Kombucha SCOBY Bandages for Wound Dressing Tests

ISEF Category: Microbiology

Subcategory: Applied Microbiology  ·  Difficulty: Advanced  ·  Setup: School Lab  ·  Time: Full Year

The Hook

A bacteria-grown sheet can act like a tiny skin patch. That sounds odd, but a SCOBY already forms a flexible film on kombucha. If you can tune how it grows, you may change how well it blocks microbes, holds moisture, and resists tearing. That makes it a real materials project, not just a kitchen experiment.

What Is It?

A SCOBY is the living film that grows on kombucha. The name stands for symbiotic culture of bacteria and yeast. The microbes build a cellulose mat, which is a web of sugar chains that can dry into a thin sheet. Think of it like a natural fabric made by microbes instead of a loom.

For this project, you would treat that sheet like a possible wound dressing substrate. You would ask whether growth conditions change the film’s properties. pH and temperature can affect how the microbes build the cellulose network, so the film may end up stronger, weaker, drier, or better at holding antimicrobial compounds. You are not testing a medical product for use on people. You are testing a material idea that could someday inform biomaterials research.

Why This Is a Good Topic

This topic works well because you can measure several traits from one material, and each trait gives you real data. Strength, moisture-vapor transmission, and antimicrobial retention are all testable with careful setup. The project connects to wound care, biomaterials, and safe, low-cost material design. You can also make it competitive by comparing growth conditions, running repeated trials, and using clear statistics.

Research Questions

• How does growth pH affect the tensile strength of dried SCOBY films?
• What is the effect of incubation temperature on moisture-vapor transmission through SCOBY films?
• Does changing growth pH alter how much antimicrobial activity remains in the finished film?
• To what extent do SCOBY films grown at different temperatures resist tearing under a simple load test?
• Which growth condition produces the best balance of strength and breathability for a dressing-like film?
• How does post-growth washing or drying change antimicrobial retention in SCOBY films?
• Does film thickness explain more variation in strength than growth pH does?

Basic Materials

• Food-grade kombucha starter liquid with active SCOBY cultures.
• Clean glass jars with breathable covers.
• Distilled water.
• pH test strips or a basic pH meter.
• Thermometer.
• Small digital kitchen scale with 0.1 g accuracy.
• Ruler or measuring tape.
• Binder clips or simple clamps.
• String or fishing line for hanging load tests.
• Identical paper clips or washers as test weights.
• Stopwatch.
• Nonwoven gauze or sterile gauze pads for comparison.
• Gloves and safety glasses.
• Notebook for data tables.
• Camera or phone for documenting film appearance.

Advanced Materials

• Autoclave-safe glassware or access to sterile technique supplies.
• Incubator or temperature-controlled chamber.
• pH meter with calibration buffers.
• Analytical balance.
• Texture analyzer or materials testing frame.
• Water vapor transmission testing setup or desiccant cup method supplies.
• UV-vis spectrophotometer for antimicrobial diffusion assays.
• Petri dishes and agar media.
• Sterile forceps and pipettes.
• Digital micrometer for thickness measurements.
• ImageJ-ready calibration target for area and defect analysis.
• Standard bacterial strain approved by your school lab.
• Lab notebook and sample labeling system.

Software & Tools

• Google Sheets: Organizes your trial data, calculates averages, and builds graphs for comparisons.
• ImageJ: Measures film area, thickness references, and visible defect patterns from photos.
• R: Runs statistical tests and helps you compare multiple growth conditions cleanly.
• Python: Automates data cleanup and plots trends across pH, temperature, and film strength.
• PubMed: Helps you find review articles and research papers on bacterial cellulose and wound dressings.

Experiment Steps

1. Define the exact property balance you want to optimize, such as strength, breathability, and antimicrobial retention.
2. Choose one growth factor to vary first, then lock the rest so your results stay interpretable.
3. Plan how you will standardize film size, drying method, and thickness before testing.
4. Build separate test plans for mechanical strength, moisture movement, and antimicrobial comparison.
5. Set up controls that let you compare SCOBY films against a known material and a no-treatment baseline.
6. Decide how you will summarize performance with a scoring system or trade-off chart.

Common Pitfalls

• Letting film thickness vary too much between samples, which hides the effect of pH or temperature.
• Testing strength on wet and dry films in the same way, which makes the measurements mean different things.
• Comparing samples with different drying histories, which changes flexibility and tear resistance.
• Using inconsistent light, distance, or background in photos, which makes defect and thickness analysis unreliable.
• Treating antimicrobial zones as proof of medical safety, which they are not without proper lab validation.

What Makes This Competitive

A strong project will do more than say one sample looks better. You can compare several growth conditions, measure multiple properties, and look for trade-offs between them. The best version will use careful controls, repeated trials, and statistics that separate real effects from noise. You can also stand out by building a performance index that combines strength, breathability, and antimicrobial retention into one clear ranking.

Project Variations

• Test SCOBY films grown from different tea substrates and compare whether the feedstock changes strength and moisture control.
• Compare raw SCOBY films with films infused after growth with a safe model dye or plant-derived antimicrobial compound to study retention.
• Measure how drying method changes film porosity, tear resistance, and water-vapor movement in the same batch of SCOBY material.

Learn More

• PubMed: Search for review articles on bacterial cellulose, wound dressings, and antimicrobial biomaterials.
• NIH PubMed Central: Find free full-text papers on microbial cellulose films and biomedical applications.
• Journal of Applied Microbiology: Search for studies on cellulose-producing bacteria and material properties.
• Carbohydrate Polymers: Look for papers on bacterial cellulose structure, strength, and water handling.
• MIT OpenCourseWare: Search for materials science and biomaterials lecture notes that explain testing methods.
• USDA National Agricultural Library: Search for background on fermentation, cellulose, and food-grade microbial cultures.