The overall goal of our project this year is the development of a silk mesh material, Caddisgraft, through synthetic biology for use as a B2B commercial product. We seek to address the usage of toxic, non absorbable plastics such as polypropylene and polyethylene terephthalate in cosmetic surgeries and hernia surgeries. Inspired by the work of previous iGEM teams, our design combines silkworm silk (a comparatively cheap and rigorously evaluated surgical material) and caddisfly silk (fully animal-free protein material). This mesh can easily be customized to individual patients with our fully 3-D printable glue gun.
The main values we were considering while developing the mesh material were largely based on improving the post operative outcomes in cosmetic surgeries. We would be reducing plastic medical waste both from fewer materials being used but also due to fewer recurring surgeries after the initial operation.
Caddisfly larvae produce silk underwater for protection. Despite the aquatic environment, their silk production process is similar to that of terrestrial arthropods. Silk production involves synthesizing fibroin in the posterior region of the silk glands and adhesive glycoproteins in the anterior region. These substances combine to form functional silk, with proteins transported from the ER to the Golgi apparatus, merging into secretory granules, and released through merocrine secretion.
Aquatic caddisflies, unlike their terrestrial relatives, use silk for constructing protective shelters in flowing water. Their silk, described as flat ribbons or fine meshes, is particularly effective as a medical bioadhesive, adhering to both organic and inorganic surfaces underwater. This silk is composed mainly of large fibroin proteins, enabling its performance in aquatic settings.
The caddisworm builds its silken case from a lengthy fiber, creating a mesh of cases with a denser outer layer coated with adhesive. Silk secretions are emitted through a spinneret and solidify upon contact with water, forming a twin-stranded material.
Caddisfly silk, composed of two filaments from labial glands, primarily features h-fibroin, lacking the glycoprotein P25 found in silkworm silk. The structure of Trichoptera h-fibroin resembles that of Lepidoptera, with repetitive (SX)nE motifs and glycine-rich regions. Recent studies increased the number of full-length Trichoptera h-fibroin sequences from four to eleven, revealing similarities in gene organization and amino acid composition across different caddisfly clades. Notable differences include a lower alanine content in Trichoptera h-fibroin compared to Lepidoptera, influenced by distinct protein folding mechanisms.
Caddisfly silk has been assessed for sterilizability, finding it maintain its properties after UV sterilization and other treatments. Temperature stability tests showed that silk remains stable up to 150°C, with degradation beginning at higher temperatures. Tyndallization and autoclaving proved most effective for sterilization, with UV irradiation and ethanol reducing but not eliminating bacterial colonies.
At the early stages of our project this year, we met with Rickey Egan, a researcher at the Applied Physics Lab at Johns Hopkins, who we actually met at the iGEM Jamboree in 2023. He was willing to provide some mentorship at the time, and connect us with resources. We had multiple discussions about the project direction, and also how we could further our progress on our project since the previous year.
Shortly after submitting our proposal to the Johns Hopkins Healthcare Design Competition, we decided to enter HopStart, a competition for student ventures at Hopkins. We were assigned a mentor, Josep, who is a data scientist at Nasdaq, and in our weekly meetings, he truly provided a fresh perspective. We learned many hard lessons thorugh the process since it was our first time learning how to pitch a product for a specific business use case, including BEP and CAC costs. We are so grateful to him for providing the initial early feedback that allowed us to refine our strategy over time.
In March, we were still trying to raise money for funding our project, since we wanted to avoid the obstacles of last year's project. We reached out to Josh Ambrose, who is director of the Pava Center for Entrepreneurship at Johns Hopkins. We asked him critical questions, including whether or not we should pursue a licensing vs. startup approach for our product. At the end, he also provided us with resources of more grants we could apply to, which helped us immensely in not only gaining more funding, but also growing our network.
In April 2024, we met with Dr. Paul Frandsen, a caddisfly silk researcher at Brigham Young University and a valuable resource towards the Caddisilk project in the previous iGEM cycle. We discussed our new plans regarding protein synthesis strategies and drylab modeling options based on genetic sequences from Frandsen’s lab. He provided helpful advice based on his lab’s research, and shared findings on specific regions in the sequence that could be modeled. Dr Frandsen also put us in contact with Danyon Gedris, a senior in his lab at the time, who we have worked closely with on wetlab strategies and protocols. Dr Frandsen and Danyon provided invaluable technical advice for both our drylab and wetlab subteams, and Danyon is now an official advisor of our team, having started pursuing his PhD at Hopkins!
Shortly after the HopStart competition in April, we reached out to Sarah Mogol who was a judge for our track, and asked for her advice on commercialization and legal advice. A big lesson we learned was how we would deliniate from being a student organization at Hopkins with the work of a startup. We had a very honest conversation with Sarah and truly valued her advice in terms of how to protect ourselves with regards to intellectual property.
In July, we reached out to Dr Michael Kessler from the Department of Materials Science and Engineering at Johns Hopkins. We presented our SilkSnare caddisfly fishing net idea, and he was intrigued by the properties of caddisfly silk and the implications of synthetically producing it, but also advised us against targeting the fishing industry due to feasibility issues with production scale and cost. He encouraged us to investigate the use of caddisfly silk as a biomaterial, and the department generously sponsored $500 towards the iGEM Team at Johns Hopkins.
In August of 2024, we met with Samuel Ball-Brau, a healthcare consultant, to ask for his advice in applying our product to the medical field. He pointed us towards bariatric surgery, suggesting that this emerging field would benefit from a safe, biodegradable adhesive, and challenged us to find a way to make bariatric surgery safer and more effective. Our research into bariatric surgery solidified our project direction, and in September we presented CaddisGraft, a biodegradable hernia mesh for surgical use. Mr Ball-Brau was impressed with our concept and gave us pointers on our presentation visuals and illustrative plan, and we are working with him to establish connections in the field and raise funds to support our research.
We held monthly meetings with Dr. Winston Timp, a professor in the Department of Biomedical Engineering at Johns Hopkins and our advisor. He provided valuable wetlab advice, access to a lab space, and guidance on meeting project milestones and deliverables.
We integrated feedback from various events and stakeholders to further the design of our product! Here are some of the people we spoke to:
During our weekly Monday meetings, Josep brought up many weaknesses in our initial business plan strategy, but also helped to quell any fears we had about creating a startup. Our discussions prompted us to think about the customer we were planning to sell to, which dictated what kind of application we would have. We wanted to see if we could continue in the direction of silk fishing nets, but he advised that we would need to strategically price them to turn a profit eventually. There were tradeoffs discussed between going into a more medical application, which would have high R&D and trial costs, vs. something more commercial, which sells at a lower price but may have a lower barrier to entry. We also had a candid discussion about where we saw ourselves as entrepreneurs, and what being on the iGEM team meant for the development of the startup.
After HopStart, Sarah provided much guidance about what we were plannign to do as a team afterwards, and was a champion of our biodegradable silk fishing net solution, SilkSnare. She was very frank about the importance of protecting ourselves early on with NDAs because of her past experiences, and having a lawyer of some kind to facilitate our connections with others. However, after this meeting, as a team, we did some self reflection, and were still somewhat unsure about the long-term feasibility of doing fishing nets. We knew that this material could have other applications, so we kept our minds open to new perspectives as we refined our solution.
In August of 2024, we met with Samuel Ball-Brau, a healthcare consultant, to ask for his advice in applying our product to the medical field. He pointed us towards bariatric surgery, suggesting that this emerging field would benefit from a safe, biodegradable adhesive, and challenged us to find a way to make bariatric surgery safer and more effective. Our research into bariatric surgery solidified our project direction, and in September we presented CaddisGraft, a biodegradable hernia mesh for surgical use. Mr Ball-Brau was impressed with our concept and gave us pointers on our presentation visuals and illustrative plan, and we are working with him to establish connections in the field and raise funds to support our research.