally design a circular biomaterial from a locally available waste stream (eggshells) and other bio-based ingredients to transform the eggshells into a paste. The selection of ingredients ensures that the biomaterial can ultimately biodegrade in the environment when disposed of. The eggshell biomaterial is also designed to be recycled – print waste or unwanted objects can be ground into a powder and rehydrated with water to be re-printed. In this way, the eggshell biomaterial presents a circular digital workflow that drastically contrasts linear workflows designed for traditionally “technological” materials, such as plastics, metals and glass, which are not readily biodegradable nor easily recyclable. Beyond circularity, the properties of the eggshell biomaterial were designed to suit the behavior of the 3D printer, while also inspiring the design of new software and hardware tools for 3D printing. As such, the eggshell biomaterial exemplifies how digital fabrication can inform and support biomaterial development and how biomaterials can extend the creative capabilities of digital fabrication in return. This opens up several new opportunities for designing new digital fabrication workflows that align with the circularity and other unique properties of biomaterials.

$\mu $ Me

The $\mu $ Me project explores using the personal microbiome to create living, dynamic interfaces (Bell et al. Reference Bell, Ramsahoye, Coffie, Tung and Alistar2023b). The microbiome refers to a community of microorganisms – microscopic bacteria and yeast – that grow in any given environment. $\mu $ Me specifically focuses on the human skin microbiome as a living biomaterial that can reveal information about the body and the body’s interactions with the surrounding environment. We began this exploration by growing skin microbiome samples in petri dishes that contain an agar-based growth media. As shown in Figure 10, it takes approximately a week of growth for the microorganisms present in a microbiome sample to become visible to the naked eye and express their full range of colors.

Figure 10.

Microbiome sample growing on a petri dish. Over the course of a week, it becomes visible and expresses its full range of colors.

The types of microorganisms present in each microbiome sample are unique to each body (e.g., each person has a different microbiome), while also reflecting external environmental factors that the body engages with (e.g., temperatures, surfaces and other people can impact the microbiome). To begin to visualize these microbial interactions, we transformed our microbiome samples into a palette of responsive, living dyes that reflect the body, as shown in Figure 11. To create this palette, we isolated specific colorful bacterial colonies from our microbiome samples and subcultured them in new petri dishes. We then collected the isolated bacteria in centrifuge tubes, added distilled water and then used a vortex mixer to obtain a homogeneous bacterial dye. We used this method to obtain a variety of colors that reflect author 1’s skin microbiome. We used this personal palette to dye textiles, thus enabling the creation of wearable interfaces that utilize the microbiome as a material that can sense and display information regarding our body and our bodily interactions in real-time. These living microbial interfaces contrast typical digital displays in that the rate of response and display is inherently ephemeral as the microbes continue to grow and die.

Figure 11.

A palette of living bacterial dyes was derived from microbiome samples by isolating and subculturing bacterial colonies, harvesting the bacteria and mixing the bacteria with water to reach a homogeneous dye.

One of our resulting $\mu $ Me interfaces was a wearable pendant that changes color in response to temperature. The pendant consists of a layered system that sits against the body, schematically shown in Figure 12. The bottom layer is a textile-based heater made from felt and heating wire that is connected to a battery. On top of the heater sits a custom petri dish made for 6 circular pools that are filled with the agar-based growth media. On top of the agar, sits 6 corresponding circles of cotton textile. The textile was then coated in differing amounts of one of our bacterial dyes derived from Serratia marcescens, a bacteria present in our microbiome. The system is designed to provide the living bacteria with an appropriate environment (e.g., warmth and nutrients) to grow, and thus dynamically react to inputs like temperature change.

Figure 12.

Schematic of the layered pendant system that consists of a textile heater situated beneath a custom petri dish filled with agar and topped with cotton dyed with bacteria.

After one day of growth at room temperature (22 C), the bacteria dyed the cotton a light pink color. On the second day, we turned on the textile heater positioned beneath the dish (30 C), resulting in the bacteria expressing a darker pink color in response to the raised temperature. Because the heater and custom petri dish are different sizes and geometries, only select areas of the pendant changed color, reflecting where the heater was placed underneath the petri dish, as seen in Figure 13. By controlling the heater, we showcase how the pendant can react in real-time to changes in temperature by leveraging the inherent responsiveness of the living Serratia marcescens dye.

Figure 13.

The interactive pendant changes color from light pink to dark pink as the bacterial dye responds to the rising temperature of the heater.

${{\mu }}$ Me demonstrates the power of leveraging living microorganisms as natural “computers” to create dynamic interfaces. In contrast to a digital system – for example, LEDs that change color in response to temperature sensor data – the bacteria both senses temperature change and displays a different color in response. While current digital interfaces reveal information seemingly instantaneously, the $\mu $ Me interface functions at the temporal rate of the microbiome, responding at a comparatively slow rate. The information revealed is also ephemeral, as the bacteria continue to grow, change and die. As such, the functionality of $\mu $ Me interfaces depends on the health of the growing microbiome samples, which must be kept alive. These living dynamic interfaces call for new care-taking measures that traditional electronic systems do not require, such as integrating nutrients (like the agar-based growth media) and maintaining appropriate environmental conditions (like temperature) within a system. By leveraging living organisms within dynamic interfaces, we see an opportunity for developing more caring and conscious modes of engaging with technology.

Control and agency

Within the field of HCI, as well as across broader design and engineering disciplines, there is an assumption that the human maker has ultimate control over the material to achieve a given design objective. For example, controlling fabric through cutting and sewing to make an item of clothing, or controlling code through programming to build a website.

When working with biomaterials, however, control is not entirely in the hands of the human maker. This is most noticeable in the SCOBY Breastplate and $\mu $ Me projects, when working directly with living biomaterials that have agency through their livingness (Karana et al. Reference Karana, Barati and Giaccardi2020). For example, we controlled the temperature of the interactive pendant system, but it was the bacterial dye itself that responded to this environmental change and expressed a different color. Similarly, while we controlled the size and shape of scoby to make the breastplate, the scoby naturally had uneven color and inconsistent thickness. These unpredictabilities inherently call attention to the agency of the non-human organism that is being utilized as a biomaterial. This recognition of non-human living organisms as active agents in the design process echoes other Bio-HCI works that build interfaces around dinoflagellates Ofer et al. Reference Ofer, Bell and Alistar2021; Barati et al. Reference Barati, Karana, Pont and van Dortmont2021), flavobacteria (Groutars et al. Reference Groutars, Risseeuw, Ingham, Hamidjaja, Elkhuizen, Pont and Karana2022; Kim et al. Reference Kim, Risseeuw, Groutars and Karana2023) and mold (Kim et al. Reference Kim, Thomas, van Dierendonck and Poslad2018; Riggs et al. Reference Riggs, Nitsche and Howell2025). The shared sense of agency is evident in these cases, where unpredictable and uncontrollable living biomaterials necessitate direct correspondence with the human designer, thereby challenging the typically controlled and expected interactions with technology.

In contrast, the eggshell biomaterial was the relatively controllable, especially given that we intentionally developed a recipe that could be reliably 3D printed with our machine. However, this case introduces the agency of the machine (Devendorf and Ryokai Reference Devendorf and Ryokai2015). While we controlled the material through the recipe and controlled the printer through code, unpredictable outcomes still upended our notion of control – printer hiccups, code blips and biomaterial inconsistencies caused unexpected imperfections in our digitally fabricated objects that showcase the agency of both biological and digital factors in the design process. The entangled agencies of biomaterials and machines has been explored in other projects, such as Weaving Stories, where the creative capacity of wool and a digital jacquard loom are brought to the forefront of the design process as agentic constituents, demonstrating a more-than-human approach to design (Oogjes and Wakkary Reference Oogjes and Wakkary2022). We note that the complex agentic relationships between humans, biomaterials, machines and code in these contexts pose a unique set of challenges and questions that require further exploration.

By taking a biodesign approach that is rooted in a more-than-human design philosophy (Wakkary Reference Wakkary2021) to these HCI projects, we recognize that the biomaterial itself, as well as our digital materials and tools, have a distinct agency in the design process. The resulting artifacts (e.g., the breastplate, the hen feeder, the pendant) reflect shared control and agency. Given current hierarchical perspectives of agency and control in design and engineering, we believe the emerging area of Bio-HCI is well-positioned to open up new opportunities and possibilities for (re)negotiating the relationships between humans, materials and tools in the design process by introducing biological systems.

Temporal rates and rhythms

One of the most notable impacts of biomaterials’ agency on the design process is the unique temporalities that they carry. Unlike conventional materials that are often used and fabricated at a human-dictated pace, biomaterials require designers to work in alignment with their natural growth cycles (Lazaro Vasquez et al. Reference Lazaro Vasquez, Wang and Vega2020). For example, the SCOBY Breastplate was gradually designed at the pace of the scoby biofilm’s growth. This biodesign approach, dictated by biological processes like the growth of an organism, challenges typical human-centered temporalities of design in HCI, which often prioritize speed and efficiency. By respecting the inherent temporal rates and rhythms of biomaterials, designers can shift their perspective, treating biomaterials like scoby as a valuable and precious resource that should be used with intentionality. This slow intentionality caused by biomaterials can then potentially extend to other materials used in the design process, like electronic components, which we carefully considered when integrating with the scoby biomaterial.

Temporalities also go beyond fabrication, influencing the rate of interaction. Digital user interfaces that are pervasive in our everyday lives, respond seemingly immediately, feeding into interactions that provide instant gratification. However, a living user interface like $\mu $ Me disrupts this expectation by operating at the temporal rate of the live microorganisms. $\mu $ Me instead changes color in response to a new temperature input relatively slowly (e.g., 24 hours). This interaction is shaped by the biological rates of the living biomaterials. Accordingly, $\mu $ Me interfaces are always changing, and thus ephemeral (Döring et al. Reference Döring, Sylvester and Schmidt2013). The ephemerality of living biomaterials has been of particular interest in other Bio-HCI works such as Mold Sounds, an artifact that produces sounds that change over time as mold grows and interacts with the embedded conductive components (Riggs et al. Reference Riggs, Nitsche and Howell2025), Mould Rush, a game that is played at the growth rate of various microorganisms (Kim et al. Reference Kim, Thomas, van Dierendonck and Poslad2018), the Cyano-chromic Interface, a monochromatic display that changes color gradually to indicate that cyanobacterial photosynthesis is occurring, thus bringing deeper awareness to the organisms livingness (Zhou et al. Reference Zhou, Kim, Doubrovski, Martins, Giaccardi and Karana2023). These works challenge the dominant paradigm of technological temporalities and encourages users to engage with interfaces that constantly evolve over time.

On top of the temporal rates dictated by growth, biomaterials also introduce new considerations regarding their temporality of use and decomposition. The eggshell biomaterial especially demonstrates this, as it was intentionally designed to biodegrade rapidly in the environment to return nutrients to the Earth. Beyond biodegradation (Song et al. Reference Song, Maheshwari, MGallo, Danielescu and Paulos2022; Søndergaard and Campo Woytuk Reference Søndergaard and Campo Woytuk2023), other modes of degradation such as dissolving (Lazaro Vasquez et al. Reference Lazaro Vasquez, Gabriel, Friske, Wu, De Koninck, Devendorf and Alistar2023; Rivera et al. Reference Rivera, Sandra Bae and Hudson2023) and disassembling (Song and Paulos Reference Song and Paulos2021) highlight the temporality of degradation in Bio-HCI. The inherently transitory quality of biomaterials is essential for the development of fully circular systems that align with larger ecological cycles that distribute nutrients. By embracing the rhythmic temporality of decay and renewal, there is an opportunity to work towards a more ecologically conscious approach to materiality, one that acknowledges the impermanence of objects and the necessity of their reintegration into the ecosystem.

Circularity and sustainability

Stemming from the natural temporalities of biomaterials, a biodesign approach requires thinking in terms of biological life cycles – acknowledging the interconnected processes of growth, decay and renewal. This mindset contradicts the linear model of production and disposal often associated with modern design and engineering in capitalist contexts. The shift towards designing with biomaterials and biological processes presents an opportunity to develop technologies that align with natural life cycles, fostering circularity (Pollini and Jimenez Reference Pollini and Jimenez2022).

While the eggshell biomaterial used in B10-PR1NT clearly demonstrates this circularity through both its biodegradability and recyclability, the SCOBY Breastplate is a more complex case. The scoby biofilm rapidly biodegrades in soil, but the traditional electronic components embedded within it (e.g., the LEDs, microcontroller and battery) cannot. The integration of such components within biomaterials demands further consideration (Lazaro Vasquez Reference Lazaro Vasquez2019; Genç et al. Reference Genç, Launne and Häkkilä2022), not only in terms of how these electronic components can be harvested and reused to prolong the disposal of e-waste (Lu et al. Reference Lu, Desta, Wu, Nith, Passananti and Lopes2023), but also how these electronic components can ultimately be redesigned so that they can biodegrade. This direction of biomaterial-based electronics highlights an exciting path for Bio-HCI, which has developed biodegradable heaters (Song et al. Reference Song, Maheshwari, MGallo, Danielescu and Paulos2022), sensors (Koelle et al. Reference Koelle, Nicolae, Nittala, Teyssier and Steimle2022; Lazaro Vasquez et al. Reference Lazaro Vasquez, Ofer, Wu, West, Alistar and Devendorf2022), optical fiber (Guridi et al. Reference Guridi, Pouta, Hokkanen and Jaiswal2023), electrical energy storage (Song and Paulos Reference Song and Paulos2023), wires (Lu and Lopes Reference Lu and Lopes2022), actuators (Luo et al. Reference Luo, Gu, Qin, Wang and Yao2020; Yao et al. Reference Yao, Ou, Cheng, Steiner, Wang, Wang and Ishii2015) and breadboards Lazaro Vasquez (Reference Lazaro Vasquez2019).

Beyond the circular methods of disposal that are encouraged in Bio-HCI prototyping processes (Lazaro Vasquez et al. Reference Lazaro Vasquez, Wang and Vega2020), factors such as energy consumption, the sourcing and shipment of materials and tools, and the social, economic and cultural impacts of materials and technologies are critical for a more holistically sustainable design practice (Blevis Reference Blevis2007). For example, in the B10-PR1NT project, we recognize the power consumption of 3D printing as a digital fabrication method, but also understand that 3D printing with a sustainable paste-like biomaterial can significantly reduces power consumption (Faludi et al. Reference Faludi, Van Sice, Shi, Bower and Brooks2019). We also consider the locality of sourcing eggshells from our immediate, socioculturally situated community, and print objects that can be deployed back in our community. These socio-cultural aspects of Bio-HCI are also explored in the context of community-oriented Bio-HCI projects such as Biomenstrual, which brought attention to the environmental sustainability of menstrual products by designing biodegradable alternatives (Søndergaard and Campo Woytuk Reference Søndergaard and Campo Woytuk2023) and SeaFoam, which drew from the cultural significance of local seaweed ecologies when developing an algae-based bioplastic (Soares da Costa et al. Reference Soares da Costa, Simoes, Duarte and Nisi2025).

While circularity and sustainability is broadly embraced as a key motivator and contribution of many Bio-HCI works, we hope to see deeper and more nuanced understandings of sustainability in the future. By designing with material, technological and biological life cycles in mind, as well as with an understanding of how these cycles impact broader communities and ecologies, we can move toward a more regenerative practice that aligns interactive technology innovation with the principles of environmental and social sustainability.

Ethics and care

Rethinking our relationship with technology through the lens of care, for both the specific biomaterials used in design and the broader environment, offers a shift away from the conventional disposable mindset that dominates digital technologies, towards a more sustainable mindset. Part of this is due to the unique agencies and temporalities of biomaterials, which demand new relationships of understanding, respect and care from users.

This is most clear with living biomaterials, which carry ethical requirements in terms of ensuring the health of the organism – for example, growing, feeding and maintaining the health of the scoby biofilm culture or the microbiome samples. While this relationship between the human user and the living biomaterial may be viewed as mere maintenance, many prolonged interactions of ensuring health (e.g., feeding and facilitating ideal growing conditions) can develop deeper relationships of care. These interactions of care are noted in several Bio-HCI works. For example, LivingLoom (Zhu et al. Reference Zhu, Chang, Zhao and Kao2025) and FloraWear (Nam et al. Reference Nam, Campbell, Webb and Harmon2023) embed plants into wearables, encouraging a more embodied care-taking practice with the plants. Care is also emphasized when designing interactions with dinoflagellates, bioluminescent algae that require kinetic movement from humans (Ofer et al. Reference Ofer, Bell and Alistar2021) or machines (Breed et al. Reference Breed, van der Putten and Barati2024) to oxygenate the water in non-natural environments (i.e., indoor lab or studio spaces), resulting in a reciprocal blue glow from the dinoflagellates.

When biomaterials are combined with interactive technologies, we envision this ethos of care extending to the entangled digital components. Many electronics are designed for obsolescence, with little consideration for their longevity or ethical implications. By treating these technologies as something to be cared for rather than discarded, we could cultivate more sustainable interactions, designing systems that encourage repair, adaptation and long-term stewardship (Gegenbauer and Huang Reference Gegenbauer and Huang2012). This idea is taken a step further in the Slime Mold Smartwatch, where the digital functionality of the watch is dependent on the continued well-being of a living slime mold “wire,” resulting in care being a daily interaction the user has with the slime mold and the digital system the slime mold is integrated within (Lu and Lopes Reference Lu and Lopes2022). Similarly, caring for the Plant-Driven Actuators is leveraged to develop relationships of care towards the robots the plants are embedded within (Hu et al. Reference Hu, Lu, Scinto-Madonich, Pineros, Lopes and Hoffman2024).

By embracing care-based practices, we can foster more intimate, reciprocal relationships with both biological and digital technologies, creating systems that are not only functional, but also responsible. These relationships of care extend beyond ethical interactions, facilitating an attunement to the well-being of other living beings and a broader mindset of care for the broader environment.