Proposed Implementation

Potential beyond Bricks

Pichitecture is a sustainable alternative material, providing an option for integrating carbon reduction and carbon fixation into building and construction. While our project focused on bricks, this isn’t where the story ends. In our opinion, considering our progress, expertise of our PIs and advisors as well as opinions of representatives of industry players, we believe there are various potential implementations for our project:

Supplementation in established production

In our work, we naturally dreamt big: the idea of seeing buildings and entire cities built with our material would be a dream come true. However, that isn’t the primary, or most practical, implementation of our project; at least, it isn’t something that is feasible in the near future. What would be the most readily available impact of our material would be in supplementation of existing materials and adaptation of existing buildings. The properties of the produced mixture highly depend on the proportions of the individual components [1], thus our material can be used for preservation of existing structures, making repairs and reconstruction more sustainable and an even more environmentally friendly solution.

Creation of difficult and custom structures

During conversations with industry representatives, our attention was drawn to another important potential use for our material, in this case one that makes use of one of our possible limitations. As the drying process circumvents the need for high temperatures, thus lowering the environmental damage, it could potentially take longer than conventional bricks to create the same amount, which would hinder existing supply chains. However, as mentioned before, our material finds use beyond bricks – a potential implementation of our material could be in larger, flat structures, such as walls and slabs. These structures could rather easily be poured and left to dry, allowing the creation of custom structures, adaptable to any construction need, which, currently, still may be troublesome to make with established procedures.

Self-healing and adjustment to specific properties.

Another aspect drawing increasing interest when it comes to Living Building Materials is self-healing. Self-healing materials are defined as smart materials that possess the ability to fully or partially recover a functionality that is mediated by operational use [2]. Recent research suggests that materials with cyanobacteria may possess some self-healing capabilities depending on humidity and processing [3]. Thus, another field of use for our material would be in application where self-healing is needed or preferred to large/small-scale repairs.

Bioethical and biosafety considerations

As stated in our human practices analyses, the general public tends to assessing their knowledge on synthetic biology as rather low. And, if asked what they associate with synthetic biology in their daily life, they name frequently mentioned roles of GMOs in the media: Food and Medicine. The use of GMOs in architecture is not widely known. However, according to Pew Research, a survey of 20 publics across Europe, Russia, the Americas and the Asia-Pacific region (2019-2020) showed that a median of 48% of respondents believe GMO foods to be unsafe, a big difference to the 13% who believe them to be safe [4]. While our project doesn’t produce consumable goods to be ingested, we do believe we need to consider this wide skepticism in our biosafety considerations.

Production, but not incorporation

In a wide implementation of our material, the incorporation of GMOs in the material may become an option; this is why we incorporated cyanobacteria in some of our brick mixtures. However, the safest version of our material would be one which incorporates products of GMOs, but not the GMOs themselves. Produced biopolymers (spider silk, gelatin, etc.) could be separated from Pichia pastoris / Synechocystis PCC 6803 culture via size exclusion chromatography or HIS-tagging, depending on what is easier to implement at an industry scale. Of course, in this version, self-healing or other properties necessitating the presence of microorganisms in the material would not be an option.

Incorporation, but no unsafe release

If incorporation is, on a large scale, the easiest option, as the separation step may be too expensive (temporally or monetarily), then, of course, our material needs strategies to curb unsafe release. Thankfully, synthetic biology has a variety of methods of ensuring biosafety. In our case, we believe the introduction of auxotrophies would provide negative selection pressure in the case of release of the microorganism. The introduced plasmids are an artificial metabolic burden on these organisms, making them less proliferative than wild type organisms or other yeasts/cyanobacteria.

A safety measure at a higher level would, of course, be the introduction of a kill-switch. This kill-switch could be adjusted depending on where the material is planned to be used: light exposure, atmospheric oxygen levels, or decreased temperature can all be potential triggers that could ensure biosafety of the material.

References

[1] Qiu, J., Artier, J., Cook, S., et al. (2021). Engineering living building materials for enhances bacterial viability and mechanical properties. iScience. Vol. 24., Issue 2.
[2] Bekas, D.G., Tsirka, K., Baltzis, D., Paipetis, A.S. (2016). Self-healing materials: A review of advances in materials, evaluation, characterization and monitoring techniques. Composites Part B: Engineering. Vol.87, 92-119
[3] Heveran, C., Williams, S. L., Qiu, J., et al. (2020). Biomineralization and Successive Regeneration of Engineered Living Building Materials. Matter. 2, 481-494.
[4] GMO Skepticism: https://www.pewresearch.org/fact-tank/2020/11/11/many-publics-around-world-doubt-safety-of-genetically-modified-foods/