Wired for Growth

As a nascent area within the field of human-computer interaction (HCI), Growing Design is still largely unexplored. This technique seeks to fabricate materials from living organisms through natural processes like fermentation, biomineralization, and cellular division. By harnessing the power of biology and merging it with cutting-edge technology, Growing Design holds the promise of revolutionizing many areas beyond HCI, ranging from architecture to sustainable fashion. Imagine buildings that self-repair, garments that grow and adapt to our bodies, or even bioengineered furniture that matures and evolves with time. As researchers delve deeper into this uncharted territory, the possibilities for innovation and sustainable solutions are seemingly boundless.

There is a desire within HCI to leverage self-reproduction, and other aspects of Growing Design, to create new types of sustainable materials with interesting properties, like the ability to create seamless connections. However, integrating electronics into these materials is very challenging, and that poses a significant problem for HCI, where electronic components are essential. As you might expect, electronics and biological organisms have very different ideas about what an ideal environment looks like. Many organisms popular in Growing Design, for example, require damp, acidic conditions that would corrode electronic components.

Bacterial cellulose, an organic material produced by certain types of bacteria, has stood out as a promising material for Growing Design applications. It has proven itself to be strong, relatively simple to produce, and highly versatile. But the conditions required for producing this coveted substance are incompatible with the integration of electronics. Or at least that was the case in the past, but a team led by researchers at Saarland University is working to make it possible.

In their recent work, the researchers explored the development of what they call Biohybrid Devices. The work focused on developing fabrication protocols that leverage the bio-based bacterial cellulose material in a way that allows for the integration of electronic components. Methods were developed to allow for the embedding of conductive elements, sensors, and a variety of output components.

To assist designers, the team created a novel set of fabrication techniques that can be applied at three distinct phases of development, namely the growth, stabilization, and inanimate phases. The growth phase is crucial to the mechanical strength of the final product, as the organic material will grow around and encapsulate the electronics at this time. During the stabilization phase, the researchers have developed techniques to allow for the incorporation of conductive particles, which serve to connect components and create the final circuit layout. In the final inanimate phase, the growth of the biomaterial is complete, and subtractive techniques, like laser cutting and folding, can be used to shape the final device.

These methods were put to the test through the development of a number of HCI devices that demonstrate some of the possibilities that are being unlocked. In one case, a wearable device was created that sits on the shoulder. Measurements were captured from a galvanic-skin-response sensor and processed by an Arduino Leonardo development board. When the wearer is experiencing high levels of anxiety or stress, shape memory alloy actuators are triggered to lift flaps on the device, making the wearer’s emotional state known. In another demonstration, a video game controller was created, complete with a multi-touch matrix as a joypad and a number of capacitive buttons to trigger actions. The controller was connected to an Arduino Nano to allow it to interface with other devices.

While the team’s methods did allow for the successful integration of biomaterials and electronic components, some of the treatments that are required during fabrication impact the stability of the material. It was noted that in some cases, the bacterial cellulose can begin to degrade in as little as a few days. Some damage to the materials was also noted around the conductive traces and shape memory alloy actuators, as the heat they generated was sufficient to degrade the cellulose.

Despite these limitations, the interesting properties of Biohybrid Devices make them worthy of further research. Perhaps those kinks will get worked out in the future.