7. BioFabricating Materials¶
Research¶
Biomaterials are materials developed to interact with biological systems, offering innovative solutions in sustainable design and advanced technologies. Within this category, the approaches of "growth-based biomaterials" and "blended biomaterials" represent two distinct methods in the production of sustainable materials.
Growth-based biomaterials are created using living organisms such as bacteria, fungi, or algae, which produce material structures as part of their lifecycle. Notable examples include mycelium cultivation for bioplastics and natural textiles like kombucha scoby (Symbiotic Culture of Bacteria and Yeast), used to produce bio-textiles. This approach leverages natural biological processes, enabling the development of customized, regenerative, and biodegradable materials.
On the other hand, blended biomaterials are crafted by combining natural ingredients, such as organic waste (e.g., fruit peels or vegetable scraps), with binding agents that preserve their biodegradability. These materials do not rely on living organisms during their production but stand out for their versatility and ability to repurpose waste, transforming it into useful products such as panels, packaging, or sustainable utensils.
Both approaches offer unique perspectives in the transition toward more environmentally responsible design and manufacturing, exploring the intersection of biology, design, and technological innovation.
References & Inspiration¶
Yuhan Bai is a designer recognized for her innovative approach to sustainable materials, particularly showcased in The Soil Project, developed during her studies at the Royal College of Art. Bai creates an alternative leather material using soil combined with natural ingredients such as gelatin, agar, starch, glycerin, and gluten. This material, molded and laser-cut, mimics the properties of traditional leather but offers greater flexibility, resembling silicone in texture.
Her collection features sculptural pieces, including a corset inspired by nature, photographed in settings that blend organic and cyberpunk aesthetics. Bai employs this material both as a primary component in new garments and as a medium for restoring and redesigning vintage pieces. Her work embodies a philosophy that merges natural processes with sustainable design, emphasizing the connection between fashion and the environment.
Bai's project aligns with the growing trend of biomaterials and responsible production methods in the fashion industry, demonstrating a forward-thinking approach to eco-conscious design.
Process and workflow¶
For my work process, I started by researching the materials I could recreate. With guidance from Anastasia and Nuria, we were advised to begin cultivating kombucha well in advance. This was crucial to allow the culture to develop a cellulose layer at least 1 cm thick, as it would thin out during the drying process.
kombucha "growth-based biomaterials"¶
From a biomaterials perspective, kombucha is a fermentation process that cultivates a bacterial cellulose matrix produced by a Symbiotic Culture of Bacteria and Yeast (SCOBY). This material is a byproduct of fermentation, where bacteria convert sugars into cellulose while yeasts ferment the sweetened tea.
The cellulose generated through this process has unique properties that make it suitable for biomaterial applications:
- Biodegradability: It is entirely natural and easily decomposes in the environment.
- Versatility: It can be dried and shaped into flexible or rigid forms, depending on design needs.
- Customization: The cultivation conditions, such as fermentation time or additives in the medium, allow for modifications to the final material properties.
- Sustainable production: Its production requires minimal resources and has a significantly lower environmental impact compared to synthetic materials like conventional leather.
In design and fashion, this biomaterial is used to create fabrics, accessories, and artistic experiments, as it can be dyed, printed, or combined with other elements for innovative finishes.
Ingredients & Recipes¶
* Tea: Preferably black or green tea, as it provides essential nutrients for the SCOBY.
* Sugar: Regular white sugar to feed the bacteria and yeast.
* Water: Filtered or boiled to avoid contaminants that could interfere with fermentation.
* Inoculum, Starter liquid: A portion of already fermented (unsweetened) kombucha to lower the pH and prevent contamination.
* Container: Preferably wide and shallow to allow the SCOBY to grow horizontally.
* Cloth or cheesecloth: To cover the container, ensuring ventilation while keeping out dust and insects.
* Rubber bands: To secure the cloth over the container.
* Non-metal utensils: Wooden, plastic, or silicone spoons or spatulas to handle the ingredients without altering the pH.
* Scale: To accurately measure sugar and tea quantities.
* Thermometer (optional): To ensure the tea solution is at room temperature before adding the SCOBY.
Prepare a sweetened tea solution, allow it to cool to room temperature, and then pour it into the container. Add the remaining ingredients, finishing with the starter liquid.
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Initial Chemistry: Dissolving sugar (sucrose) in hot water and mixing it with tea creates a medium rich in carbohydrates and bioactive compounds like polyphenols and tannins. These nutrients are essential for SCOBY growth.
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Fermentation: Initial Stage (0-3 Days) Yeasts: Yeasts begin fermenting the sugar, breaking it down into ethanol and carbon dioxide. Reaction: C₆H₁₂O₆ (glucose) → 2 C₂H₅OH (ethanol) + 2 CO₂ (carbon dioxide). This process generates bubbles and slightly increases the alcohol content. Bacteria: Meanwhile, bacteria convert ethanol into organic acids, such as acetic and gluconic acid. Reaction: C₂H₅OH + O₂ → CH₃COOH (acetic acid).
- Fermentation: SCOBY Development (3-14 Days) Cellulose Production: Bacteria from the Acetobacter genus synthesize bacterial cellulose on the liquid's surface. Chemistry: They use glucose to form long cellulose chains, creating the SCOBY matrix. Reaction: Glucose → β-D-Glucose → Polysaccharide (cellulose). pH: During this stage, the medium's pH gradually decreases, becoming more acidic (pH ~2.5-3.5). This protects the culture and gives kombucha its characteristic tangy flavor. Microbial Balance: A symbiotic balance between the yeast and bacteria is established, where both rely on each other for nutrients and removal of byproducts.
- Environmental Conditions Optimal Temperature: 20-30°C. Higher temperatures speed up fermentation but may reduce the quality of the SCOBY. Oxygen: Essential for SCOBY bacteria, as acetic acid and cellulose require oxygen for formation. Fermentation Time: A longer fermentation period results in a thicker cellulose layer. However, excessive fermentation can make the material too acidic.
- Thickness of the Biomaterial Key Factors: Container Surface Area: A wide container promotes greater cellulose formation. Nutrients in the Medium: A proper balance of sugar and tea optimizes cellulose synthesis. Time: At least 1-2 weeks are required to produce a layer approximately 1 cm thick.
Experimentation¶
For my experimentation, I divided the cellulose into three parts. One portion remained untreated to serve as a control for comparison. The second was coated with coconut oil to observe whether it would absorb any properties from the oil.
The third portion was blended and mixed with thermochromic pigment to analyze how it would behave and observe any resulting changes.
* Chlorine
* Water
* Coconut oil
* Thermochromic pigment
Upon drying, the samples shrank. The first two exhibited similar characteristics, with a slightly translucent appearance and a rough texture. In contrast, the blue sample (sample 3) became thinner and smoother; however, the thermochromic pigment successfully retained its functionality.
Bio-thread "blended biomaterials"¶
The bio-thread, made from sodium alginate, glycerin, and water, can be created using simple tools such as a syringe and a water-filled basin. This method blends principles of polymer chemistry and sustainable biotechnology, offering an accessible and adaptable process.
Ingredients & Recipes¶
* Glycerin
* Wate
* Sodium alginate
Detailed Process Using Specific Tools Preparation of the Mixture:
- Dissolve sodium alginate in water to create a homogeneous solution. Add glycerin as a plasticizer to enhance the flexibility of the material.
- Mix thoroughly to eliminate clumps and achieve a viscous yet fluid consistency.
Thread Extrusion:
- Fill a syringe with the prepared solution.
- Prepare a basin with water mixed with a calcium chloride solution. This gelation bath is crucial for forming the thread.
- Gently press the syringe to release the solution into the basin. Upon contact with the water and calcium ions, the alginate solution solidifies into threads through a process of ionic gelation.
Drying and Finishing:
- Carefully remove the formed thread using tweezers and rinse lightly if needed.
- Allow the thread to dry at room temperature or use controlled heat to speed up the process.
- The drying time will influence the final properties of the bio-thread, such as its strength and texture.
Advantages of This Method: - Manual Control: Using a syringe allows precise adjustment of the thread’s thickness based on the applied pressure. - Simplified Process: The water basin ensures uniform gelation in a controlled environment. - Customizability: By altering the ingredient proportions, threads with varying mechanical properties can be created.
Final Properties of the Bio-Thread:
Biodegradability: Naturally decomposes, making it environmentally friendly. Adjustable Flexibility: Dependent on the amount of glycerin and drying conditions. Versatility: Suitable for applications ranging from textiles to biomedical uses. This process presents an innovative and sustainable approach to creating materials, allowing for tailored design and properties to suit diverse project requirements.