Incorporating living cells into a non-living matrix is one of the many possible steps that can be undertaken to stop climate change. Especially, photosynthetic organisms have a promising future in material design as they can capture atmospheric carbon dioxide and ’ breathe’ oxygen. This research dives into unravelling the properties of a hydrogel-based living material containing C. reinhardtii.
To facilitate a systematic exploration, this goal was divided into three smaller pieces. Firstly, the study delves into the mechanical characteristics, aiming to identify the most suitable bio-ink crosslink technique and composition. To validate the mechanical properties the living material was subjected to rheology and a bridging test. Concluded can be that crosslinking and algae growth improve the mechanical stability of the material, whereas, gelatin did not. The sagging behaviour of the material looked promising.
Secondly, the photosynthetic activity of this living material was researched. It was found that the rise of O2 levels can not be measured accurately, the non-living matrix can release a high amount of CO2 of over 20.000 ppm and airtightness poses a complex challenge in this field of research.
Lastly, the project incorporates attempts to find effective techniques for studying the livingness of this unique material. In this part of the research, inverted optical microscopy, 3D laser scanning microscopy and chlorophyll extraction were discarded as suitable methods to study the livingness of the algae material. It was proven that leveraging the autofluorescence of the algal chlorophyll confocal laser scanning microscopy gives high-resolution images and the livingness of this living material could be studied with this technique in the near future.
This research significantly contributes to our understanding of this hydrogel-based living material and its many challenging properties. It underscores the importance of innovative materials like these in addressing contemporary environmental challenges, particularly in carbon capture. Moreover, it highlights the complexity of characterizing such materials, paving the way for further exploration and development in this relatively new field.

This project started with analyzing the different roles and potentials that bacteria have for the growth of new materials with ecological benefits. Here questions arise about the role that a designer can fulfill in the development of such novel materials. What new skillset does he/she need to obtain? How will a collaboration with biologists take place? In order to get a better understanding of the potentials of materials grown by bacteria and the subsequent role of a designer, a Material Driven Design (Karana et al., 2015) project was performed in collaboration with scientists from the Aubin-Tam research group, part of the Bionanoscience department of the Delft University of Technology. The starting point of the design project was a composite material consisting of three ingredients that are grown by three separate species of bacteria. In order to gain an understanding of how this material was grown and produced, the designer performed a plethora of experiments investigating; the growth of the organisms and the amount of material they produced; how the ratio between the three ingredients influenced the resulting material; how the way in which the material was processed resulted in its final form and properties. This led to the understanding that this material is highly programmable in its form and properties such as its flexibility, strength and surface roughness. With this in mind, user studies were performed in which it was found that the versatility of the material was considered interesting and intriguing by participants. They wonder what it is and how it is made, finding it hard to believe that bacteria grew such a material. This led to a material concept in which the designer proposes to play with these varying properties of the material, resulting in contrasting material experiences and highlighting the material its ability to appear as something that is both natural and man-made at the same time. This was done by exploring various processesing potentials of the material and analysing how different parameters of these processes influence the resulting material its properties. In doing so, the designer provided a framework by which future designers can program and explore this bio-based material that shows a lot of different potentials.