iGEM Athens

IMPLEMENTATION

Our philosophy

The problem of synthetic colour is widely spread. Seeking nature’s own solutions and mimicking the colouring techniques observed in living organisms, could maybe provide an alternative to this worldwide problem. Inspired by that, the first step we followed was to observe the vivid colours found in many bacterial strains. We finally chose bacteria from the Flavobacterium genus that create an impressive iridescent colour as a result of their spatial arrengment observed in the micron scale. The next step was to think about how to turn this phenomenon into a useful application for the real world. We decided to engineer these bacteria using tools provided by synthetic biology, so that they excrete cellulose that retains the structural colouration. The final cellulose-based biomaterial could be used as a coating to be applied in a variety of surfaces. Cellulose-based optical structures are advantageous in terms of biodegradability [1]. Provided that mass-scale production is achieved, the proposed biomaterial can be implemented into different commercially available products, providing significant benefits to the well-being of multiple societal groups.

Applications

Structural colouration as a technique is still in its infancy and has yet to be widely implemented in each one of its potential applications. At the beginning of our brainstorming process, we envisioned our project to be used as an alternative to conventional dyes and our original vision was to implement it into textiles and building surfaces. That is because the desired properties of the biomaterial will be most suitable for these applications. However, there are many more ways to apply structural colouration into multiple fields, as presented below. The second and third categories that follow are the most relevant to what we opt for in this phase of our project.

Sensors

In general, materials that are structurally coloured can be used as chemical and biological sensors but also as versatile detectors. Some examples worth noting are [2-3]:

-detection of changes in potential concentrations of proteins and other biomolecules.

-optical index of ambient humidity in buildings.

-food packaging coating and damage from humidity or thermal exposure indicator.

-enforcement of the counterfeit prevention of bank notes

Coatings

Structurally coloured materials can be used to coat different surfaces in order to replace the synthetic dyes. Examples follow [4-6]:

-textile materials

-glass coatings

-aesthetic building skins

-flexible displays

-automotive paints

-bright displays for electronic compartments

Miscellaneous

Lastly, structural colour can be used in different ways such as [6]:

-cosmetics

-bioart

-painting

Societal groups

This proposed method has the potential of being integrated into two complementary sections of the production chain: the manufacturing and the consumption. Having a low environmental impact in every step of its life cycle, our biomaterial can introduce sustainable practices to the target groups that represent those two sections. Through our project design, we attempt to encourage the implementation of this product in parallel with the incorporation of the sustainability mindset and we address this plan to the following stakeholders.

Researchers

The project provides a novel technique that is easy to use, can be automated and provide researchers with a new way of producing structurally coloured organic materials. This will help to extend the very promising field of structural colouration with the potential to be further optimised before it enters the industry. Additionally, the growth of genetically engineered Flavobacteria can be achieved using few raw materials, and even industrial waste residues opening a new era towards production of more sustainable materials.

Material Manufacturers

We envision an affordable biomaterial, able to overcome the trade-off between cost and quality so it can be easily integrated in different industries, while being compatible with a variety of surfaces and not requiring labour-intensive processes for its scaling-up. Additionally, the need for fewer resources will ensure low carbon footprint in all stages of its production chain. This will provide companies with the ability to point out their corporate environmental responsibility.

Consumers

Using this colouring alternative in many daily-use products, consumers will have the opportunity to adapt into a safer, eco-friendly lifestyle.

Bioartists

Bringing innovative and safer colouring tools in the BioArt community will be an extra achievement.

Biosafety & Biosecurity concerns

Both safety and ethical issues need to be considered before the end-product is distributed to its end-users. When used as a colour substitute on textiles, packaging, cosmetics and elsewhere, our synthetic material will inevitably be in close proximity to human skin and mucosa, as well as gastrointestinal tract and respiratory system. Having this in mind, we carefully chose the main component of our biomaterial, cellulose. According to literature, cellulose is a well-studied, non-toxic and non-allergenic polysaccharide with plenty of existing commercial uses [1]. Therefore, no safety concerns are anticipated from human exposure to cellulose in general. In case any material additives are needed for the stabilization of the final product, they will be carefully selected and assessed for their biological interactions. Βacterial cells themselves would not be considered a threat to human health, as they will be carefully controlled until their final positioning on the biofilm surface and then will be eliminated, leaving the material cell-free. Even if unviable bacterial cells remain in the final product there are no concerns regarding safety because there is no evidence of pathogenicity and allergiogenicity by any of the genes in the strains we utilise (biosafety level 1).

The bacterial modification will only make the production of genetically engineered cellulose microfibrils possible. Therefore, no undesirable biosecurity outcomes are expected from our intervention to the system. However, a noticeable fact is that certain forms of structural colour can have antireflective properties. This can be reasonably perceived as an attractive opportunity for camouflage applications. In our case, though, Flavobacteria biofilms do not possess such properties and cases of misuse will be only investigated in the future if our biological system is further modified towards this direction.

Last but not least, since our structural coloured biofilm is meant to replace conventional colouring techniques, the general public needs to understand the product, how it is produced and how safe it really is. Bacterial involvement may sound obscure to someone. That's why public information and consent before use is equally as important as fair product design.

Challenges

Replacing colour with a product made by bacteria is not an easy task. Research on structural colour and its underlying mechanisms is relatively underdeveloped and thus adequate communication with experts in this field needs to be done before we can design the exact methodology for the isolation of the cellulose, while making sure it maintains its structure in the long term. The durability and mechanical properties of our end-product is therefore a parameter to be further investigated. Also, solid cultures are not common in large-scale production of bacterial cellulose and as a result the transition from solid to liquid cultures in order to adhere to the already used bioreactors and equipment in industries, should be investigated. The other option is to find an economic way for scaling up the solid cultures, which is something we have not yet examined. Finally, structural colour in general is a difficult concept for many people to understand and the abundance of everyday habits that include colour might make the transition to this alternative difficult. This incomprehensible physical phenomenon has to be explained in a simple way to the general public and stakeholders to ensure their understanding of this practice and maximise its potential of future implementation.

Team:Athens/Implementation