Bacterial cellulose (BC) has been explored for use in a range of applications including tissue engineering and textiles. BC can be produced from waste streams, but sustainable approaches are needed for functionalisation. To this end, BslA, a B. subtilis biofilm protein was produced recombinantly with and without a cellulose binding module (CBM) and the cell free extract was used to treat BC either ex-situ, through drip coating or in-situ, by incorporating during fermentation. The results showed that ex-situ modified BC increased the hydrophobicity and water contact angle reached 120°. In-situ experiments led to a BC film morphological change and mechanical testing demonstrated that addition of BslA with CBM resulted in a stronger, more elastic material. This study presents a nature inspired approach to functionalise BC using a biofilm hydrophobin, and we demonstrate that recombinant proteins could be effective and sustainable molecules for functionalisation of BC materials.

Bacterial cellulose (BC) has gained significant interest for various applications due to its useful properties which include chemical stability and strong physical properties as well as its biocompatibility. However, conventional fabrication methods are limited by a lack of control over the form, particularly depth and thickness, restricting BC applications to 2D planar shapes. The production of BC is constrained by the formation of a pellicle at the liquid–air interface. To overcome this constraint and enable continuous pellicle formation, a method was established to combine intermittent batch feeding with a supportive mesh scaffold. Intermittent feeding supplies nutrients to the pellicle, promoting sustained formation at the liquid–air interface, while the supporting mesh anchors the initial pellicle to prevent submersion. This approach facilitates the continuous growth of BC pellicle at a controlled rate. Moreover, the method described here results in a single BC pellicle with enhanced thickness, weight (both wet and dry states), water-holding capacity and mechanical strength. Continuous growth is achievable with ongoing nutrient supply, allowing for precise control over the final pellicle thickness. This culturing method is scalable and has been tested for volumes ranging from 250 mL to 10 L, and significantly increases glucose-to-cellulose conversion (3.4-fold) and water utilization efficiency (2.4-fold).

Designing with biological materials as a burgeoning approach in the architecture field requires the development of new design strategies and fabrication methods. In this paper, we question if designers can use a parametric design approach while working with living materials. The research uses fungi as a biomaterial probe to experiment with the parametric behavior of living systems. Running design experiments using fungi helps to understand the extent to which biological systems can be considered parametric and, if so, what kind of parametric systems they are. Answering these questions provides a method to work with complex biological systems and may lead to new approaches of fabricating materials by tuning the environmental parameters of biological growth.

In this paper, we describe the first steps in the design of a synthetic biological system based on the use of genetically modified bacteria to detect elevated pressures in soils and respond by cementing soil particles. Such a system might, for example, enable a self- constructed foundation to form in response to load using engineered bacteria which could be seeded and grown in the soils. This process would reduce the need for large-scale excavations and may be the basis for a new generation of self-assembling and responsive bio-based materials. A prototype computational model is presented which integrates experimental data from a pressure sensitive gene within Escherichia coli bacteria with geotechnical models of soil loading and pore water pressure. The results from the integrated model are visualised by mapping expected gene expression values onto the soil volume. We also use our experimental data to design a two component system where one type of bacteria acts as a sensor and signals to another material synthesis bacteria. The simulation demonstrates the potential of computational models which integrate multiple scales from macro stresses in soils to the expression of individual genes to inform new types of design process. The work also illustrates the combination of in silico (silicon based computing) computation with in vivo (in the living) computation.

Biological materials have been used in construction for as long as we have used wood and limestone; however, biotechnologies seem to offer the potential to grow materials to our specifications and even to allow complex structures to be self-assembled through biological processes. Several promising materials have been identified, including microbially induced calcium carbonate as a cement or mycelium grown on waste materials, which has potential as a structural or insulation material. These developments run parallel to a speculative design discourse – in which features future cities are grown, kept living and self-adapt – as well as research into engineered living materials (ELMs), at the cutting edge of material science and synthetic biology research into ELMs. This question invites a wide range of research contributions in which we identify, evaluate and speculate on the role that grown materials and structures will have on the future of construction. We invite not only experimental work on the latest method in this area but also critique and reflection beyond the ‘hype’ of these, potentially transformative, technologies and approaches.