Constraints
Biodegradable and Biocompatible: The hybrid material must not cause any immune response, cytotoxicity, or allergic reactions in human tissue.
Sterility: Contamination must be highly regulated and prevented to ensure a sterile end product is reached. All impurities must be fully characterized and confirmed sterile.
Stability: The material must remain sterile and structurally viable while in long-term clinical storage environments.
Scalability of Production: The kombucha fermentation processes and curli fiber engineering and production must be reproducible at industrial scales, not just in lab batches
Standardization: The product must conform to all existing biomedical testing standards for wound dressing.
Waste Management: Disposal of waste containing genetically engineered biomaterials must strictly follow all biosafety regulations.
Sourcing and Cost: Long term viability relies on designing a cost-effective method of production and consideration of reliable sources for cellulose feedstock and microbe cultures.
Criteria
Antimicrobial Properties: The antimicrobial peptides on the patch must demonstrate sustained efficacy (>48 hours) against Candida tropicalis, a yeast species frequently implicated in nosocomial wound infections. The antimicrobial activity should include both rapid initial killing and prevention of recolonization for the duration of patch application. Antimicrobial effectiveness must be validated under physiologically relevant conditions (temperature, pH, serum exposure). A 99.9% reduction of Candida tropicalis colony-forming units (CFU) within 2 hours of application, under simulated wound fluid conditions.
Rehydration Capabilities: For storage and distribution, the wound patch must be storable in a dehydrated state for a minimum of 6–12 months without loss of antimicrobial efficacy or structural integrity. Upon rehydration, the patch must fully recover functional performance (antimicrobial activity, flexibility, porosity) within a clinically practical timeframe (≤5 minutes). Dehydration/rehydration cycles must not significantly degrade cellulose matrix or nanofiber functionality.
Mechanical Integrity: The patch must maintain tensile strength and flexibility under handling and application conditions. Structural integrity should be preserved throughout rehydration and wear, with no fiber shedding into the wound. Must have an ultimate tensile strength (hydrated patch) of ≥ 1.0 MPa (sufficient to withstand handling and repositioning). The elongation at breaking must be ≥ 10%, ensuring flexibility during application and patient movement. In addition, the patch must tolerate ≥ 100 bending cycles around a 5 mm radius mandrel without visible cracking or delamination.
Ease of Use: Application, removal, and maintenance of the wound patch must be straightforward and require no specialized training. The hydration/rehydration step should be simple, reproducible, and feasible under hospital and field conditions (sterile saline or distilled water). Packaging should ensure sterility and allow for rapid deployment in clinical settings. The application process should be no more than 5 steps and should have a first time user success rate of 95%.
Comfort: The patch must maintain a porous architecture to support oxygen diffusion and prevent moisture accumulation at the wound interface. Thickness should be maintained between 0.5–1.0 mm, with sufficient flexibility to conform to dynamic skin movements without detachment. Adhesive properties should provide secure attachment without causing skin irritation or damage upon removal for 48-72 hours.
Standards
NIH Guidelines for Research Involving Recombinant DNA Molecules:
A set of standards used to manage biological risks when working with recombinant DNA molecules and microbes. This set of standards has multiple sections, including how to work with microbes safely, utilize recombinant DNA, and maintain safe laboratory practices.
FDA Code of Federal Regulations Title 21:
The FDA Code of Federal Regulations Title 21 regulates food, drugs, biologics, cosmetics, and medical devices.
§ 878 - Specifically for our project, FDA Title 21 covers standards for all medical dressings.
ISO 13485:
ISO 13485 is a set of standards that is internationally implemented by the International Organization for Standardization to maintain the quality of medical devices, including our wound dressing, during the manufacturing and distribution process. The set of standards covers medical devices' design, development, production, installation, and servicing.
ISO 10993-1:
The ISO 10993-1 set of standards establishes the requirements that must be met to assess the biological safety of medical devices/technologies. This set of standards is upheld by the International Organization for Standardization and is highly applicable to wound care technology. ISO 10993-1 provides specifications for limiting the biological risks that are posed by technology that is in contact with human tissues. ISO-10993-1 also outlines the biological risks correlated with medical device material selection.
Citations:
Health, C. for D. and R. (2023). Code of Federal Regulations (CFR). FDA. Retrieved from https://www.fda.gov/medical-devices/overview-device-regulation/code-federal-regulations-cfr
ISO - ISO 13485 — Medical devices. (2019, December 18). Retrieved December 12, 2025, from https://www.iso.org/iso-13485-medical-devices.html
ISO 10993-1. (2025). Retrieved December 12, 2025, from https://www.iso.org/standard/10993-1
NIH Guidelines for Research Involving Recombinant or Synthetic Nucleic Acid Molecules (NIH Guidelines). (2008).